Hydraulic fracture quality from time lapse VSP and microseismic data
Author:
Willis, Mark E.; Willis, Kent M.; Burns, Daniel R.; House, N.J.; Shemeta, J.
Abstract:
The ability to produce from low permeability, tight gas reservoirs is directly tied to the
ability to repetitively perform successful hydraulic fracturing in a series of closely spaced
wells. The key question is whether the induced fractures remain open and permeable, which is
in part a function of the stress field and the emplacement of proppant. We study the ability to
detect and characterize hydraulic fractures from scattered seismic energy. A 3D VSP forms
the reference for seismic reflectivity before hydraulic fracturing. During the hydraulic
fracturing the microseismic events are recorded and then the arrival times picked and the
events located. Another 3D VSP survey is recorded after the fracture treatment. The
difference between the VSP surveys yields a 3D time lapse VSP dataset which contains the
changes in the reflected wave field and the addition of scattered energy. The microseismic
moveout times can be used to extract from the time lapse VSP data the seismic energy
scattered from the induced fracture planes. We show the encouraging results from both
model and field data.