oil shaleextraction
TRANSCRIPT
SHALE-OIL EXTRACTION Increasing Indonesia Energy Production
Adi Danu SaputraTeknik Geologi Universitas Diponegoro
ABSTRACTOil shale, also known as kerogen shale, is an organic-rich fine-grainedsedimentary rock containing kerogen (a solid mixture of organic chemicalcompounds) from which liquid hydrocarbons called shale oil can beproduced to generate energy. Shale oil is a substitute for conventionalcrude oil though in its practice it has produced environmental impactand its cost production is higher than conventional crude oil. Shale-oilextraction is a process in which oil-shale is extracted. This processconverts kerogen in oil shale into shale oil by pyrolysis,hydrogenation, or thermal dissolution. The process of extraction can bedone either in situ or ex situ. The resultant shale oil is used as fuel oil asa unconventional oil. Based on H.W Parker invention in 1967 the in situprocess involve heater of subterranean oil-shale bearing formation usingwell injection, the extracted fluid then centrifuged and dissolved to becarried to surface. Whereas the in situ process invented by Michael Partinvolves heated-oil miscible fluids using paired injection well. Ex situprocess involves some process such as internal combustion, hot recycledsolid and conduction wall based on Alberta Taciuk Processor. Fisheressay said that the extraction technology can recover up to 60% ofkerogen. Shale-oil can also be a new source for refinery andpetrochemical industry which rely on oil and oil product.
Keywords: kerogen, shale-oil extraction, in situ process, ex situ process.
INTRODUCTION
Shale is sedimentary rock withrelatively high content oforganic matter. The organicmatter or kerogen of shale isbelieved to exist betweenparticle of anorganic matter andsome portion of thereof maybedirectly or chemically bounded tomineral constituents. Theinability of the usual organicsolvent to dissolve kerogen fromshale directly and the failure ofusual ore-dressing technique
(sink-float) to result inappreciable enrichment in organicmatter is believed to indicatethat the most of the kerogen isheld to the inorganic matter ofthe shale by bonds stronger thanmere physical adsorption. The U.S. Geological Survey (USGS)defines oil shale as "organic-rich shale that yieldssubstantial quantities of oil byconventional methods ofdestructive distillation of thecontained organic matter, whichemploy low confining pressures in
a closed retort system." (Duncanand Swanson, 1965). Oil-shalesrocks are special amongorganogenous rocks not only intheir genesis and composition butalso in their role as power andchemical industry raw materials.They differ from humouscaustobioliths by higher hydrogencontent in their organic matterand consequently by higher yieldof liquid organic products (shaleoil) from their thermaldecomposition. This is why oilshales are regarded as apotential source for producingsynthetic liquid fuels and rawmaterials for chemical industry.On the other hand, they areusually rich in mineral matterand for complex utilization ofoil shales the problems connectedwith the utilisation of theirminerals components must besolved. The existing datapresented at the 27thInternational Geological Congress(1984) put them at 11.5 × 1012tonnes or 550 billion tonnes ofshale oil. Oil shale deposits arefound on all continents; thereserves are more evenlydistributed compared to crude oiland for many countries. Theactuality of the use of oilshales has always depended on theoil market; as the reserves ofthe latter are being depleted,the oil shales become more andmore important as a source ofenergy and as alternative sourceof liquid fuels and chemical rawmaterials. The current high oilprices have revived the interestin oil shale. The Energy PolicyAct of 2005 (EPACT) identifiedoil shale as a strategically
important domestic resource,among others, that should bedeveloped. In Indonesia, shale isone of the commonest rocks foundether in outcrop and borehole. Atthe present time, the increase ofoil price at approximately US$100 per barrel is an incentivefor the Indonesian Government toconsider alternative energieswhich may be help to raiseenergies production besidesconventional oil and gas. So thistechnology should be investigatedfor development in Indonesia.There are now some commercialprocess of extraction and somemany more conditional extractiontechnologies around the world.
METHOD
This study is an overview of bookliteratures, journals, andinternet article.
