TY  - EJOU
AU  - Yang, Yuanyuan 
AU  - Shi, Xian 
AU  - Ji, Cheng 
AU  - Yan, Yujie 
AU  - An, Na 
AU  - Zhang, Teng 

TI  - The Hydraulic Fracturing Optimization for Stacked Tight Gas Reservoirs Using Multilayers and Multiwells Fracturing Strategies
T2  - Energy Engineering

PY  - 2024
VL  - 121
IS  - 12
SN  - 1546-0118

AB  - Based on a geology-engineering sweet spot evaluation, the high-quality reservoir zones and horizontal well landing points were determined. Subsequently, fracture propagation and production were simulated with a multilayer fracturing scenario. The optimal hydraulic fracturing strategy for the multilayer fracturing network was determined by introducing a vertical asymmetry factor. This strategy aimed to minimize stress shadowing effects in the vertical direction while maximizing the stimulated reservoir volume (SRV). The study found that the small vertical layer spacing of high-quality reservoirs and the presence of stress-masking layers (with a stress difference of approximately 3~8 MPa) indicate that interlayer stress interference from multilayers and multiwells fracturing between neighboring developed formations could affect the longitudinal propagation of the reservoirs. In addition, this study investigated well spacing optimization by comparing uniformly spaced wells (100–300 m) with asymmetric spaced wells (200 m upper layer, 250 m lower layer). Numerical results indicated that asymmetric spaced well placement yielded the largest stimulated reservoir volume (SRV) of 73,082 m<sup>3</sup>, representing a 65.42% increase compared to 100 m spaced wells. Furthermore, four different hydraulic fracturing sequences (interlayer, up-down, down-up, and center-edge) were compared for multilayer and multiwell networks. The center-edge sequence exhibited the lowest vertical asymmetry factor (0.71) and the least stress shadowing effects compared to the other sequences (0.78 for interlayer, 0.75 for up-down, and 0.76 for down-up). This sequence also achieved the largest SRV (486,194 m<sup>3</sup>), representing an 11.87% increase compared to the down-up sequence. Therefore, the center-edge fracturing sequence is recommended for multilayer development in this block. These results offer valuable insights for optimizing well placement and fracturing sequence design in multilayer well networks, ultimately advancing the development of multilayer fracturing technology in the region.
KW  - Multilayers and multiwells network; interlayer stress interference; hydraulic fracturing sequence; numerical simulation

DO  - 10.32604/ee.2024.056266