Optimization of hydraulic fracturing with rod-shaped proppants for improved recovery in tight gas reservoirs

Abstract

Due to the increasing demand and importance of natural gas in the global energy mix, its expeditious recovery is crucial, especially from large-scale unconventional geo-resources. Hydraulic stimulation is an established means of productivity increase especially from tight gas reservoirs. The fracture conductivity generally depends on proppant properties, particularly the shape. Therefore, in this research, the effect of using rod-shaped proppants was investigated. Using rod-shaped proppants instead of conventional spherically shaped proppants, can make a significant difference. Due to the cylindrical shape, higher porosity and permeability are generated, resulting in better conductivity fractures. Thus, to analyze the effect of different proppant shapes on post-fracture performance, a production model was implemented in the FLAC3Dplus-TMVOC framework. Later, an in-depth sensitivity analysis was performed to investigate the effects of the proppant shape, size, strength, and effective stress on the fracture aperture reduction and conductivity due to proppant deformation and embedment. The application to a generic model revealed that recovery can be increased by about 7% using aspect ratio 1 rod-shaped proppant with the same diameter as the spherical proppant. Then, increasing the rod-shaped proppant size from an aspect ratio of 1–10 can significantly increase the gas recovery by 13% but results in higher proppant deformation. Finally, the application of rod-shaped proppants to fracturing proposals in well x in a tight gas reservoir of Germany showed that the recovery could be significantly improved if spherical proppants are replaced with rod-shaped proppants.