Design through interpretation of a very large 3D VSP in a complex area in Jonah Field, Wyoming

Abstract

In the spring of 2005, EnCana Oil & Gas (USA) proposed the acquisition of a 3D VSP data set in a well later drilled in a complex compartmentalized portion of the Jonah gas field in Wyoming. Development of this area would benefit from the greater reliability of structural and stratigraphic interpretation enabled by the increased resolution of this 3D VSP. Figure 1 illustrates the acquisition geometry. Seismic data are recorded by downhole geophones at the center of ap-proximately 1400 source points. Surface source point signals are collected by a receiver array in the borehole. The resulting 6.5 mile2 survey was designed, permitted and acquired within a nine-month period in 2005. Innovative design and acquisition techniques led to successful acquisition on time and within budget.