DISCUSSION
Understanding of oil-shaleextraction
Shale oil extraction is anindustrial process forunconventional oil production.This process converts kerogen inoil shale into shale oil bypyrolysis, hydrogenation, orthermal dissolution. Theresultant shale oil is used asfuel oil or upgraded to meetrefinery feedstock specificationsby adding hydrogen and removingsulfur and nitrogen impurities.Shale oil extraction is usuallyperformed above ground (ex situprocessing) by mining the oil
shale and then treating it inprocessing facilities. Othermodern technologies perform theprocessing underground (on-siteor in situ processing) byapplying heat and extracting theoil via oil wells. This processconverts kerogen in oil shaleinto shale oil by pyrolysis,hydrogenation, or thermaldissolution. Pyrolysis(temperatures above 900°F)thermally breaks down (cracks)the kerogen to release thehydrocarbons and then cracks thehydrocarbons into lower-weighthydrocarbon molecules. Because ofits insolubility, the organicmatter must be retorted attemperatures of above 900 F todecompose it into shale oil andgas. Two basic retortingprocesses were developed earlyon-- aboveground retorting andunderground, or in situ,retorting.
Origin of Oil-Shale
Oil shales were deposited in awide variety of environments,including freshwater to salineponds and lakes, epicontinentalmarine basins and relatedsubtidal shelves. They were alsodeposited in shallow ponds orlakes associated with coal-forming peat in limnic andcoastal swamp depositionalenvironments. It is notsurprising, therefore, that oilshales exhibit a wide range inorganic and mineral composition.Most oil shales were formed underanaerobic conditions thatprecluded the presence ofburrowing organisms that could
have fed on the organic matter.Many oil shales show well-laminated bedding attesting to alow-energy environment, free ofstrong currents and wave action.Most oil shales contain organicmatter derived from varied typesof marine and lacustrine algae,with some debris of land plants,depending upon the depositionalenvironment and sediment sources.Bacterial processes were probablyimportant during the depositionand early diagenesis of most oilshales. Such processes couldproduce significant quantities ofbiogenic methane, carbon dioxide,hydrogen sulphide, and ammonia.These gases in turn could reactwith dissolved ions in thesediment waters to formauthigenic carbonate and sulphideminerals such as calcite,dolomite, pyrite, and even suchrare authigenic minerals asbuddingtonite, an ammoniumfeldspar. The organic matter (OM)is mixed with varied amounts ofmineral matter (MM) consisting offine-grained silicate andcarbonate minerals. The ratio ofOM: MM for commercial grades ofoil shale is about 0.75:5 to1.5:5.
World History of Oil-ShaleDevelopment
Small scale oil shale industriesdeveloped in Europe in the 19th
Century and have operated atvarious times in parts of Europe,Africa, Asia, and Australia.China has operated an oil shaleplant for a number of yearsproducing approximately 40,000barrels of oil per day. Oil shale
has been burned directly as asolid fuel for domestic purposesand small industrial operations.Estonia has used oil shale insolid form for fuel for electricpower generation. Oil shaleoperations in Sweden andScotland, each producing 500 to700 thousand barrels per year,were closed in 1962. (Duncan andSwanson, 1965). Small oil shaledeposits of Triassic age havebeen mined for several centuriesin northern Italy, Austria, andSwitzerland, to produce ichthyol,so-named because the beds arerich in fish remains. Long beforethe United States’ increasingdependence on imported crude oilbecome apparent, oil shale beganattracting the interest of somemajor petroleum companies: Exxon,Occidental Petroleum, and UnionOil, among others.
In-situ Process
In situ technologies is a processwhich heat oil shale subterraneanby injecting hot fluids or gases(oil solvents) into the rockformation such as gas oil usinginjection well followed bythermal conduction and convectionto distribute heat through thetarget area. Shale oil is thenrecovered through productionwells drilled into the formation.These technologies arepotentially able to extract moreshale oil from a given area ofland than conventional ex situprocessing technologies, as thewells can reach greater depthsthan surface mines. In-situprocess is applicable anywhere toany oil-shale which contain or
assays at least twenty gallons ofshale oil per ton of shale. Someof in-situ process will beexplained here.
H.W Parker Method (PhillipsPetroleum Company)
This method use conduction wallsto transfer heat. Theseconduction walls are heating pipeplanted within oil-shale rock. Inaddition to conduction wallsthere are also a production wallswhere produced oil mixture isaccumulated. The produced oilmixture is then placed incentrifuge to disintegratemineral matter and solid matterof the oil. Oil produced in thecooker is recovered thru a linewhile mineral matter and solidmatter are recovered thru line.The produced oil may be used as afuel for any desired purposes.Separated oil from centrifuge ispassed thru line into adistillation column. Thisdistillation column isconventional distillation columnfrom which a various fractionsare recovered in conventionalmatter such as gaseoushydrocarbon, gasoline, cycle oil,and residuum (topped crude). Thegas oil is turned back intoconduction wall to operationalpurpose. (Figure 1).
