1. 1. PART 1 Text 1 Geology (4500) 1. Learn the words and word combinations before reading: solid matter ['sOlId'mxtq] - encompass - [in'kAmpqs] - breakdown - ['breikdaun] - constituent - [kqn'stitjuqnt] - , to be in excess of aqueous - ['eikwiqs] - , vapour - ['veipq] - , tripoli ['trIpqlI] suffuse [sq'fjHz] , gemstone , nitrogen - ['naitrqdZqn] - exogenous processes - , trough - [trOf] - , diverse transformations -[dai'vWs] - 2. Mind the the prononciation of the following words: Geology - [dZi'OlqdZi]; Geologist - [dZi'OlqdZist]; Geological -[dZiq'lOdZikql]; Earth - [WT]; biosphere ['baIq"sfIq] ; lithosphere ['lITq"sfIq]; hydrosphere ['haIdrq"sfIq]; atmosphere ['xtmqs"fIq]. 3. Read and translate the text: Geology (from Greek: geo, "earth"; and , logos, "speech" lit. to talk about the earth) is the science and study of the solid matter that constitutes the Earth. Encompassing such things as rocks, soil, and gemstones, geology studies the composition, structure, physical properties, history, and the processes that shape Earth's components. It is one of the Earth sciences. The age of the Earth, determined on the basis of the known rate of breakdown of radioactive elements entering the crust, is calculated to be in excess of 4,000 Ma* . Geologists help to locate and manage the Earth's natural resources, such as petroleum and coal, as well as metals such as iron, copper, and uranium. Additional economic interests include gemstones
2. 2. and many minerals such as asbestos, perlite, mica, phosphates, zeolites, clay, pumice, quartz, and silica, as well as elements such as sulfur, chlorine, and helium. The atmosphere (from the Greek atmo- air and sphaere - sphere) is the layer of the air which envelops the earth. Essentially it consists of nitrogen and oxygen with a small quantity of water vapours, carbon dioxide and certain rare noble gases, notably argon. The hydrosphere (Greek hydro-water) is the aqueous shell which includes all the natural waters the waters of oceans, seas, lakes, rivers, which cover more than 70 of the earths surface, and also the underground waters, suffusing the rocks of the earth. The lithosphere (Greek lithos- stone) is the outer solid shell of the earth. Thats the very thing interesting for geologists. The lithosphere comprises several shells. The outer cover (shell) of the Earth, known as the Earth's crust, is the shell on which we live and the one accessible for our investigation. We obtain most of information concerning the Earth from our studies of the composition and structure of the Earth's crust. Throughout this vast span of time the Earth's crust has been undergoing continual changes. Forces within the Earth, the so-called endogenous (internal) forces, have caused parts of the crust to be uplifted or lowered as well as folded and buckled into high mountains and deep troughs. Always, the exogenous (external) forces of the Earth such as the wind, water, and extreme variances of temperature have been at work wearing away all land areas above the sea. While high mountains in one region were being worn away to flat plains, the lowlands in other areas were being elevated into highlands. Thus, portions of the Earth's crust have repeatedly been raised to great heights and then worn away. The lithosphere is composed of rocks, such as granite, basalt, sandstone, limestone. Rocks are complex natural bodies, composed of chemically and physically simpler bodies called minerals. Examples of minerals are quartz, feldspar and mica which form granite or calcite which is a basic constituent of such rocks as limestone and marble. Minerals in turn are a combination of separate chemical elements. Minerals are natural bodies, individualized physically or chemically, arising in the earths crust as a result of physico- chemical processes, without any particular interference into these processes by man. The biosphere (Greek bios- life) is the envelope of the earth which is the site of organic life. This sphere of life as it were* , the atmosphere, the hydrosphere, and upper part of lithosphere is a material factor in the diverse transformations and changes occurring in the parts of the earth near the surface. Living organisms destroy and alter rocks and minerals that had formed earlier, which gives rise to* new compounds and new minerals; furthermore, they themselves furnish* the material for the accumulation of organic rocks, such as limestones, tripoli, chalk, coal, etc. Notes: * Ma mega anna (lat.) 106 years, i.e. one million years 2
3. 3. * as it were * to give rise to , * furnish , 4. Revise the grammatical value of the underlined words. (Clue: they are participles), name their functions in the sentence. 5. After reading the text answer the following questions: 1. What is geology as a science? 2. How many shells does the Earth have? What are they? 3. What does the atmosphere consist of? 4. What is hydrosphere? What waters does it include? 5. What is the outer solid shell of the Earth? What is it composed of? 6. What parts of the Earth does the biosphere occupy? 6. Shortly describe each shelf enveloping the Earth. Text 2 The subject matter of geology (2800) 1. Learn the words and word combinations before reading: to be abundant in - [q'bAndqnt] - to apply - [q'plai] - , , (to) basis (pl bases) - ['beIsIs] / ['beIsJz] - , , , be concerned with - [ kqn'sWnd] - significance -[sig'nifikqns] - , , foresee - , , hazard -['hxzqd] - , mudflow margin - ['ma:dZin] - , margins of continents shallow sea - ['Sxlqu] - subdivision -['sAbdi"viZqn] - epoch - ['i:pOk] - , , fossil ['fOsl] - , ( , ) be very cautious ['kLSqs] - 2. Mind the prononciation of the following geological names: Palaeozoic ["pxliq' zqVIk] , Archeozoic ["Rki' zqVIk], Proterozoic ["prquterqu' zqVIk], Mesozoic ["mFsqu' zqVIk], Cenozoic ["sJnqu'zqVIk], Cambrian [`kxmbriqn], Ordovician ["LdqV'vISIqn], Silurian [sai'luqriqn], Devonian [de'vquniqn], Carboniferous ["kRbq'nIfqrqs], 3
4. 4. Permian ['pWmiqn], Jurassic [dZu'rxsik], Triassic [traI'xsIk], Cretaceous [krI'teISqs], Quaternary [kwq'tWnqrI] 3. Read and translate the text: Geology is the science studying the history of the earths development. Geology gives the possibility to establish how the geography of the earths surface changed in different periods of the earths existence. Studying geology one comes to know what animals and plants existed in the far off past and what changes the organic world was subjected to. The subject matter of geology is to explain the causes and regularities of all the changes. Geology is concerned with minerals, rocks, organic remains and with modern geological processes. Geology has an extremely practical significance, constituting a theoretical basis of searching and prospecting for different useful materials, all of which being rocks or minerals. Geologists work to understand the history of our planet. The better they can understand Earths history the better they can foresee how events and processes of the past might influence the future. Here are two examples: 1) The processes acting upon the Earth cause hazards such as landslides, earthquakes and volcanic eruptions. Geologists are working to understand these processes well enough to avoid building important structures where they will be damaged. If geologists learn a lot about volcanic mudflows of the past then that information can be very useful in predicting the dangerous areas where volcanic mudflows might strike in the future. Intelligent people should be cautious when considering activities or property development in these areas. 2) Geologists have worked hard to learn that oil and natural gas form from organic materials deposited along the margins of continents and in shallow seas upon the continents. They have also learned to recognize the types of rock that are deposited in these near-shore environments. This knowledge enables them to recognize potential oil and natural gas source rocks. TIME. The major subdivisions of geologic time are based on organic processes changes in animal and plant life. The time of earths crust development is divided into eras; they represent differences of life forms. Eras are subdivided into periods and this subdivision is based on the type of life existing at the time and on major geologic events like mountain building and plate tectonic movement. Periods are subdivided into epochs based on more specific and shorter time periods of life and geologic events. Then there are ages. In the course of formation of the earths crust different rocks were being developed. The names applied to the divisions of geologic time and those of the rocks 4
5. 5. were not the same, but for reach division of the time scale there is a corresponding one of the rock scale. Thus we have: TIME SCALE ROCK SCALE Era Group Period System Epoch Series age stage There are 5 eras and five corresponding groups of rocks. They are: Archeozoic era and group Proterozoic era and group Palaeozoic era and group Mesozoic era and group Cenozoic era and group Archeozoic and Proterozois eras are not abundant in organic fossils and as a rule are not subdivided into periods, epochs and ages. The Palaeozoic era and group are subdivided into Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods. The Mesozoic era has three periods: Jurassic, Triassic and Cretaceous periods. The Cenozoic era has three periods: Palaeosoic, Neogenic and Quaternary periods. Each of all these periods is represented by different forms of organic life. 4. Divide the underlined ingform words into gerund, participle and verbal noun groups. 5. See to what passive tense forms are used in the text. 6. Tell your understanding of: - the subject matter of geology; - the main tasks of geologists; - the major subdivisions of geologic time and those of the rocks. Text 3 Rocks (6400) 1. Learn the words and word combinations before reading: connote - [kO'nqut] - , 5
