Which of the following hydrocarbon trap(s) is/are a result of sedimentary facies changes?
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- Salt dome
- Unconformity
- Pinch out
- Sand lens
The Correct Option is B
Solution and Explanation
- Salt dome is a structural trap caused by diapirism of salt, not by facies change.
- Unconformity traps occur where erosion or non-deposition truncates reservoir units, followed by sealing. This is a stratigraphic effect.
- Pinch out traps form when a porous reservoir facies thins out and pinches against non-permeable facies. This is due to facies variation.
- Sand lens traps occur where isolated sand bodies are encased in shale due to depositional changes.
Hence, traps due to sedimentary facies changes are (B), (C), and (D).
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Identify the option that has the most appropriate sequence such that a coherent paragraph is formed:
Statement:
P. At once, without thinking much, people rushed towards the city in hordes with the sole aim of grabbing as much gold as they could.
Q. However, little did they realize about the impending hardships they would have to face on their way to the city: miles of mud, unfriendly forests, hungry beasts, and inimical local lords—all of which would reduce their chances of getting gold to almost zero.
R. All of them thought that easily they could lay their hands on gold and become wealthy overnight.
S. About a hundred years ago, the news that gold had been discovered in Kolar spread like wildfire and the whole State was in raptures.
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\[ \begin{aligned} N & = \text{Initial (original) oil in place, stb} \\ G & = \text{Initial volume of gas cap, scf} \\ m & = \text{Ratio of initial volume of gas cap to volume of oil initial in place, rb/rb} \\ S_{wi} & = \text{Initial water saturation} \\ S_{oi} & = \text{Initial oil saturation} \\ B_{oi} & = \text{Initial oil formation volume factor, rb/stb} \\ B_{gi} & = \text{Initial gas formation volume factor, rb/scf} \end{aligned} \]
The total pore volume (in rb) of the reservoir is:
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