An Integrated 3-D Seismic Fracture Interpretation Methodology for Tight Gas Reservoirs

摘要

The interpretation method is based on a comprehensive reservoir characterization of the Lower Dakota sandstone in a gas-producing unit in Rio Arriba County, NM. The following reservoir attributes are used: 1. seismic lineament mapping predicts reservoir fractures in the reservoir section; 2. seismic interval velocity anisotropy investigates fractured reservoir potential in tight sands up-hole from the main reservoir target; 3. a collocated cokriged clay volume map for the Lower Dakota, along with additional geologic attributes, screen lead areas defined by regions of "swarming" multidirectional lineaments; and 4. a gas-sensitive amplitude variation with offset seismic attribute, near trace stacked phase minus far trace stacked phase, phase gradient, is used to further define drill locations having high gas saturation. A four-well drilling program recently was completed to test the fractured gas reservoir prospects and exploration technology. The nearly 100% success ratio of the drilling program indicates the fracture detection method is ready for commercial application.