6. 6. specimen - ['spesimin] - , exposure - [iks'pquZq] - , ( ) igneous - ['igniqs] - crystallization - ["kristqlai'zeiSqn] - abyssal - [q'bisql] - , , adjacent geological stratum - [q'dZeisqnt] - host - [hqust] - , tungsten - ['tANstqn] - uranium - [ju'reinjqm] - granite - ['grxnit] - chromium - ['krqumjqm] - occurrence - [q'kArqns] - , texture - ['tekstSq] - , , , geometry - [dZi'Omitri] - distortion - [dis'tLSqn] - , facies - , , index mineral gneiss - [nais] - , , , valuable - ['vxljuqbl] - , sillimanite - kyanite ['kiq"nit] -, staurolite ['storq"lit] olivines - , , pyroxenes - ['pairOksJn] - amphiboles - ['amfq"bol] ( , , , , ) mica - ['maikq] - feldspar - ['feldspa:] - 2. Read and translate the text: Broadly speaking a rock is an assemblage of one or (most commonly) two or more minerals (specific chemical compounds) that form a part of the Earths solid body. A rock normally connotes an individual specimen one that can be held in ones hand or is larger but detached from its outcrop (exposure of the rocks source) so that it has visible boundaries. We know all rocks to fall into three great divisions termed: 1) sedimentary, 2) igneous, 3) metamorphic. In this text well read about two of them: igneous and metamorphic. Igneous rocks (from Latin ignis, fire) are one of the three main rock types. Igneous rocks are formed by solidification of cooled magma (molten rock). 6
7. 7. Igneous rocks that have solidified without reaching the surface are termed intrusive or abyssal. Those which have flown out on the surface as lava before solidifying are termed effusive or volcanic. Over 700 types of igneous rocks have been described, most of them formed beneath the surface of the Earths crust. These have diverse properties, depending on their composition and how they were formed. Igneous rocks make up approximately ninety-five percent of the upper part of the Earths crust, but their great abundance is hidden on the Earths surface by a relatively thin but widespread layer of sedimentary and metamorphic rocks. Igneous rocks are geologically important because: their minerals and global chemistry give information about the composition of the mantle, from which some igneous rocks are extracted, and the temperature and pressure conditions that allowed this extraction, and of other pre-existing rocks that melted; their absolute ages can be obtained from various forms of radiometric dating and thus can be compared to adjacent geological strata, allowing a time sequence of events; their features are usually characteristic of a specific tectonic environment, allowing tectonic reconstitutions; in some special circumstances they host important mineral deposits (ores): for example, tungsten, tin, and uranium are commonly associated with granites, whereas ores of chromium and platinum are commonly associated with gabbros. Typical intrusive formations are batholiths, stocks, laccoliths, sills and dikes. Igneous rocks are classified according to mode of occurrence, texture, mineralogy, chemical composition, and the geometry of the igneous body. Metamorphic rocks are the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means change in form. The protolith is subjected to heat and pressure (temperatures greater than 150 to 200 C and pressures of 1500 bars) causing profound physical and chemical change. Metamorphic rocks make up a large part of the Earths crust and are classified by texture and by chemical and mineral assemblage (metamorphic facies). They may be formed simply by being deep beneath the Earths surface, subjected to high temperatures and the great pressure of the rock layers above. They can be formed by tectonic processes such as continental collisions which cause horizontal pressure, friction and distortion. They are also formed when rock is heated up by the intrusion of hot molten rock called magma from the Earths interior. The study of metamorphic rocks (now exposed at the Earths surface following erosion and uplift) provides us with very valuable information about the temperatures and pressures that occur at great depths within the Earths crust. Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite. 7
8. 8. Metamorphic minerals are those that form only at the high temperatures and pressures associated with the process of metamorphism. These minerals include sillimanite, kyanite, staurolite, andalusite, and some garnet.Other minerals, such as olivines, pyroxenes, amphiboles, micas, feldspars, and quartz, may be found in metamorphic rocks, but are not necessarily the result of the process of metamorphism. These minerals formed during the crystallization of igneous rocks. They are stable at high temperatures and pressures and may remain chemically unchanged during the metamorphic process. However, all minerals are stable only within certain limits, and the presence of some minerals in metamorphic rocks indicates the approximate temperatures and pressures at which they were formed. 3. Determine the form of the underlined tense structures. 4. Find the gerunds in the text. 5. After reading the text answer the following questions: 1. What is a rock? 2. What are the main rock types? 3. What does the word igneous mean? 4. How many per cent of the upper part of the Earths crust do the igneous rocks make up? 5. Why are igneous rocks so geologicaly important? 6. What does the word metamorphism mean? 7. What does the study of metamorphic rocks provide us with? 8. What metamorphic minerals can you name? Text 4 Sedimentary rocks (4500) 1. Learn the words and word combinations before reading: common - ['kOmqn] - , , dolomite - ['dOlqmait] - conglomerate - [kqn'glOmqrqt] - ( ) chemogenic - [kemq'dZenIk] - clastic rock - ['klxstik] - overburden - ["quvq'bWdn] - pressure - ['preSq] - squeeze - [skwJz] - , , layer - ['leiq] - , , connate fluids - ['kOneit 'flHid] - expel - [iks'pel] - , 8
9. 9. diagenesis - ['daIqdZenisis], ( ) chemical - ['kemikql] - stratum / pl. strata - ['stra:tqm] - , , superposition - ['sju:pqpq'ziSqn] - gradation - [grq'deiSqn] - , , gap - [gxp] - , , unconformity - ['Ankqn'fLmiti] - lithification - ['litifi"keiSqn] - , equal - ['Jkwql] - size - boulder - ['bquldq] - , , cobble - ['kObl] - , ; successive - [sqksesIv] - , 2. Read and translate the text: Sedimentary rocks formed from sediments cover 75-80% of the Earths land area, and include common types such as chalk, limestone, dolomite, sandstone, conglomerate and shale. According to the agents involved in the deposition of sedimentary rocks we may have: 1) mechanically formed sediments (clastic rocks), 2) chemically formed sediments (chemogenic rocks), 3) organically formed sediments (organic rocks), 4) rocks of mixed origin. Sedimentary rocks are formed because of the overburden pressure* as particles of sediment are deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. As sediment deposition builds up, the overburden (or lithostatic) pressure squeezes the sediment into layered solids in a process known as lithification (rock formation) and the original connate fluids are expelled. The term diagenesis is used to describe all the chemical, physical, and biological changes, including cementation, undergone by a sediment after its initial deposition and during and after its lithification, exclusive of surface weathering. Sedimentary rocks are laid down in layers called beds or strata. That new rock layers are above older rock layers is stated in the principle of superposition.There are usually some gaps in the sequence called unconformities. These represent periods in which no new sediments were being laid down, or when earlier sedimentary layers were raised above sea level and eroded away. The layers may vary as to kind of material, colour, texture and thickness. 9
10. 10. The products of rock decay vary greatly in size, but when subjected to the action of running water they are sorted and graded into particles of approximately equal size in accordance with the strength of current. Grouped then according to the size beginning with the coarsest, the following names for this material may be employed: 1) boulders and cobbles (the coarsest), 2) gravel, 3) sand, 4) clay. Gradation of these into each other is very common. They are unconsolidated mechanical sediments. Sedimentary rocks contain important information about the history of Earth. They contain fossils, the preserved remains of ancient plants and animals. Coal is considered a type of sedimentary rock. Differences between successive layers indicate changes to the environment which have occurred over time. Sedimentary rocks can contain fossils because, unlike most igneous and metamorphic rocks, they form at temperatures and pressures that do not destroy fossil remains. The sedimentary rocks cover only 5% of the total of the Earths crust. All rocks disintegrate when exposed to mechanical and chemical weathering at the Earths surface. Mechanical weathering is the breakdown of rock into particles without producing changes in the chemical composition of the minerals in the rock. (ice, water, heating and cooling). Chemical weathering is the breakdown of rock by chemical reaction. In this process the minerals within the rock are changed into particles that can be easily carried away. Sedimentary rocks are economically important in that they can easily be used as construction material because they are soft and easy to cut. In addition, sedimentary rocks often form porous and permeable reservoirs in sedimentary basins in which petroleum and other hydrocarbons can be found. Notes: * overburden pressure * as to 3. Find in the text the equivalents: , , , , , , , , , . 4. Make the resume of the text. 5. Answer the question: why are sedimentary rocks so important for petroleum geophysicists? 10
11. 11. Text 5 Composition of rocks (5400) 1. Learn the words and word combinations before reading: occur - [q'kW] - , , occurrence - [q'kArqns] , crystalline structure -['kristqlain] - common - ['kPmqn] halide - [hlad] - , sulfide -['sAlfaId] - , sulfate - ['sAlfeIt] - , luster - ['lAstq] , constituent - [kqn'stItjuqnt] , transparent - [trxn'spxrqnt] - brittle - ['brItl] , . effervesce - ["efq'ves] - , substitute for -, 2. Read and translate the text: Most rocks are composed of minerals. Minerals are defined by geologists as naturally occurring inorganic solids that have a crystalline structure and a distinct chemical composition. Of course, the minerals found in the Earth's rocks are produced by a variety of different arrangements of chemical elements. A list of the eight most common elements making up the minerals found in the Earth's rocks is described in Table 1. Element Chemical Symbol Percent Weight in Earth's Crust Oxygen O 46.60 Silicon [slkn] Si 27.72 Aluminum [lu:mnm] Al 8.13 Iron [an] Fe 5.00 Calcium Ca 3.63 Sodium Na 2.83 Over 2000 minerals have been identified by earth scientists. Table 2 describes some of the important minerals, their chemical composition, and classifies them in one of nine groups. 11
