CONVEX HULL METHOD FOR SRV ESTIMATION

The prevalent use of induced hydraulic fracturing, commonly known as fracking, in reservoirs for shale gas demands that changes in geophysical properties within the fractured rock be studied. Hydraulic fracturing events typically take place over several hours. During this time, the seismic anisotropy of the reservoir rapidly changes. These dynamic seismic velocities can be modeled from reservoir attributes and properties that change during the fracking process. One such dynamic property is the stimulated reservoir volume (SRV) which has been investigated using the Cube and Surfer methods (Adejuyigbe, 2013). For this thesis, we present a new method for modeling the SRV based on minimum convex hulls. This method was implemented and tested using data from the Dollie Thorell Well in the Barnett shale in North Texas. Results from those tests show that the convex hull method is robust at modeling scattered microseismic event sets of spherical or cylindrical character. For these microseismic event sets, this modeling technique yielded a logarithmic increase in stimulated reservoir volume over time. The minimum convex hull method was implemented as a module within a 4D software framework to allow for the uniform data representation, processing flow, and visualization of future research methods. This work provides a starting point for SRV estimation research by investigating the minimum convex hull method while delivering effective 4D tools for future SRV estimation studies.