FIELD DATA

Arco acquired approximately 4 square miles of 3-D one-component data over a fractured reservoir in the Powder River Basin in Wyoming. The object of the project was to demonstrate that fracture orientation and density can be determined from compressional wave surface seismic surveys in a cost effective manner. The quality of the data is very high, as Figure 3 shows. The cube is a DMO-stack of the 3-D survey, which illustrates the structural image of the data. The dominant geology of the area is flat. The objective target, the Niobrara/Frontier horizon, is about 10,500 ft deep (approximately 2.2 seconds). The top slice of the cube shows the top of the formation of interest. The stacked reflectivity at that depth does not display any major structures.

Previous 2D work in the area showed evidence of anisotropy through shear wave splitting, P-wave velocity analysis, reflectivity studies, and AVO inversion. The data offers itself as a good candidate for testing our techniques for ``true-amplitude'' processing of wide-azimuth surveys.

 

data-cube
Figure 3 DMO stack of the 3-D survey.