12. 12. The Element Group includes over one hundred known minerals. Many of the minerals in this class are composed of only one element. Geologists sometimes subdivide this group into metal and nonmetal categories. Gold, silver, and copper are examples of metals. The elements sulfur and carbon produce the minerals sulfur, diamonds, and graphite which are nonmetallic. 12
13. 13. Table 2: Classification of some of the important minerals found in rocks. Group Typical Minerals Chemistry Elements Gold Au Silver Ag Copper Cu Carbon (Diamond and Graphite) C Sulfur S Sulfides Cinnabar [snb:] HgS Galena [gli:n] PBS Pyrite [pa()rat] FeS2 Halides Fluorite [fl()rat] CaF2 Halite [hlat] NaCl Oxides Corundum [krndm] Al2O3 Cuprite [kju:prat] Cu2O Hematite [hi:mtat] Fe2O3 Carbonates (Nitrates and Borates) Calcite [klsat] CaCO3 Dolomite [dlmat] CaMg(CO3)2 Malachite [mlkat] Cu2(CO3)(OH)2 Sulfates Anhydrite [nhadrat] CaSO4 Gypsum [dps()m] CaSO4 -2(H2O) Phosphates (Arsenates, Vanadates, Tungstates, and Molybdates) Apatite [ptat] Ca5(F,Cl,OH)(PO4) Silicates Albite [lbat] NaAlSi3O8 Augite [:dat] (Ca, Na)(Mg, Fe, Al)(Al, Si)2O6 Beryl [berl] Be3Al2(SiO3)6 Biotite [batat] K (FE, Mg)3AlSi3O10(F, OH)2 Hornblende [h:nblend] Ca2(Mg, Fe, Al)5(Al, Si)8O22(OH)2 Microcline KAlSi3O8 Muscovite [mskvat] KAl2(AlSi3O10)(F, OH)2 Olivine [lvi:n] (Mg, Fe)2SiO4 Orthoclase [:kles] KAlSi3O8 Quartz [kw:ts] SiO2 Organics Amber [mb] C10H16O 13
14. 14. The sulfides form an economically important class of minerals. Many of these minerals consist of metallic elements in chemical combination with the element sulfur. Most ores of important metals such as mercury (cinnabar - HgS), iron (pyrite - FeS2), and lead (galena - PbS) are extracted from sulfides. Many of the sulfide minerals are recognized by their metallic luster. But on account of their usual sparing occurrence in rocks only one of them, pyrite, has a special importance as a rock making mineral. The halides are a group of minerals whose principle chemical constituents are fluorine, chlorine, iodine, and bromine. Many of them are very soluble in water. Halides also tend to have a highly ordered molecular structure and a high degree of symmetry. The most well-known mineral of this group is halite (NaCl) or rock salt. The oxides are a group of minerals that are compounds of one or more metallic elements combined with oxygen, water, or hydroxyl (OH). The minerals in this mineral group show the greatest variations of physical properties. Some are hard, others soft. Some have a metallic luster, some are clear and transparent. Some representative oxide minerals include corundum, cuprite, and hematite. The carbonates consist of minerals which contain one or more metallic elements chemically associated with the compound CO3. Most carbonates are lightly colored and transparent when relatively pure. All carbonates are soft and brittle. Carbonates also effervesce when exposed to warm hydrochloric acid. Most geologists considered the Nitrates and Borates being subcategories of the carbonates. Some common carbonate minerals include calcite, dolomite, and malachite. The sulfates are a mineral group that contains one or more metallic element in combination with the sulfate compound SO4. All sulfates are transparent or translucent and soft. Most are heavy and some are soluble in water. Rarer sulfates exist containing substitutes for the sulfate compound. For example, in the chromates SO4 is replaced by the compound CrO4. Two common sulfates are anhydrite and gypsum. The phosphates are a group of minerals of one or more metallic elements chemically associated with the phosphate compound PO4. The phosphates are often classified together with the arsenate, vanadate, tungstate, and molybdate minerals. One common phosphate mineral is apatite. Most phosphates are heavy but soft. They are usually brittle and occur in small crystals or compact aggregates. The silicates are by far the largest group of minerals. Chemically, these minerals contain varying amounts of silicon and oxygen. It is easy to distinguish silicate minerals from other groups, but difficult to identify individual minerals within this group. None are completely opaque. Most are light in weight. The construction component of all silicates is the tetrahedron. A tetrahedon is a chemical structure where a silicon atom is joined by four oxygen atoms (SiO4). Some representative minerals include albite, augite, beryl, biotite, hornblende, microcline, muscovite, olivine, othoclase, and quartz. The organic minerals are a rare group of minerals chemically containing hydrocarbons. Most geologists do not classify these substances as true minerals. Note 14
15. 15. that our original definition of a mineral excludes organic substances. However, some organic substances that are found naturally on the Earth that exist as crystals resemble and act like true minerals. These substances are called organic minerals. Amber is a good example of an organic mineral. Notes: * on account of - -, , 3. Read the following sentences and say if they are taken from the text or not, if they are not correct, correct them. 1. According to geologists minerals are naturally occurring organic solids that have a crystalline structure and a distinct chemical composition. 2. The Elements Group includes over two hundred known minerals. 3. Only one of sulfide minerals has a special importance as a rock-making mineral, its mercury. 4. All carbonates are not soft and brittle. 5. Phosphates are usually brittle and occur in small crystals or compact aggregates. 4. Say: - the most common elements making up the minerals found in the Earth's rocks. - what organic minerals are. - which group of minerals is the largest one. PART 2 Text 1 Origin of Oil and Gas (4200) 1. Learn the words and word combinations before reading: decay - [dI'keI] , trap - [trxp] n , ( ), ; v , , , , , yield - [jJld] n , , ; ; (); v , , algae ['xldZJ] pl alga - kerogen - bituminous material occurring in shale and yielding oil when heated to be mature , ( ), protein - ['prqutJn] - , trigger - ['trIgq] - , , squeeze - [skwJz] - , , expel - [Ik'spel] , fracture - ['frxktSq] - , , blob - [blPb] - , tarry - ['txrI] - , , viscous - ['vIskqs] - , 15
16. 16. 2. Read and translate the text: Oil and gas are derived almost entirely from decayed plants and bacteria. Energy from the sun, which fuelled the plant growth, has been recycled into useful energy in the form of hydrocarbon compounds - hydrogen and carbon atoms linked together. Of all the diverse life* that has ever existed comparatively little has become, or will become oil and gas. Plant remains must first be trapped and preserved in sediments then be buried deeply and slowly 'cooked' to yield oil or gas. Rocks containing sufficient organic substances to generate oil and gas in this way are known as source rocks. Whether oil or gas is formed depends partly on the starting materials. Almost all oil forms from the buried remains of minute aquatic algae and bacteria, but gas forms if these remains are deeply buried. The stems and leaves of buried land plants are altered to coals. Generally these yield no oil, but again produce gas on deep burial. On burial the carbohydrates and proteins of the plant remains are soon destroyed. The remaining organic compounds form a material called kerogen. Aquatic plants and bacteria form kerogen of different composition from woody land plants. The processes of oil and gas formation resemble those of a kitchen where the rocks are slowly cooked. Temperatures within the Earth's crust increase with depth so that sediments, and kerogen which they contain, warm up as they become buried under thick piles of younger sediments. As a source rock, deposited under the sea or in a lake, becomes hotter (typically >100o C), long chains of hydrogen and carbon atoms break from the kerogen, forming waxy and viscous heavy oil. At higher temperatures, shorter hydrocarbon chains break away to give light oil and then, above about 160o C, gas. Once a source rock has started to generate oil or gas it is said to be mature. The most important products generated are gas, oil, oil containing dissolved gas, and gas containing dissolved oil which is called gas condensate. Condensate is the light oil which is derived from gas condensates to be found at high underground temperatures and pressures. Migration Much oil and gas moves away or migrates from the source rock. Migration is triggered both by natural compaction of the source rock and by the processes of oil and gas formation. Most sediments accumulate as a mixture of mineral particles and water. As they become buried, some water is squeezed out and once oil and gas are formed, these are also expelled. If the water cannot escape fast enough, as is often the case* from muddy source rocks, pressure builds up. Also, as the oil and gas separate 16
17. 17. from the kerogen during generation, they take up more space and create higher pressure in the source rock. The oil and gas move through minute pores and cracks which may have formed in the source rock towards more permeable rocks above or below in which the pressure is lower. Oil, gas and water migrate through permeable rocks in which the cracks and pore spaces between the rock particles are interconnected and are large enough to permit fluid movement. Fluids cannot flow through rocks where these spaces are very small or are blocked by mineral growth; such rocks are impermeable. Oil and gas also migrate along some large fractures and faults which may extend for great distances if as a result of movement, these are permeable. Oil and gas are less dense than the water which fills the pore spaces in rocks so they tend to migrate upwards once out of the source rock. Under the high pressures at depth gas may be dissolved in oil and vice versa so they may migrate as single fluids. These fluids may become dispersed as isolated blobs through large volumes of rock, but larger amounts can become trapped in porous rocks. Having migrated to shallower depths than the source rocks and so to lesser pressures the single fluids may separate into oil and gas with the less dense gas rising above the oil. If this separation does not occur below the surface it takes place when the fluid is brought to the surface. Water is always present below and within the oil and gas layers, but has been omitted from most of the diagrams for clarity. Migration is a slow process, with oil and gas travelling between a few kilometres and tens of kilometres over millions of years. But in the course of many millions of years huge amounts have risen naturally to sea floors and land surfaces around the world. Visible liquid oil seepages are comparatively rare, most oil becomes viscous and tarry near the surface as a result of oxidation and bacterial action, but traces of natural oil seepage can often be detected if sought. Notes: * of all the diverse life * as it often the case 3. Say what verb forms are underlined and name their functions. 4. Answer the following questions: 1. What is a source rock? 2. Under what conditions is the gas formed from algae and bacteria? 3. What is kerogen? 4. When is viscous heavy oil formed? 5. Where do oil and gas migrate? 6. Is oil less dense than the water which fills the pore space? Text 2 Trapping Oil and Gas (2750) 17
