traps_masoom

Presentationon

Traps and its Classification

Presented To:Dr. Naveed Ahsan

Presented By:Masoom ShaniGhulam AkbarMaan Malik 4th Prof (2012-2016)Institute of Geology, University of the Punjab,Lahore.

Traps and its types

TABLE OF CONTENTSBasic TermsTraps & their Classification

Structural TrapsStratigraphic Traps

Combination TrapsTraps with reference to Pakistan

Conclusions

References

Basic Terms

• Porous Rock: Rock, which contains pores in it.• Permeable Rock: Rock, which contains

interconnected pores in it.• Source Rock: “Rock, which generate

hydrocarbons”.• Reservoir Rock: “Porous and permeable rock

unit, which holds hydrocarbons”.

Seal or Roof rock

• An impermeable rock that acts as a barrier to the passage of further upward migration of Hydrocarbons, migrating in the subsurface.

• Common seals are:– Shale– Evaporites

• Seal overlies the reservoir rock to form a trap or conduit.

• Also known as roof rock and cap rock

Pool

• An underground accumulation of petroleum or gas usually forming a reservoir in porous Sedimentary rock.

Field

• A pool is a subsurface deposit of oil and/or gas that occurs in a separate reservoir under a single pressure system. A field is a group of pools related to a single stratigraphic feature, structural feature, or geographic area.

Trap

• A trap is the place where oil and gas are barred from further movement….(Levorsen, 1967)

• Trap is one of the key element of a petroleum system, the others are;

Source RockReservoir RockSeal or Cap or Roof RockThermal MaturityMigration of Petroleum

Nomenclature of a Trap

• Crest or Culmination: Highest point in the trap

• Spill point:Lowest point of the trap up to which HC is contained

• Spill Plane:Horizontal contour cutting spill point

• Pay:The productive reservoir i.e. vertical interval of HC


• Closure:Vertical distance from crest to spill plane

• Bottom waterWater zone immediately beneath the

petroleum reservoir• Edge water:

Zone laterally adjacent to the reservoir

Classification of Traps

• Numerous classifications of traps has been proposed. Most commonly these are divided into 3 categories;

1) Structural Traps

2) Stratigraphic Traps

3) Combination Traps


Structural Traps• Tectonic – Extensional– Contractional

• Compactional– Drape structures

• Diapiric– Salt movement– Mud movement

Structural Traps(Extensional)

Structural Traps(Contractional)

Structural Traps(Compactional)

• Formation of drape anticline by differential compaction

Structural Traps(Diapiric)


Stratigraphic Traps• Depositonal– Reefs– Pinch outs– Channels– Bars

• Unconformity – Truncations– Onlap

• Diagenetic– Mineral

Stratigraphic Traps(Pinch outs)

Stratigraphic Traps

Traps Percentage

Examples w.r.t Pakistan

Basins of Pakistan

• There are two main basins of Pakistan:1. Indus Basin2. Baluchistan Basin• Others smaller basins are :i. Peshawar Basinii. Pishin or Kakar-Khorasan Basin

Basin Map of Pakistan

1.Upper Indus Basin

Potwar Sub- Basin

Kohat Sub-Basin

Lower Indus Basin

• On the basin of structure, lower Indus basin is divided into 3 segments:

• Kirther Fold Belt• Thar Platform • Offshore Indus

Gas fields of Thar Platform

cross-section through the center of the southern Indus basin

Baluchistan Basin

Production Profile from 1944-1991(Chorgali/ Sakesar)

References

• Petroleum Geology by I.B Kadri• Petroleum Geology by F.K North• Petroleum Geology by Levorsen• Petroleum Geology by R.C Selley• Manual of OGDCL • PAPG Annual Technical Proceeds• Wandery C.J., Law B.E., and Shah H.A., 2004, Patala -Nammal Composite Total

Petroleum System, Kohat-Potwar Geologic Province, Pakistan• Shami B.A., and Baig M.S., 2002, Geomodelling for the enhancement of

Hydrocarbon Potential of Joya Mair oil field, Potwar, Pakistan• Ahmad, S., Alam, Z., and Khan, A.R., 1996, Petroleum exploration and production

activities in Pakistan: Pakistan Petroleum Information Service, 72 p• Khan, M.A., Ahmed, R., Raza, H.A., and Kemal, A., 1986, Geology of petroleum in

Kohat-Potwar Depression, Pakistan: American Association of Petroleum Geologists Bulletin, v. 70, no. 4, p. 396–414

traps_masoom

Engineering