Optimization of Hydraulic Fracturing Design in Unconventional Formations: Impact of Treatment Parameters

Abstract

Due to technical and economical limitations of hydrofracturing operations in unconventional reservoirs worldwide, an optimized hydraulic fracturing design is critical to achieve a successful well stimulation operation. The number and length of perforation clusters in each stage, proppant and fluid frac compatibilities, and optimum spacing, are some of the challenges inhibiting successful hydraulic fracturing operations across the world. In this study, we aim to investigate the effects of varying fracture-cluster lengths, proppant types and sizes, and frac fluid types, on hydraulic fracturing treatments using 2D and 3D simulation models. Our study relies on petrophysical log data, geologic data, well data, reservoir data, and production data from a well in the Eagle Ford shale formation. Firstly, we created stress log and developed a stress profile to determine fracture initiation location and orientation. We selected different combinations of frac-fluids and proppant types, 5 fracture-cluster lengths in a single stage, 2 different spacing lengths between fracture clusters, determined the maximum allowable treatment pressure, and selected an ideal fracture propagation model. Secondly, we selected an optimum treatment size, followed by performing the production forecast and the net present value analyses. In the third task, we determine the optimal specifications of the fracturing fluid and proppant, fluid volume and proppant weight, followed by creating a schedule for fluid injection and proppant mixing, and injection pressure profile prediction. Our results show that greater cluster lengths provide better and optimized hydraulic fracture treatment in some cases because of greater proppant coverage, fracture conductivity, stimulated reservoir volume (SRV), fracture half-length, and propped length. In the results obtained from varying proppant sizes and frac fluids in cases 2 and 3, we observed that Northern White 30-50 proppant produced a lower fracture conductivity (average of 2.0 md-ft) and fracture half-length (91 to 123 ft), in comparison with proppant composed of Badger 100 mesh and RC Sand PC 16-30, which achieved a greater fracture conductivity (> 3.0 md-ft) and fracture half-length (129 to 148 ft). In the 3 cases we investigated, we observed that stress shadowing and interference hindered the growing fractures which eventually led to a collapse of some fractures. We believe that our preliminary study will provide valuable critical decision-making during hydraulic fracturing operations in various unconventional formations across the world.

Comparative evaluation of multi-basin production performance and application of spatio-temporal models for unconventional oil and gas production prediction

“…Hence, if the goal of the study is capturing the mean, then select the GAM model, otherwise, the FRK model is better suited for the analysis. The importance of drilling and completion technology, and geological consideration to the successful development of unconventional resources is well documented (Chong et al 2010;Kolawole et al 2019 Pope, et al 2010;Sharma et al 2014;Soliman, et al 2014). For this reason, completion and geologic parameters were included in the Bakken models because these variables were available.…”

Evaluation of geomechanical properties via scratch tests: Where are we and where do we go from here?

“…In the optimization of hydrocarbon exploitation, hydraulic fracturing has proven to be one of the most efficient matrix stimulation methods in unconventional reservoirs [3,4]. During this treatment, complex fracture networks are often generated, and the interaction of hydraulic and natural fractures significantly influences the complexity of the fracture networks created [5,6].…”

How will treatment parameters impact the optimization of hydraulic fracturing process in unconventional reservoirs?

“…A portion of our results included in this study was first presented in Kolawole et al [16] and Wigwe et al [17]. In this study, we designed optimal hydraulic fracturing treatment, followed by investigating how proper selection and application of fracture treatment parameters influence hydraulic fracturing process by varying fracture cluster lengths, fracturing fluid types and viscosities, proppant types and densities, and fluid pump injection rates; utilizing data from 2 unconventional horizontal gas wells.…”