18. 18. 1. Learn the words and word combinations before reading: spill point fracture -['frxktSq] - , , bubble out ['bAbql 'aut] , break , , impervious - [im'pWvjqs] - , , ( . .) reservoir bed - ['rqzqvwa:] - - fault traps - , domed arch - [a:tS] - fold - [fquld] - , folded petroleum-bearing formation combination trap truncated - ['trANkeitid] - , , pinch - [pIntS] - . ( ; . ~ out) piercement dome [piqsi'ment 'dqum]- , spindle top 2. Read and translate the text: Oilfields and gasfields are areas where hydrocarbons have become trapped in permeable reservoir rocks, such as porous sandstone or fractured limestone. Migration towards the surface is stopped or slowed down by impermeable rocks such as clays, cemented sandstones or salt which act as seals. Oil and gas accumulate only where seals occur above and around reservoir rocks so as to stop the upward migration of oil and gas and form traps, in which the seal is known as the cap rock. The migrating hydrocarbons fill the highest part of the reservoir, any excess oil and gas escaping at the spill point where the seal does not stop upward migration. Gas may bubble out of the oil and form a gas cap above it; at greater depths and pressures gas remains dissolved in the oil. Since few seals are perfect, oil and gas escape slowly from most traps. A hydrocarbon reservoir has a distinctive shape, or configuration, that prevents the escape of hydrocarbons that migrate into it. Geologists classify reservoir shapes, or traps, into two types: structural traps and stratigraphic traps. Structural Traps Structural traps form because of a deformation in the rock layer that contains the hydrocarbons. Two examples of structural traps are fault traps and anticlinal traps. Fault Traps The fault is a break in the layers of rock. A fault trap occurs when the formations on either side of the fault move. The formations then come to rest* in 18
19. 19. such a way that, when petroleum migrates into one of the formations, it becomes trapped there. Often, an impermeable formation on one side of the fault moves opposite a porous and permeable formation on the other side. The petroleum migrates into the porous and permeable formation. Once there, it cannot get out because the impervious layer at the fault line traps it. Anticlinal Traps An anticline is an upward fold in the layers of rock, much like a domed arch in a building. The oil and gas migrate into the folded porous and permeable layer and rise to the top. They cannot escape because of an overlying bed of impermeable rock. Stratigraphic Traps Stratigraphic traps form when other beds seal a reservoir bed or when the permeability changes within the reservoir bed itself. In one stratigraphic trap, a horizontal, impermeable rock layer cuts off, or truncates, an inclined layer of petroleum-bearing rock. Sometimes a petroleum-bearing formation pinches out that is, an impervious layer cuts it off. Other stratigraphic traps are lens-shaped. Impervious layers surround the hydrocarbon-bearing rock. Still another occurs when the porosity and permeability change within the reservoir itself. The upper reaches of the reservoir are nonporous and impermeable; the lower part is porous and permeable and contains hydrocarbons. Other Traps Many other traps occur. In a combination trap, for example, more than one kind of trap forms a reservoir. A faulted anticline is an example. Several faults cut across the anticline. In some places, the faults trap oil and gas. Another trap is a piercement dome. In this case, a molten substancesalt is a common onepierces surrounding rock beds. While molten, the moving salt deforms the horizontal beds. Later, the salt cools and solidifies and some of the deformed beds trap oil and gas. Spindle top is formed by a piercement dome. Notes: * come to rest , * seal , , , . 3. Match the word combinations in the first column with their Russian equivalents in the second one. Porous sandstone Cap rock Reservoir shape Layers of rock Fault trap 19
20. 20. Faulted anticline Spill point 4. Answer the following questions: 1. Where do hydrocarbons become trapped? 2. What stops the upward migration of oil and gas? 3. What are traps? 4. When does a fault trap occur? 5. What is an anticline trap? 6. When do stratigraphic traps form? Text 3 How much oil and gas (3650) 1. Learn the words and word combinations before reading: at a profit porosity - [pL'rO siti] - , ; permeability - ["pWmjq'biliti] - , well log , rock matrix - ['meitriks] - ; core - , fluid saturation ["sxCq'reISqn] - fraction , pressure ['preSq] - ; , drive [draiv]- ; ( , ) , ( ), sealing [sJliN] fault . nonsealing drillsteam test- drilling rate log = drilling time log ; mud log , tracer 2. Read and translate the text: 20
21. 21. When deciding whether to develop a field, a company must estimate how much oil and gas will be recovered and how easily they will be produced. Although the volume of oil and gas in place can be estimated from the volume of the reservoir, its porosity, and the amount of oil or gas in the pore spaces, only a proportion of this amount will be recovered. This proportion is the recovery factor, and is determined by various factors such as reservoir dimensions, pressure, the nature of the hydrocarbon, and the development plan. More specifically, petroleum engineers have to know: -- the pore spaces of a rock (porosity). Porosity is the volume fraction of space not occupied by the rock matrix. Not only average porosity is important but also porosity distribution, both vertically and horizontally. Reservoir porosity is determined from measurements on cores and well logs using relationships that are somewhat empirical. -- how the pore spaces are interconnected (permeability), if permeability is good and the reservoir fluids flow easily, oil, gas and water will be driven by natural depletion into the well and up to the surface. -- the nature of the fluids filling the pore spaces (fluid saturation). Expansion of the gas cap and water drives oil towards the well bore. Gas and water occupy the space vacated by the oil. In reservoirs with insufficient natural drive energy, water or gas is injected to maintain the reservoir pressure. -- the energy or pressure that may cause the fluids to flow (drives). Pressure is the driving force in oil and gas production. Reservoir drive is powered by the difference in pressures within the reservoir and the well, which can be thought of as a column of low surface pressure let into the highly pressured reservoir. -- the vertical and areal distribution of reservoirs and pore-connected spaces, and -- barriers to fluid flow (sealing and nonsealing faults, stratigraphic barriers, etc.). These facts have to be determined from available information, which probably consists of: surface seismic, gravity, magnetic, and other geophysical data, borehole logs of various types, cores taken in boreholes, analyses of fluids recovered in drillstem tests, production and pressure data, specialized geophysical measurements, occasionally tracer data, and drilling rate logs, mud logs, and other well data. Well logs, geologic background, and well-to-well log correlations supplemented by seismic character studies (will be seen further) give an overall picture of the stratigraphy and stratigraphic changes across the reservoir, and pro- duction and pressure data (and occasionally tracer data) give information about the connectivity of reservoir members between wells. Surface geophysical data, while lacking the vertical resolution of borehole logs and cores, provides the only data source that gives detailed information about areal distributions. The proportion of oil that can be recovered from a reservoir is dependent on the ease with which oil in the pore spaces can be replaced by other fluids like water or gas. Tests on reservoir rock in the laboratory indicate the fraction of the original oil in 21
22. 22. place that can be recovered. Viscous oil is difficult to displace by less viscous fluids such as water or gas as the displacing fluids tend to channel their way towards the wells, leaving a lot of oil in the reservoir. Each oil and gas reservoir is a unique system of rocks and fluids that must be understood before production is planned. Of course all these facts are to be determined and calculated by a very synergistically working team of development geologists, geophysicists and petroleum engineers using all the available data to develop a mathematical model of the reservoir. Computer simulations of different production techniques are tried on this reservoir engineering model to predict reservoir behaviour during production, and select the most effective method of recovery. For example, if too few production wells are drilled water may channel towards the wells, leaving large areas of the reservoir upswept. Factors, such as construction requirements, cost inflation and future oil prices must also be considered when deciding whether to develop an oil or gas field. When a company is satisfied with the plans for development and production, they must be approved by the Government, which monitors all aspects of oil field development. 3. Explain the words: porosity, permeability, fluid saturation, sealing and nonsealing faults, drillstem tests, stratigraphic changes across the reservoir, areal distribution. 4. Answer the questions: 1. How can the volume of oil and gas in place be estimated? 2. What is the reservoir porosity determined from? 4. What gives detailed information about areal distributions? 5. What do a geologist and a geophysicist have to know about oil reservoirs? Text 4 Discovering the underground structure (6300) 1. Learn the words and word combinations before reading: pattern - ['pxtn] , , , density -['densiti] - - , , , ..; , altitude - ['xltitHd] - , , subsurface picture delineation wells - [di"lini'eiSqn] - geometric framework spatial elements - ['speiSql] - slicing validate - ['vxlideit] - 22
