Geology in the Oil and Gas Industry - Essay Example

1. What caused the Himalayas? – The movement of the Indian subcontinent and its impact on the Asian continent formed the Himalayas, through a slow process of head-on collision or crustal collision (Van Dyke 4).
2. Draw an anticline and a syncline.

Figure 1. Folding of the earth’s crust leads to upwarps called anticlines, and downwarps called synclines (Van Dyke 5).

6. Why are anticlines important? – Anticlines are important to petroleum geologists because these structures more often than not contain petroleum deposits (Van Dyke 6).
7. Where is oil often found in the North Sea? – Oil in the North Sea is often found in sediment graben, which is a hollow block of crust that sunk between two faults (Van Dyke 8).
8. Name two kinds of igneous rocks. – Two kinds of igneous rocks: granite (course-grained volcanic rock); basalt (fine-grained volcanic rock) (Stille, Fichter, and Young 6).
9. Name two sedimentary rocks. – Two sedimentary rocks: limestone; clay (Van Dyke 11).
10. Which type of rock is most likely to contain petroleum? – Sedimentary rocks are mostly found near coastal lines due to mineral deposition through time. Thus sedimentary rocks most likely contain petroleum, as exemplified by large oil deposits along seacoasts like the Persian Gulf (Van Dyke 12).
11. Explain the inorganic origin of oil, which origin do you think is most likely, organic or inorganic? – The inorganic theory of the origin of oil states that oil deposits were formed during the creation of the planets or the formation of the solar system (Van Dyke 14). This theory explains why petroleum from a large deposit is similar even though the rocks where they were found were different in structure. However, petroleum is made up of hydrocarbons, which come from the decomposition of living things (Van Dyke 13). Thus the organic theory is much more plausible than the inorganic theory of oil formation.
12. Which has more permeability, a box of popcorn or a similar box of sand? – An object is said to be permeable if its pores are interconnected, and water can flow through it through these pores (Van Dyke 15). Therefore, a box of sand has more permeability than a box of popcorn, mainly because the sand has more interconnecting pores than the popcorn.
13. What is shale oil rock known for? – Shale oil rocks are known to be porous but not permeable, thus making oil hard to get through conventional methods (Van Dyke 15).
14. What is tar sand hydrocarbon? – Tar sand hydrocarbons are sticky types of oil deposits, cemented together by tar or asphalt (Van Dyke 15).
15. Name and define three types of traps. – Three types of traps are structural traps, formed during folding or faulting of rocks (e.g. anticlinal traps); stratigraphic traps, formed by a nonporous formation that sealed off the top edge of a reservoir bed or through a change in the porosity/permeability of the reservoir bed (e.g. lenticular trap); combination traps, formed by the combination of folding or faulting of rock and the change in permeability of the reservoir rock (Van Dyke 20).
16. What fluids are commonly found in a reservoir rock? – Fluids mostly found in reservoir rock are water (since most sedimentary rocks form near or in the sea); oil; and natural gas (Van Dyke 21).
17. Explain the difference between normal pressure and abnormal pressure. – Normal pressure of reservoir fluids usually occurs when the reservoir has an outlet to the surface, and the only pressure inside the reservoir is only due to the downward exertion of the fluids (Van Dyke 23). Abnormal pressure is when the pressure in the reservoir is caused by the combination of the impermeable rock formations surrounding the reservoir and the pressing down of these rock formations onto the reservoir, and no outlet to the surface causes fluid pressure buildup in the rock itself (Van Dyke 24).