An Integrated 3D-Seismic Exploration Method for Fractured Reservoirs in Tight Gas Sands

摘要

The three productive Unit Wells (28, 55 and 31) and the new prospect Wells (28E, 31E, 52, and 53) completed in 2004, appear to be predicted with nearly 100 percent success using the following methodology to explore for Lower Dakota gas:rn1. Lower Dakota Clay content less than or equal to roughly 13 percent,rn2. Phase Gradient (AVO) attribute indicating a phase difference between -15 to -85 degrees (gas saturation about 37 to 62 percent),rn3. Spot well near intersecting or swarming seismic lineaments, andrn4. Look for up hole fracture potential using Upper Dakota interval velocity anisotropy.rnWe interpret that natural fractures indicated by seismic lineaments have enhanced gas production. The drilling of the four prospect wells and the economic discovery of gas in three prospects (Wells 28E, 31E, and 52) and the predicted result of the poor producing prospect (Well 53) validates the results of our U. S. Department of Energy study. These outstanding drilling results confirm the value of GeoSpectrum's applied methodology in detecting commercial and prospective targets in fractured tight gas sands. Future work should include the development of an automated approach to map seismic lineaments and to apply the technology.