23. 23. laterally selected event travel time resolution , strong acoustic impedance [im'pJdqns] contrast acquisition configuration , downhole hardware - 2. Read and translate the text: Large-scale geological structures that might hold oil or gas reservoirs are invariably located beneath non-productive rocks, and in addition this is often below the sea. Geophysical methods can penetrate them to produce a picture of the pattern of the hidden rocks. Relatively inexpensive gravity and geomagnetic surveys can identify potentially oil-bearing sedimentary basins, but costly seismic surveys are essential to discover oil and gas bearing structures. Sedimentary rocks are generally of low density and poorly magnetic, and are often underlain by strongly magnetic, dense basement rocks. By measuring 'anomalies' or variations from the regional average, a three-dimensional picture can be calculated. Modern gravity surveys show a generalised picture of the sedimentary basins. Recently, high resolution aero-magnetic surveys flown by specially equipped aircraft at 70 - 100m altitude show fault traces and near surface volcanic rocks. Initially 3D seismic surveys were used over the relatively small areas of the oil and gas fields where a more detailed subsurface picture was needed to help improve the position of production wells, and so enable the fields to be drained with maximum efficiency. Nowadays 3 D seismic surveys are used for more detailed information about the rock layers, to plan and monitor the development and production of a field. The seismic information is integrated with well logs, pressure tests, cores, and other engineering/geoscience data from the discovery and delineation wells to formulate an initial field development plan. As more wells are drilled, logged, and tested, and production histories are recorded, the interpretation of the 3-D data volume is revised and refined to take advantage of the new information. Aspects of the interpretation that were initially ambiguous become clear as an understanding of the field builds, and inferences from the seismic data become more detailed and reliable. The 3-D data volume evolves into a continuously utilized and updated management tool that impacts reservoir planning and evaluation for years after the seismic survey was originally acquired. Types of 3-D Seismic Analyses 23
24. 24. The interpretations that a geophysicist might perform with 3-D seismic data can be grouped conveniently into those that examine the geometric framework of the hydrocarbon accumulation, those that analyze rock properties, and those that try to monitor fluid flow and pressure in the reservoir. These analyses affect and significantly improve decisions that must be made about volume of reserves, well or platform locations, and recovery strategy. The first general grouping is geometric framework. Its a collective term for such spatial elements as the attitudes of the beds that form the trap, the fault and fracture patterns that guide or block fluid flow, the shapes of the depositional bodies that make up a field's stratigraphy, and the orientations of any unconformity surfaces that might cut through the reservoir. By mapping travel times to selected events, displaying seismic amplitude variations across selected horizons, isochroning between events, noting event terminations, slicing through the volume at arbitrary angles, compositing horizontal and vertical sections, optimizing the use of color in displays, and using the wide variety of other interpretive techniques available on a computer workstation, a geophysicist can synthesize a coherent and quite detailed 3-D picture of a field's geometry. The second general grouping of 3-D seismic analyses involves the qualitative and quantitative definition of rock properties. Amplitudes, phase changes, interval travel times between events, frequency variations, and other characteristics of the seismic data are correlated with porosity, fluid type, lithology, net pay thickness, and other reservoir properties. The correlations usually require borehole control (well logs, cuttings, cores, etc.) both to suggest initial hypotheses and to refine, revise, and test proposed relationships. An interpreter develops a hypothesis by comparing a seismic parameter in the 3-D volume at the location of a well to the well's informa- tion, often through the intermediary of a synthetic seismogram or 2-D or 3-D seismic model. The hypothesis is then used to predict rock properties between wells, and subsequent drilling validates (or invalidates) the concept. Gas saturation in sandstone reservoirs is probably the rock property that has been most successfully mapped by 3- D seismic surveys. The presence of free gas typically lowers sharply the seismic velocity of relatively unconsolidated sandstones and creates a strong acoustic impedance contrast with surrounding rock. The contrast produces a seismic amplitude anomaly. Since the early 1970s, this "bright spot" effect has been widely exploited to detect gas saturation with standard 2-D seismic sections. When the effect occurs in 3- D volumes, gas-saturated sandstones can be accurately mapped laterally across fields at multiple producing horizons. The third general grouping of 3-D seismic analyses consists of those designed to monitor the actual flow of the fluids in a reservoir. Such flow surveillance is possible if one (1) acquires a baseline 3-D data volume at a point in calendar time, (2) allows fluid flow to occur through production and/or injection with attendant pressure/temperature changes, (3) acquires a second 3-D data volume a few weeks or months after the baseline, (4) observes differences between the seismic character of 24
25. 25. the two volumes at the reservoir horizon, and (5) demonstrates that the differences are the result of fluid flow and pressure/ temperature changes. The standard 3-D seismic data volume is acquired with source and receivers at the Earths surface. It is logistically possible to put sources and/or receivers in boreholes and to record part or all of the 3-D data volume with this downhole hardware. This approach is an active area of research. Depending on the acquisition configuration, one records various kinds and amounts of reflected and transmitted seismic energy, which can then be sorted to provide information on geometric framework, rock properties, and flow surveillance, just like surface surveys. Advantages of downhole placement are that higher seismic frequencies generally can be recorded, thereby improving resolution, and that surface-associated seismic noise and statics problems are lessened or avoided. The main disadvantages are that source and receiver plants are constrained by the physical locations of available boreholes; borehole seismology can be affected by tube waves and the like, so downhole placement is not noise-free; a borehole source cannot be so strong as to damage the well; and the logistics and economics of operating in boreholes are complex, though not necessarily always worse than operating on the surface. One can imagine a time when borehole seismic sources and receivers might be standard components of the hardware run into wells and accepted as routine and valuable devices for reservoir characterization and flow surveillance. The petroleum industry's twenty-year experience with 3-D seismic surveying is an example of a technological and economic success. Today, the investment in a 3-D survey typically results in fewer development dry holes, improved placement of drilling locations to maximize recovery, recognition of new drilling opportunities, and more accurate estimates of hydrocarbon volume and recovery rate. These outcomes improve the economics of development and production plans and make the surveys cost effective. Notes: * to take advantage of - * "bright spot" effect 2. Find the sentences in the text with the word drilling and determine its grammar form. 3. What are ing forms in the sentence below: By mapping travel times to selected events, displaying seismic amplitude variations across selected horizons, isochroning between events, noting event terminations, slicing through the volume at arbitrary angles, compositing horizontal and vertical sections, optimizing the use of color in displays, and using the wide variety of other interpretive techniques available on a computer workstation, a geophysicist can synthesize a coherent and quite detailed 3-D picture of a field's geometry. 25
26. 26. 4. Answer the questions: 1. When is 3-D seismic survey used? 2. What interpretations can the geophysicist get with 3-D seismic method? 3. What does geometric framework comprise in? 4. Can you name qualitative and quantitative definitions of the rock structure? 5. Where are the standard 3-D seismic data receivers located? 6. Why 3-D surveying method is more appreciated nowadays? ADDITIONAL READING Tasks of a Professional Geologist (11200) Statement by the National Association of State Boards of Geology (ASBOG), a non-profit organization comprised of state boards that have developed and administer national competency examinations for the licensure/registration of geologists. (in all the states in the U.S. and the territory of Puerto Rico) The following areas of professional practice contain generalized and some specific activities which may be performed by qualified, professional geologists. Professional geologists may be uniquely qualified to perform these activities based on their formal education, training and experience. Under each major heading is a group of activities associated with that specific area of geoscience practice. The major areas of professional, geologic practice include, but are not limited to: Research; Field Methods and Communications; Mineralogy; Petrology; Geochemistry; Stratigraphy; Historical, Structural, Environmental, Engineering, and Economic Geology; Geophysics; Geomorphology; Paleontology; Hydrogeology; Geochemistry; and Mining Geology and Energy Resources. These areas are specifically included in the ASBOG examinations to assure geologic competency. Again, this list represents only a cross-section of possible activities, and does not include all potential professional practice activities. Also included in this publication is a listing of "Other related activities which may be performed by qualified Professional Geologists." These activities, although not specifically geoscience in content, may be performed by a qualified, professional geologist. Research, Field Methods and Communications ! Plan and conduct field operations including human and ecological health, safety, and regulatory considerations ! Evaluate property/mineral rights ! Interpret regulatory constraints ! Select and interpret appropriate base maps for field investigations ! Determine scales and distances from remote imagery and/or maps ! Identify, locate and utilize available data sources 26
