Petroleum geologist

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A petroleum geologist is an occupation that involves all aspects of oil discovery and production. Petroleum geologists are usually linked to the actual discovery of oil and the identification of possible oil deposits or leads. It can be a very labor intensive task involving several different fields of science and elaborate machinery.
Petroleum geologists look at the structural and sedimentary aspects of the strata to identify possible oil traps. Petroleum geologists make the decision on where the location of drilling will occur. This is done by locating a sedimentary basin. Petroleum geologists determine the well’s integrity with seven main aspects:

  • Source- The presence of Hydrocarbons in the reservoir.
  • Reservoir- The porous medium that contains the Hydrocarbons.
  • Seal- The rock unit that inhibits the oil from escaping the seal.
  • Trap- Structural feature that impedes the escape of Hydrocarbons.
  • Timing- The idea that events occurred in a certain order to allow the decomposition of organic matter into Hydrocarbons.
  • Maturation- The alloted time for the decompostition of organics into oil.
  • Migration- The flow of the (less dense) oil up the reservoir to the trap.


These seven key aspects allow the Petroleum geologist to obtain a 1-dimensional idea of the subsurface.
Some other data may be obtained via Geophysical methods. Geophysical logs show the seismology data of elastic waves. This allows a 3-dimensional look of the trap, and source rock. More data may be obtained from the mudlogger, who analyzes the drill cuttings and the rock formation thicknesses. [1] [2]