Acquisition Services - Massive 3D VSP®

Paulsson Geophysical Services, Inc. (P/GSI) is recording Massive 3D VSP's® using it's proprietary 80 to 400 level borehole seismic receiver arrays. The seismic data recorded is generated using surface seismic sources such as surface seismic vibrators, dynamite or marine airguns. The length of P/GSI's patented 80 to 400 level clamped three component borehole seismic receiver array depends on the number of receivers deployed and the spacing between each receiver. The receiver pod spacing can be as short as 4 ft or as long as 100 ft. The 80 level arrays with a geophone pod spacing of 50 feet are 4,000 ft long. The 160 level arrays with a receiver spacing of 50 ft, as used in a 2003 Texas survey, are 8,000 ft long. By using all 400 levels spaced 50 ft apart the longest array that can be deployed using the P/GSI system is 20,000 ft.

Paulsson Geophysical Services, Inc. (P/GSI) has recorded a number of Massive 3D VSP® surveys with it's 80 to 400 level 3C clamped borehole seismic receiver array. Recent examples include a 1.5 million trace, 3 well Massive 3D VSP® in Oman, an 800,000 trace single well Massive 3D VSP® using a 160 level array in Texas, a 3 million trace 4 well Massive 3D VSP on the North Slope Alaska, a 7.5 million trace 5 well offshore Massive 3D VSP offshore California, a 1 million trace, 8 well Massive 3D VSP® recorded near Bakersfield in California, a 350,000 trace single well 3D VSP recorded in Alberta, Canada.

In the surveys mentioned above much smaller scale reservoir features, including faults and pinch outs, were mapped than what has been possible using surface seismic methods. Using the recorded bandwidth of 10 - 200 Hz in the 3D VSP a resolution of better than 5 m (15 ft) was evident in the final images from one of the surveys.

The most cost effective application of the P/GSI downhole seismic arrays is where surface seismic technology fail to produce images that can be used for drilling decisions.