27. 27. ! Plan and conduct field operations and procedures to ensure public protection ! Construct borehole and trench logs ! Design and conduct laboratory programs and interpret results ! Evaluate historic land use or environmental conditions from remote imagery ! Develop and utilize Quality Assurance/Quality Control procedures ! Construct and interpret maps and other graphical presentations ! Write and edit geologic reports ! Interpret and analyze aerial photos, satellite and other imagery ! Perform geological interpretations from aerial photos, satellite and other imagery ! Design geologic monitoring programs ! Interpret data from geologic monitoring programs ! Read and interpret topographic and bathymetric maps ! Perform geologic research in field and laboratory ! Prepare soil, sediment and geotechnical logs ! Prepare lithological logs ! Interpret dating, isotopic, and/or tracer studies ! Plan and evaluate remediation and restoration programs ! Identify geological structures, lineaments, or fracture systems from surface or remote imagery ! Select, construct, and interpret maps, cross-sections, and other data for field investigations ! Design, apply, and interpret analytical or numerical models Mineralogy/Petrology ! Identify minerals and their physiochemical properties ! Identify mineral assemblages ! Determine probable genesis and sequence of mineral assemblages ! Predict subsurface mineral characteristics on the basis of exposures and drill holes ! Identify and classify major rock types ! Determine physical properties of rocks ! Determine geotechnical properties of rocks ! Determine types, effects, and/or degrees of rock and mineral alteration ! Determine suites of rock types ! Characterize mineral assemblages and probable genesis ! Plan and conduct mineralogic or petrologic investigations ! Identify minerals and rocks and their characteristics ! Identify and interpret rock and mineral sequences, associations, and genesis Geochemistry ! Evaluate geochemical data and/or construct geochemical models related to rocks and minerals ! Establish analytical objectives and methods ! Make determinations of sorption/desorption reactions based upon aquifer mineralogy 27
28. 28. ! Assess the behavior of dissolved phase and free phase contaminant flow in groundwater and surface water systems ! Assess salt water intrusion ! Design, implement and interpret fate and transport models ! Identify minerals and rocks based on their chemical properties and constituents Stratigraphy/Historical Geology ! Plan and conduct sedimentologic, and stratigraphic investigations ! Identify and interpret sedimentary structures, depositional environments, and sediment provenance ! Identify and interpret sediment or rock sequences, positions, and ages ! Establish relative position of rock units ! Determine relative and absolute ages of rocks ! Interpret depositional environments and structures and evaluate post-depositional changes ! Perform facies analyses ! Correlate rock units ! Interpret geologic history ! Determine and establish basis for stratigraphic classification and nomenclature ! Establish stratigraphic correlations and interpret rock sequences, positions, and ages ! Establish provenance of sedimentary deposits Structural Geology ! Plan and conduct structural and tectonic investigations ! Develop deformational history through structural analyses ! Identify structural features and their interrelationships ! Determine orientation of structural features ! Perform qualitative and quantitative structural analyses ! Map structural features ! Correlate separated structural features ! Develop and interpret tectonic history through structural analyses ! Map, interpret, and monitor fault movement ! Identify geological structures, lineaments, fracture systems or other features from surface or subsurface mapping or remote imagery Paleontology ! Plan and conduct applicable paleontologic investigations ! Correlate rocks biostratigraphically ! Identify fossils and fossil assemblages and make paleontological interpretations for age and paleoecological interpretations Geomorphology ! Evaluate geomorphic processes and development of landforms and soils ! Identify and classify landforms ! Plan and conduct geomorphic investigations 28
29. 29. ! Determine geomorphic processes and development of landforms and soils ! Determine absolute or relative age relationships of landforms and soils ! Identify potential hazardous geomorphologic conditions ! Identify flood plain extent ! Determine high water (i.e. flood) levels ! Evaluate stream or shoreline erosion and transport processes ! Evaluate regional geomorphology Geophysics ! Select methods of geophysical investigations ! Perform geophysical investigations in the field ! Perform geological interpretation of geophysical data ! Design, implement, and interpret data from surface or subsurface geophysical programs including data from borehole geophysical programs ! Identify potentially hazardous geological conditions by using geophysical techniques ! Use wire line geophysical instruments to delineate stratigraphic/lithologic units ! Conduct geophysical field surveys and interpretations, e.g. petrophysical wellbore logging devices, seismic data (reflection and refraction), radiological, radar, remote sensing, electro-conductive or resistive surveys, etc. Includes delineation of mineral deposits, interpretation of depositional environments, formation delineations, faulting, salt water contaminations-intrusion, contaminate plume delineations and other ! Identify and delineate earthquake/seismic hazards ! Interpret paleoseismic history Hydrogeology/Environmental Geochemistry ! Plan and conduct hydrogeological, geochemical, and environmental investigations ! Design and interpret data from hydrologic testing programs including monitoring plans ! Utilize geochemical data to evaluate hydrologic conditions ! Develop and interpret groundwater models ! Apply geophysical methods to analyze hydrologic conditions including geophysical logging analysis and interpretation ! Determine physical and chemical properties of aquifers and vadose zones ! Define and characterize groundwater flow systems ! Develop water well abandonment plans including monitoring and public water supply wells ! Develop/interpret analytical, particle tracking and mass transport models ! Design and conduct aquifer performance tests ! Define and characterize saturated and vadose zone flow and transport ! Evaluate, manage, and protect groundwater supply resources ! Potentiometric surface mapping and interpretation 29
30. 30. ! Design and install groundwater exploration, development, monitoring, and pumping/injection wells ! Develop groundwater resources management programs ! Plan and evaluate remedial-corrective action programs based on geological factors ! Evaluate, predict, manage, protect, or remediate surface water or groundwater resources from anthropogenic (man's) environmental effects ! Characterize or determine hydraulic properties ! Interpret dating, isotopic, and/or tracer surveys ! Determine chemical fate in surface water and groundwater systems ! Make determinations of sorption/desorption reacti ons based upon aquifer mineralogy ! Assess the behavior of dissolved phase and free phase contaminant flow in groundwater and surface water systems ! Assess and develop well head protection plans and source water assessment delineations Engineering Geology ! Provide geological information and interpretations for engineering design ! Identify, map, and evaluate potential seismic and othergeologic-geomorphological conditions and/or hazards ! Provide geological consultation during and after construction ! Develop and interpret engineering geology investigations, characterizations, maps, and cross sections ! Evaluate materials resources ! Plan and evaluate remediation and restoration programs for hazard mitigation and land restoration ! Evaluate geologic conditions for buildings, dams, bridges, highways, tunnels, excavations, and/or other designed structures ! Define and establish site selection and evaluation criteria ! Design and implement field and laboratory programs ! Describe and sample soils for geologic analyses ! Describe and sample soils for material properties/geotechnical testing ! Interpret historical land use, landforms, or environmental conditions from imagery, maps, or other records ! Conduct geological evaluations for surface and underground mine closure and land reclamation ! Laboratory permeability testing of earth and earth materials Economic Geology, Mining Geology, and Energy Resources (including metallic and non-metallic ores/minerals, petroleum and energy resources, building stones/materials, sand, gravel, clay, etc.) 30
