Surface-to-borehole TEM for reservoir monitoring

Abstract

The increasing need for continuous reservoir monitoring is one of the primary concerns to the oil industry to improve the hydrocarbon recovery factor and production efficiency. Several monitoring scenarios with geophysical methods can be derived including surface and borehole-based methods and their combinations. One is a surface electric current dipole and a vertical electric borehole receiver which has the strongest coupling in detecting the water flood front changes and is easy to implement. The surface-to-borehole electromagnetic if combined with seismic can give excellent resolving capabilities. A modeling study was performed to generate several results based on the given model. This is to support feasibility studies as well as to determine survey acquisition parameters. A 3-layer model was used with a hydrocarbon reservoir in the second layer. The optimum transmitter offset was determined by the modeling result and the value was used for the rest of the experiment. The resistivity of the hydrocarbon reservoir was also varied to observe the received vertical electric field. A time lapse study is relevant for the reservoir monitoring. We built and simulated 3-D model to apply this technology to real reservoirs. In combinations with reservoir simulator results it predicts the outcome of potential surveys. The model is then translated to time lapse fluid changes in order to design the survey layout such that we can get a maximum response. © 2011 Society of Exploration Geophysicists.