Integrated Workflow Using 3D Seismic and Geomechanical Properties with Microseismic and Stimulation Data to Optimize Completion Methodologies: Wolfcamp Shale-Oil Play Case Study in the Midland Basin
Authors: Zakhour Nancy , Shoemaker Michael , Lee Don 
Published: October 2015

This study presents the results of an empirical modeling approach using integrated multidisciplinary measurements to optimize completion methodologies and future field development for stacked laterals. The objective is to ultimately high-grade basin-wide exploratory Wolfcamp landing zones from 3D seismic data. Shale mineralogy compositions and geomechanical properties are directly measured from 3D surface seismic data along lateral well trajectories at individual hydraulically stimulated stages which are monitored real-time using microseismic acquisition. Extrapolated lateral synthetic logs from 3D seismic of said shale properties, combined with microseismic and completions data, are numerically modeled to simulate hydraulic fractures for optimal completions design. Successful implementation is critical in landing areas with complex depositional environments characteristic of laterally varying mineralogy compositions and rock mechanics.

The method is tested in the prolific oil-bearing Wolfcamp shale-oil play of the Midland Basin, West Texas, on three laterals drilled in a "chevron pattern", two of which in the deeper Wolfcamp B formation and the third in the Wolfcamp A. Real-time microseismic monitoring is used to measure the spatial and temporal evolution of the stimulation. Although identical pumping schedules are initially intended for all three laterals stimulated in a "zipper sequence", with geometric stage placement, it becomes apparent that mapped microseismic height varied significantly across the given laterals at individual stages with no apparent relationship with treatment injection rates.

However, post-frac analyses of the microseismic and petrophysical data shows strong correlations between fracture height variability with: 1) lateral changes in shale facies and subsequent mineralogy composition, and 2) P-wave and S-wave log impedances which are ultimately tied to the 3D surface seismic data. Optimal fracture heights are observed in landing areas with significant volume of calcite, regions of high Young's modulus and closure stress. Production history match of those laterals and several others in the field confirms a strong correlation between seismic P- and S-wave impedance and initial 120-day-cumulative oil in landing zones where high volume of calcite exists.

Further field development of stacked laterals requires optimal containment of fracture heights within pay zones, requiring an innovative integrated workflow. This involves the incorporation of 3D seismic with microseismic data which should be used to calibrate fracture modeling simulations for an optimized stimulation treatment schedule (i.e., volumes pumped with optimal slurry rates, etc.) Synthetic lateral logs from 3D seismic, representing estimated measurements of petrophysical and geomechanical rock properties can also be used to develop an engineered completion solution for cluster placement and stage spacing.