31. 31. ! Plan and conduct mineral, rock, hydrocarbon, or energy resource exploration and evaluation programs ! Implement geologic field investigations on prospects ! Perform geologic interpretations for rock, mineral, and petroleum deposit evaluations, resource assessments, and probability of success ! Perform economic analyses/appraisals ! Provide geologic interpretations for mine development and production activities ! Provide geologic interpretations and plans for abandonment, closure, and restoration of mineral and energy development or extraction operations ! Identify mineral deposits from surface and/or subsurface mapping or remote imagery ! Predict subsurface mineral or rock distribution on basis of exposures, drill hole, or other subsurface data ! Evaluate safety hazards associated with mineral, petroleum, and/or energy exploration and development ! Determine potential uses and economic value of minerals, rocks, or other natural resources Other related activities which may be performed by qualified Professional Geologists ! Implement siting plans for the location of lagoons and landfills ! Environmental contaminant isocontour mapping ! Conduct water well inventories ! Determine geotechnical aquifer parameters ! Land and water (surface and ground water) use utilized in planning, land usage, and other determinations ! Determine sampling parameters and provide field oversight. Emergency response activities and spill response planning including implementation and coordination with local, state, and federal agencies ! Develop plans and methods with law enforcement, fire, emergency management agencies, toxicologists and industrial hygienists to determine methods of protection for public health and safety ! Provide training related to hazardous materials and environmental issues related to hazardous materials ! Develop plans and methods with biologists for protection of wildlife during spill events ! Prepare post spill assessments and remediation plans ! Develop and implement site safety plans and environmental sampling plans ! Provide educational outreach related to geological, geotechnical, hydrologic, emergency response and other activities ! Respond to natural disaster events (i.e. floods, earthquakes, etc.) for protection of human health and the environment ! Participate in pre-planning for spill events in coastal or other environmentally sensitive environments 31
32. 32. ! Develop resource(s) and infrastructure vulnerability assessment plans and reports related to potable and non-potable water supplies, waste water treatment facilities, etc. Some more information about rocks (3800) Dykes are intersecting veins. In inclination dykes may vary from vertical to horizontal. Sometimes we may observe them extend, outward from larger masses of intruded rocks. Effusive or volcanic rocks occur in the forms of domes, sheets and flows. Domes are the names of arched accumulations of lava solidified in the form of beds similar to those of sedimentary rocks. Sheets are formed on the surface from quiet outwelling of highly molten materials through a) localized opening or volcanic vents and hence connected with volcanic eruptions or b) from fissures not connected with volcanic eruptions. Sheets are similar in form to sedimentary strata and extend to large areas. Flows are formed in the same manner as sheets but they fill negative reliefs such as valleys and flumes. Flows are much smaller in size than sheets. Igneous rocks are characterized by a holocrystal line (or granular-crystalline), glassy and porphyritic structure. Igneous rocks are subdivided according to their chemical composition. Based upon the silicon oxide content the rocks are divided into ultra acid, acid average, basic and ultra basic. The amount of silica present exercises an important influence on the crystallization of the magma. The many hundreds of analyses that have been made of igneous rocks show them to contain the following principal oxides, silica, alumina, iron oxides, ferric, ferrous, magnesia, lime, soda, and potash. These principal oxides as composing igneous rocks do not exist as free oxides, excepting a few cases with but a few exceptions only in small amounts. TEXTURE OF IGNEOUS ROOKS. By texture of an igneous rock is meant size, shape and manner of aggregation of its component minerals. It is considered to be an important means of determining the physical conditions under which the rock was formed at or near the surface or at some depth below and hence is recognized to be one of the important factors in the classification of igneous rocks. Some rocks are sufficiently coarse-grained in texture for the principal mineral to be readily distinguished by unaided eye. In others their minerals are too small to be seen even with the aided eye. There are also those in which no minerals appeared to have crystallized. Instead the magma has solidified as a glass. KINDS OF TEXTURE. Expressing so closely the conditions under which rock magmas solidify the texture is recognized to be an important property of rocks and one of the principal factors in their classifications. 32
33. 33. In megascopic description of igneous rocks five principal textures were reported to exist. They are glassy, dense or felsitic, porphyritic, granitoid and fragmental. According to the size of mineral grains we may recognize: 1) fine-grained ; 2) medium-grained; 3) coarse-grained rocks. DESCRIPTION OF SOME IGNEOUS ROOKS. Granites are known to be composed of feldspar and quartz usually with mica or hornblende, rarely pyroxene. The chemical composition of granite is now regarded to be of less economic importance than the mineral composition. PHYSICAL PROPERTIES. The usual colour of granite is reported to be some shade of grey though pink or red varieties are likely to occur depending chiefly upon that of the feldspar and the proportion of the feldspar to the dark minerals. Specific gravity ranges from 2.65 to 2.75. The percentage of absorption is very small. Crushing strength is very high ranging from 15.000 to 20.000 pounds per square inch (psi). These properties render the rock especially desirable for building purposes. DIORITE. MINERAL COMPOSITION. The diorites are granular rocks which are known to be composed of plagioclass as the chief feldspar and hornblende or biotite or both. Augite is likely to be present in some amount and some ortho - class occurs in all diorites. The name diorite is applied to those granular rocks in which hornblende is found to equal or exceed feldspar in amount. Because of the fine-grained texture it is not possible in many cases to determine by megascopic examination the dominant feldspar. CHEMICAL COMPOSITION. The most important points to be observed in the chemical composition of normal diorites are lower silica content but notably increased percentages of the bases, iron, lime and magnesia over the granites. PHYSICAL PROPERTIES. Diorites are usually of a dark or greenish colour, sometimes almost black depending upon the colour of hornblende and its proportion to feldspar. They have a higher specific gravity than granites, ranging from 2.82 to 5.0. They show a high compressive strength and a low percentage of absorption. More information about sedimentary rocks (4500) Organic sedimentary rocks are given this name because of their having been formed partly or wholly from organic material. The most widely spread are: limestones, chalk, dolomites, radio-larites, spongiolites, tripoli, caustobioliths. Sedimentary rocks of chemical origin include a series of deposits owing to their origin processes that are chemical in character and formed chiefly by concentration through evaporating aqueous solutions, changes of temperature, loss of carbon 33
34. 34. dioxide, etc., aided more or less in some cases by the action of organic life (plants and animals) and resulting in precipitating insoluble salts. These may be subdivided into carbonates, siliceous rocks, ferrugineous rocks (iron ores), sulphates and haloids. Sedimentary rocks of mixed origin include the rocks which may be formed: 1) partly from clastic and partly from organic material; 2) from clastic material and that of chemical origin; 3) from the material of chemical or of organic origin; 4) from materials of clastic, organic and chemical origin. Their being of mixed origin results in some properties similar to those of rocks of organic, chemical and clastic origin. The term "metamorphic", when broadly applied, includes any change or alteration that any rock has undergone. It involves changes that are both physical and chemical, and the rock so altered may have been originally of sedimentary or igneous origin. The alteration includes changing in mineral composition or texture or both. This change being sometimes very great obscures the primary characters of the original rock, rendering the possibility of defining the source rock almost impossible. Chemical composition of metamorphic rocks varies greatly because of the source material having been of widely different composition. The chemical composition of many rocks is not greatly changed during the process of metamorphism; hence, metamorphosed igneous and sedimentary rocks frequently show the composition characteristic of their class. Chemical analysis therefore frequently forms an important criterion for discriminating between metamorphose sedimentary and igneous rocks. Mineral composition of metamorphic rocks being dependent on chemical composition leads to wide variations in mineral content of metemorphic rocks. It has been shown that certain, minerals such as the feldspathoids (nepheline and sodalite) are characteristic of igneous rocks. Likewise there are certain minerals which are considered to be characteristic of metamorphic rocks. Mineral composition often becomes at important criterion in distinguishing metamorphosed sedimentary from metamorphosed igneous rocks. Metamorphic rocks include: marls, clayey limestones, arenaceous limestones, and others. As has been stated before, igneous rocks occur in the form of batholiths, laccoliths, stocks, dykes; etc. The mode of occurrence of metamorphic rocks depends on the kind of rocks they have been formed from. We shall speak mostly about sedimentary rocks because of their being of more practical importance. The principal morphological units of sedimentary rocks are beds (layers). The layers may vary as to kind of material, colour, texture and thickness. Variations in thickness of individual layers may range from a very smell fraction of an inch up to one hundred feet and more. If we use the terms "layer" or "bed" which are synonym, we refer to thicker divisions. If the divisions were thinner we should use the term "lamina". "Stratum" is generally applied to a single bed or layer of rock while a group of beds deposited in sequence one above another and during the same period of 34