Heated Oil-Miscible Fluid (ShellOil Company)
In this method, shale is heatedin moderately low temperature butrelatively long heating period(400 to 600 F) using oil misciblefluids until a significant
proportion of organic componentsof the heated oil-shale areconverted to oil-shale derivedfluidizable materials. It hasbeen found that kerogen in anoil-shale formation undergoes alow-temperature conversion tofluidizable materials capable ofbeing displaced, dissolved, orentrained in a hot fluid thatcontact the oil-shale. Thismethod basically has productionwells and injection well.Injection well is used tocirculate heated fluid. The zonebetween 2 wells must be apermeable zone wherein a fractureis located to establish acommunication between 2 well. Thefractured and permeable zone canbe made by hydraulic fracturing.Produced matter is fluidizablematerials and recycle product ofheated fluid. It has been foundthat in this process asignificant amount of fluidizablematerial is produced in thepresence of hydrogen sulphide. Soin this process, hydrogensulphide plus hydrogen witheither fluid is heated to effectthe heating and the fluid whichis circulated to displace orextract the oil. Heated fluids iscirculated back to injection wellwithin subterranean shale rocks.(Figure 2).
Wall Conduction (Shell In-situConverting Process)
Wall conduction in situtechnologies use heating elementsor heating pipes placed withinthe oil shale formation. TheShell in situ conversion process(Shell ICP) uses electrical
heating elements for heating theoil shale layer to between 650and 700 °F (340 and 370 °C) overa period of approximately fouryears. The processing area isisolated from surroundinggroundwater by a freeze wallconsisting of wells filled with acirculating super-chilled fluid.Horizontal and vertical wellsapply steam to the oil shaledeposit and vertical wellsrecover the oil. Heat is suppliedby combustion of natural gas orpropane in the initial phase andby oil shale gas at a later stagewhich is recycled to injectionwell. (Figure 3)
Ex-situ Process
Ex-situ process is a process whichheat above ground oil-shale rockto convert organic material intooil product. The process ofpyrolysis, hydrogenation andthermal dissolution is broughtabout above ground in afacilities complex to treat oil-shale raw material. Ex-situprocess include internalcombustion, hot recycled solidand conduction wall. Some ofthese technique will be explainedhere.
Internal Combustion
In this technique, oil-shale rawmaterial is feed in a verticalshaft where these three basicprocess occur. Some materials isburned within to supply heat forpyrolysis. Typically raw oilshale particles between 12millimetres (0.5 in) and 75millimetres (3.0 in) in size are
fed into the top of the retortand are heated by the rising hotgases, which pass through thedescending oil shale, therebycausing decomposition of thekerogen at about 500 °C (932°F) . Shale oil mist, evolvedgases and cooled combustion gasesare removed from the top of theretort then moved to separationequipment. Condensed shale oil isaccumulated, while non-condensable gas is recycled andused to carry heat up the retortagain. In the lower part of theretort, air is injected for thecombustion which heats the spentoil shale and gases to between700 °C (1,292 °F) and 900 °C(1,650 °F). Internal combustiontechnologies such as the ParahoDirect are thermally efficient,since combustion of char on thespent shale and heat recoveredfrom the shale ash and evolvedgases can provide all the heatrequirements of the retort. Thistechnologi can achieve 80-90% ofFischer assay yield. (Figure 4).
Opportunities for Development
A U.S 2010 report found that thedevelopment of oil-shale presentsignificant opportunities for thecountry. The potentialopportunities relating to oil-shale development includeincreasing domestic oilproduction and socioeconomicbenefit. There are also someopportunities which impact otherindustries such as refinery andpetrochemical plants, OPECcountries consideration at thismoment of raising oil price, and
net importer countries of oilwith potential oil-shaleresource.
Increasing domestic oilproduction: Oil shaleformations could go a longway toward satisfying thefuture oil demands. TheGreen River Formation—anassemblage of over 1,000feet of sedimentary rocksthat lie beneath parts ofColorado, Utah, and Wyoming—contains the world’slargest deposits of oilshale. USGS estimates thatthe Green River Formationcontains about 3 trillionbarrels of oil, and abouthalf of this may berecoverable, depending onavailable technology andeconomic conditions. TheRand Corporation, anonprofit researchorganization, estimatesthat 30 to 60 percent ofthe oil shale in the GreenRiver Formation can berecovered.
