Temperature, Pressure and Fluid Flow Modelling in Block 330, South Eugene Island Using 2D and 3D Finite Element Algorithms
Dimas F.S. Coelho, Alex Erendi, and Lawrence M. Cathles
The area centered around South Eugene Island (SEI) Block 330 consists of thin sands interlayered in shale cut by a complex network of faults bordering a salt withdrawal minibasin. The main ("Red") fault is believed to be the feeder fault for the giant Block 330 oil field.
A new 3D seismic interpretation tied to well logs and petrophysical data was used to construct 9 consistent (same number of strata and pseudowells) SW-NE cross sections depicting the geometry of the minibasin along with faults and salt. The basin evolution is modeled using a 3D Finite Element program. The kinetic model evolution accurately simulates movements across 5 representative faults and gives a reasonable history of the salt movement from 3.4 million years, when the now buried salt sill was at the sea floor. Allen-plane maps showing sand-sand connections over time can be obtained taking compaction into account. The kinetic model predicts porosity variation with time.
Temperatures were calculated taking account of the dependence of thermal conductivity on porosity, temperature and hydrocarbon saturations. The insulating effect of the Block 330 oil and gas reservoirs produces a significant positive anomaly below the reservoirs and negative above that are similar in form to those observed from bottom-hole temperature measurements.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California