35. 35. geologic time is known as a formation or suite. The formation may include beds of both homogeneous and heterogeneous rocks. Every bed or suite of beds has thickness. We distinguish a true thickness true thickness, a horizontal thickness and vertical thickness. The true thickness is the length of the perpendicular line from any point on the top of the bed to the bottom of this bed. The horizontal thickness is the length of the horizontal line from any point on the top to the bottom drawn across. The vertical thickness is the length of the vertical line drawn from any point on the top to the bottom. Beds of rocks may be observed in outcrops. The outcrops occur as artificial or natural ones. As a rule the primary occurrence of sediments is almost horizontal. If there is any displacement as to primary position of beds, we call this displacement a dislocation or faulting. If the dislocation is not accompanied by discontinuity, it is called a plicative dislocation should there-be any discontinuity, a disjunctive dislocation" would result. Both plicative and disjunctive dislocations are the result of movements of the earth's crust. Had there been no crustal movements, no dislocations would have occurred. If the crustal movements are horizontal or nearly so, plicative dislocations result; if they are vertical or approximately vertical, the dislocations will be disjunctive. Plicative dislocations are often accompanied by disjunctive ones, or vice versa. The occurrence of beds may be conformable and unconformable, of gentle dip and folded, transgressive etc. The position of the bed in space is defined by the elements of its occurrence, that is, by strike and dip. A strike of a bed is the direction of the line of its intersection with a horizontal plane. A dip of the bed is its inclination as to the horizontal plane. Geophysical survey methods (after G. Pratt) (2000) Survey method Measured parameter Physical Property Major Applications Potentials Gravity Spatial variations in the local strength of the gravitational field of the Earth Local variations in density Mapping of regional structures, sedimentary basins, salt diapers, plutonic intrusions delineation, sand and gravel deposits, depth to bedrock Magnetics Spatial variations in Local variations in Mapping of regional 35
36. 36. the local strength of the geomagnetic field susceptibility and remanence structures, airborne surveys, igneous intrusions, sea floor spreading, salt structures, mineral deposits, buried environmental hazards, archeology Electrical Resistivity Earth resistance (applied voltage / measured current) Electrical resistivity (conductivity) Mineral prospecting, engineering and hydrogeology, contaminant mapping, construction site investigation, groundwater Induced polarization (IP) Voltage decay, or frequency dependent resistance Electrical capacitance Detection of disseminated mineral deposits, aquifer mapping, contaminant mapping Self-potential (SP) Natural electric potential Electro-chemical activity Mineral prospecting, graphite detection, hydrogeology, geothermal studies Electromagnetic (EM) Secondary (induced) electromagnetic fields Electrical conductivity and inductance Deep mineral prospecting, airborne surveys, conducting faults, groundwater studies, detection of underground pipes and cables, agricultural studies Ground Penetrating Radar Traveltimes, amplitudes, waveforms of reflected electromagnetic pulse Electrical conductivity, radar image Shallow sedimentary structures, water table detection, bedrock mapping, mapping of hydrocarbon contaminants Seismic Earthquake, Microseismic Location of earthquake, traveltime of elastic waves Compressional, shear velocity, fracture location Earth mapping at all scales from global to mine excavation Refraction Traveltimes, amplitudes, waveforms of refracted elastic waves Compressional, shear wave velocities Crustal scale to engineering scale mapping of rock types, structural boundaries, foundations, hydrogeology Reflection Traveltimes, Compressional, Oil and gas exploration, site 36
37. 37. amplitudes, waveforms of reflected elastic waves shear wave contrasts, density contrasts, seismic image surveying, bedrock mapping, detection of shallow faults and cavities. Preparing to Drill (4100) Once the site has been selected, it must be surveyed to determine its boundaries, and environmental impact studies may be done. Lease agreements, titles and right-of way accesses for the land must be obtained and evaluated legally. For off-shore sites, legal jurisdiction must be determined. Once the legal issues have been settled, the crew goes about preparing the land: 1. The land is cleared and leveled, and access roads may be built. 2. Because water is used in drilling, there must be a source of water nearby. If there is no natural source, they drill a water well. 3. They dig a reserve pit, which is used to dispose of rock cuttings and drilling mud during the drilling process, and line it with plastic to protect the environment. If the site is an ecologically sensitive area, such as a marsh or wilderness, then the cuttings and mud must be disposed offsite -- trucked away instead of placed in a pit. Once the land has been prepared, several holes must be dug to make way for the rig and the main hole. A rectangular pit, called a cellar, is dug around the location of the actual drilling hole. The cellar provides a work space around the hole, for the workers and drilling accessories. The crew then begins drilling the main hole, often with a small drill truck rather than the main rig. The first part of the hole is larger and shallower than the main portion, and is lined with a large-diameter conductor pipe. Additional holes are dug off to the side to temporarily store equipment -- when these holes are finished, the rig equipment can be brought in and set up. Setting Up the Rig Depending upon the remoteness of the drill site and its access, equipment may be transported to the site by truck, helicopter or barge. Some rigs are built on ships or barges for work on inland water where there is no foundation to support a rig (as in marshes or lakes). Once the equipment is at the site, the rig is set up. Here are the major systems of a land oil rig: Power system large diesel engines - burn diesel-fuel oil to provide the main source of power electrical generators - powered by the diesel engines to provide electrical power Mechanical system - driven by electric motors 37
38. 38. hoisting system - used for lifting heavy loads; consists of a mechanical winch (drawworks) with a large steel cable spool, a block-and-tackle pulley and a receiving storage reel for the cable turntable - part of the drilling apparatus Rotating equipment - used for rotary drilling swivel - large handle that holds the weight of the drill string; allows the string to rotate and makes a pressure-tight seal on the hole kelly - four- or six-sided pipe that transfers rotary motion to the turntable and drill string turntable or rotary table - drives the rotating motion using power from electric motors drill string - consists of drill pipe (connected sections of about 30 ft / 10 m) and drill collars (larger diameter, heavier pipe that fits around the drill pipe and places weight on the drill bit) drill bit(s) - end of the drill that actually cuts up the rock; comes in many shapes and materials (tungsten carbide steel, diamond) that are specialized for various drilling tasks and rock formations Casing - large-diameter concrete pipe that lines the drill hole, prevents the hole from collapsing, and allows drilling mud to circulate Circulation system - pumps drilling mud (mixture of water, clay, weighting material and chemicals, used to lift rock cuttings from the drill bit to the surface) under pressure through the kelly, rotary table, drill pipes and drill collars pump - sucks mud from the mud pits and pumps it to the drilling apparatus pipes and hoses - connects pump to drilling apparatus mud-return line - returns mud from hole shale shaker - shaker/sieve that separates rock cuttings from the mud shale slide - conveys cuttings to the reserve pit reserve pit - collects rock cuttings separated from the mud mud pits - where drilling mud is mixed and recycled mud-mixing hopper - where new mud is mixed and then sent to the mud pits Derrick - support structure that holds the drilling apparatus; tall enough to allow new sections of drill pipe to be added to the drilling apparatus as drilling progresses Blowout preventer - high-pressure valves (located under the land rig or on the sea floor) that seal the high-pressure drill lines and relieve pressure when necessary to prevent a blowout (uncontrolled gush of gas or oil to the surface, often associated with fire) 38
39. 39. Anatomy of an oil rig Drill-mud circulation system 39
40. 40. , , . : 2MnO2 [tu:molikju:lz v em en ou tu:] + , , : + hydrogen ion [haidridZn ain] univalent positive hydrogen ion [ju:niveilnt pozitiv hai- dridZn ain] Cu++ divalent positive cuprum ion [daiveilnt poztiv kju:prm ain] Al +++ trivalent positive aluminium ion [tri: veilnt poztiv ,ljuminijm ain] Cl negative chlorine ion [negtiv klo:ri:n ain] negative univalent chlorine ion [negtiv ju:niveilnt klo:ri:n ain] : : .. Cl :Cl : :Cl:C:Cl Cl C Cl [si: si: el fo:] :Cl: Cl = :: : .. :::::: == [si: ou tu:] + : plus, and together with = : give form : give, pass over to lead to ( 3) : forms is formed from ( 8) form are formed ( 7: . .) ( ) round brackets [raund brkits] [ ] square brackets [skw brkits] (x) multiplication sign ( ) ( 10) 40
41. 41. 1. 4KCl [fo:molikju:lz v ke si: el] 2. 4HCl + O2 = 2Cl2 + 2H2O [fo:molikju:lz v eit si: el plAs ou tu: giv tu: molikju:lz v si: el tu: nd tu: molikju:lz v eit tu: ou] 3. Zn + CuSO4 = Cu + ZnSO4 [zed en plAs si: ju: es ou fo: giv si: ju: plAs zed en es ou fo:] 4. PCl3 + 2Cl PCl5 [pi: si: el ri: plAs tu: molikju:lz v si: el giv pi: si: el faiv] 5. H2 + J2 2HJ [eit tu: plAs dZei tu: fo:m nd a: fo:md frm tu: molikju:lz v eit dZi] 6. C2H2 + H2O CH3CHO [si: tu: eit tu: plAs eit tu: ou giv si: eit ri: si: eit ou] 7. N2 + 3H2 2NH3 [en tu: plAs ri: molikju:lz v eit tu: fo:m nd a: fo:md frm tu: molikju:lz v en eit ri: ] 8. AcOH AcO- + H+ [ei si: ou eit fo:mz nd iz fo:md frm ei si: negtiv oksidZn ain plAs haidrodZn ain ] H | H H C H [si: eit fo:] | H 9. Al2 (SO4)3 [ei el tu: raund brkits oupnd es ou fo raund brkits klousd ri: ] 10. ab=c a multiplied by b equals c Contents: 41
42. 42. Part 1 Text 1 Geology (4500) Text 2 The subject matter of geology (2800) Text 3 Rocks (6400) Text 4 Sedimentary rocks (4500) Text 5 Composition of rocks (5400) Part 2 Text 1 Origins of Oil and Gas (4200) Text 2 Trapping Oil and Gas (2750) Text 3 How much oil and gas (3650) Text 4 Discovering the underground structure (6300) Texts for additional reading 42