Socioeconomic benefits.Development of oil shaleresources could also yieldimportant socioeconomicbenefits, including thecreation of jobs, increasesin wealth, and increases intax and royalty payments tofederal and stategovernments for oilproduced on their lands.
Governments in OPEC nationsand other major net oilexporters need to assessthe likely impact of shaleoil on global oil pricesand their own revenues,
budgets and economies. Theyneed to consider how bestto respond in terms ofpotentially limiting growthin oil production tocounteract the potentialprice effects of increasedproduction outside OPEC.Where feasible, they alsoneed to consider developingtheir own shale oilexploration and production.
Major downstreamoperations, such asrefineries andpetrochemical plants, whichrely on oil and oilproducts, need to considernew sources of supply andthe potential for lowerfeedstock prices, both ofwhich may influence theperformance of existingassets and investmentdecisions in new ones
Chalenge of Environment andSocioeconomic
There are some problem withdevelopment of oil-shaleextraction industries. These areimpacts on water, air, andwildlife. In addition to theseenvironmental problem there isalso socioeconomic problem needto be solved.
Water: Developing oil shaleand providing power for oilshale operations and otheractivities will requirelarge amounts of water andcould have significantimpacts on the quality andquantity of surface andgroundwater resources.
Current estimates of thequantities of water neededto support a future oilshale industry varysignificantly depending uponthe assumptions that aremade. However, as 2010report noted, while water islikely to be available forthe initial development ofan oil shale industry, theeventual size of theindustry may be limited bythe availability of waterand demands for water tomeet other needs of theregion
Air. Construction and miningactivities during thedevelopment of oil shaleresources can temporarilydegrade air quality in localareas. There can also belong-term regional increasesin air pollutants from oilshale processing and thegeneration of additionalelectricity to power oilshale developmentoperations. Pollutants, suchas dust, nitrogen oxides,and sulfur dioxide, cancontribute to the formationof regional haze that canaffect adjacent wildernessareas, national parks, andnational monuments, whichcan have very strict airquality standards.
Wildlife: Oil shaleoperations are likely toclear large surface areas oftopsoil and vegetation, andas a result, some wildlifehabitat will be lost.Important species likely tobe negatively impacted from
loss of wildlife habitat. Inaddition, the withdrawal oflarge quantities of surfacewater for oil shaleoperations could negativelyimpact aquatic lifedownstream of the oil shaledevelopment.
Socioeconomic: Large-scaleoil shale development offerscertain socioeconomicbenefits, but it also posessome socioeconomicchallenges. Oil shaledevelopment can bring asizeable influx of workers,who along with theirfamilies, create additionalstress on localinfrastructure such asroads, housing, municipalwater systems, and schools.Development from expansionof extractive industries,such as oil shale or oil andgas, has typically followeda “boom and bust” cycle,making planning for growthdifficult for localgovernments.
CONCLUSION
At a global level, shale oil hasthe potential to reshape theglobal economy especiallyIndonesia where shale is verycommon rocks formation,increasing energy production,independence and affordability inthe long period. However, thesebenefits need to be squared withbroader environmental objectivesat both the local and globallevel. Consequent changes inpolicy and regulatory will haveimportant effects on oil
producers and consumers. Theeffects of a lower oil priceresonate along the entire energyvalue chain, and investmentchoices based on long-termpredictions of a steady increasein real oil prices may need to bereassessed. The potentialmagnitude of the impact of shaleoil makes it a profound force forchange in energy markets and thewider global economy. It istherefore critical for companiesand policy-makers to consider thestrategic implications of thesechanges now. Oil-shale extraction is 3 stepextraction with pyrolysis,hydrogenation, and thermaldissolution process. The producedoil can be used to generateenergies, thus can be used as asubtituents for conventional oil.Depending on availabletechnologies, this method can beimplemented to meet futureenergies needs in Indonesia.
ACKNOWLEDGEMENTS
The author would like to thank toall of student from GeologicalEngineering of DiponegoroUniversity especially 2012 friendwho always support and help himin writing this paper.
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Figure 1. Oil-shale Extraction invented by H.W Parker from PhillipsPetroleum Company. This process is in-situ process
Figure 2. Shale-oil Extraction using heated miscible fluids invented byM.Prats. This process is in-situ process
Figure 3. Shell in-situ converting process using wall conduction
Figure 4. Alberta Taciuk Combustion shaft used in internal combustion ex-situ process