Single well seismic imaging of a gas-filled hydrofracture

摘要

A single well seismic survey was conducted at the Lost Hills, Ca oil field in a monitoring well as part of a CO2 injection test. The source was a piezoelectric seismic source and the sensors were a string of hydrophones hanging below the source. The survey was processed using standard CMP reflection seismology techniques. A potential reflection event was observed and interpreted as being caused by a near vertical hydrofracture. The radial distance between the survey well and the hydrofracture is estimated from Kirchoff migration using a velocity model derived from cross well seismic tomography. The hydrofracture location imaged after migration agrees with the location of an existing hydrofracture.