An oil company geologist’s role can encompass a range of tasks and responsibilities depending on which particular department the geologist is placed within. These departments can broadly be split up into Exploration, Development, Operations and Wellsite.
An Exploration Geologist is broadly responsible for finding suitable areas to drill a well and discover new hydrocarbons. To do this, they integrate various (sub)regional subsurface data including various types of models, maps, seismic data and nearby well data. Using geologic concepts to integrate these data helps the Exploration Geologist identify areas where there may be a greater likelihood of encountering trapped hydrocarbons. More detailed geologic assessments of these smaller areas can help identify leads and prospects for drilling.
A Development Geologist is broadly responsible for understanding the reservoir geology of an oil or gas field. They usually work within a multi-disciplinary team who are all responsible for safely extracting the maximum amount of hydrocarbons from a field. A Development Geologist needs to integrate lots of different data in order to help understand the geology of the field. These data may include seismic, down-hole measurements acquired by petrophysical logging, whole and sidewall core analysis and numerous geologic-based post-well studies. They may also work with Reservoir Engineers to help build and/or update computer generated subsurface models to help understand the distribution of the reservoir and its fluids. These models can be used to predict the reservoir’s behavior as fluids are produced and can help identify areas to drill new wells.
An Operations Geologist is the main geologist in charge of drilling a well. They make key contributions in the planning of a well; are usually responsible for geological decisions made during the drilling of a well and help co-ordinate the geologic studies carried out once the well is completed. An Operations Geologist is usually based onshore and is a crucial link in the communication chain. They are involved in decisions during the drilling of the well which may include on and offshore Drilling Engineers, Wellsite Geologists and the Drill Site Manager.
A Wellsite Geologist is the geologist who is primarily responsible for overseeing all geological duties on a rig offshore. When a well is being drilled, the drill bit cuts the rock into small pieces as it drills further into the formation. Those rock pieces are called cuttings and are transported up the wellbore where they are collected at the surface. The main role of the the Wellsite geologist is to prepare and describe the cuttings, compile a log of their descriptions, identify stratigraphic boundaries and note any hydrocarbons within the samples. Usually they are also involved in overseeing coring and petrophysical logging procedures.
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