| Summary: | The purpose of this study is to investigate the effect of principal stress direction on the efficiency of hydraulic fracturing treatment. There are two different drilling scenarios: 1. Four horizontal wells drilled in four orthogonal directions regardless of in-situ stress condition (“Actual”). 2. Three horizontal wells drilled equivalent to “Actual” case by considering the direction of principal stress (“Proposed”). The hydraulic fracturing modeling was carried out based on well logging data and completion reports of Brushy Canyon formation, Permian Basin. In the results of “Actual” case, transverse fractures were generated in two horizontal wells drilled parallel to σ<sub>hmin</sub>-dir (direction of σ<sub>hmin</sub>), similar to “Proposed” case. Meanwhile, for two other wells drilled perpendicular to σ<sub>hmin</sub>-dir, longitudinal fractures were generated. These obliquely deviated fractures significantly decreased the fracture spacing between the stages up to 26%. This induced great stress shadow, however, the fractures propagated straight due to the large stress anisotropy of 2000 psi (σ<sub>Hmax</sub>/σ<sub>hmin </sub>= 1.4). Therefore, it was found that due to the different direction of fracture propagation in “Actual” case, “Proposed” case was 14.6% of stimulated reservoir volume (SRV) higher. In conclusion, for successful hydraulic fracturing treatment, the direction of horizontal well must be determined in consideration of the principal stress direction as well as stress anisotropy.
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