The Geological Scheme
A major role for the production geologist is to establish the geological scheme for the field. This is the conceptual scheme, which depicts the sedimentological and structural configuration of the reservoir. Once a geological scheme is in place, it can be integrated with production data to produce a flow geology scheme. This is a description of how the various geological elements in the reservoir control the patterns of fluid flow. The conceptual geological scheme for the larger fields will be represented as a geological model on a computer to be used by the geologist and the rest of the subsurface team. A computer representation can be built either as a series of 2-D maps or as a 3-D geological model (Figure 39).
The geologist will use these models to locate and target the remaining hydrocarbons within a field. Any large 10 pockets of oil identified in this way will be the basis for infill well drilling. The geological model can also be used to provide the framework for the reservoir engineer’s simulation model. The reservoir simulation tracks fluid flow within the reservoir and is the basis for predicting future production and reserves.
The workflow given here follows through from establishing a geological scheme to building a geological
Figures & Tables
Oil Field Production Geology
This book was written for students, new professionals in oil companies, and for anyone with an interest in reservoir geology. It explains the background to production geology in the context of oil field subsurface operations. It also gives practical guidelines as to how a production geologist can analyze the reservoir geology and fluid flow characteristics of an oil field with the aim of improving hydrocarbon recovery. Advice is given on how to search for the remaining oil volumes in a producing field, where these pockets are typically found, and then how to plan wells to target these volumes.