Completion design for unconventional shale plays in North America is a topic of high current interest. Although the practice of stimulating shale horizontal wells with large slickwater treatments is slowly changing to the use of Hybrid/Crosslink treatments in certain plays, little has changed with the method of completion design itself. Most laterals are completed using a ‘cookie cutter’ approach in which the number of stages and clusters, cluster spacing and other design parameters are based on statistics, past experience, rules of thumb or client shared knowledge, and are not tuned to the specific conditions in a particular well.
This paper presents a case study from the Eagle Ford Shale and describes a step-by-step workflow to simulate hydraulic fractures using a state of the art, reservoir-centric stimulation design tool (RCSD). The presented approach incorporated petrophysical data acquired in a vertical pilot hole with horizon interpretation, a discrete fracture network (DFN) model conditioned by seismic interpretation, image log data from a horizontal well, and completion data into a hydraulic fracture simulator. Simulation of fracture geometry was performed stage-by-stage in the RCSD tool using the recently developed unconventional fracture model (UFM), which is optimized specifically for complex fracture networks. The modeled fracture network was calibrated to microseismic events via fluid rheology and fluid loss variables while also accounting for a stress shadowing effect.
The output of the simulator includes a list of parameters such as fracture surface area, fracture propped surface area, and hydraulic fracture network geometry that can be used for the determination of estimated stimulated volume (ESV) as well as inputs into reservoir simulation for production history matching and forecasting. Also, this application of the RCSD tool in the Eagle Ford Shale provides an ability to test most aspects of the completion design by modeling stimulated volume change with respect to pumping schedule and completion parameters.