Fracturing and production analysis of the efficacy of hydraulic fracture stage reduction in the improvement of cost‐effectiveness in shale oil development: A case study of Jimsar shale oil, China

• Published in: Energy science & engineering 2021-09, Vol.9 (9), p.1337-1348
• Main Authors: Zhi, Dongming, Guo, Xuyang, Wang, Wei, Jin, Yan, Liu, Caiguang, Chen, Gang, Wang, Zhenlin
• Format: Article
• Language: English
• Subjects: Clusters; Comparative studies; Cost analysis; Costs; Crack propagation; Fracture mechanics; Geomechanics; Horizontal wells; Hydraulic fracturing; Methods; Modelling; multistage fracturing; Numerical analysis; numerical simulation; Oil and gas industry; Oil field equipment; Oil shale; Plugs; production prediction; Propagation; Reservoirs; Rock mechanics; Shale oil; Shales; Stimulation; Stress measurement; Tensile strength; Uncertainty; Volatility
• ISSN: 2050-0505; 2050-0505
• DOI: 10.1002/ese3.940

The effective production of shale oil is important for the cost‐effectiveness in the oil and gas industry. Oil price volatility and uncertainty require suitable hydraulic fracturing schemes to maximize production and to minimize fracturing costs. Since the reduction of fracture stage saves bridge plugs and fracturing costs, it is considered as a possible method to improve the cost‐effectiveness. To maintain the stimulated reservoir volume, cluster numbers per stage are consequently increased, which may induce nonuniform fracture propagation and interference which affects the stimulation efficiency. This study conducts a comparative study for single‐stage (reduced) and two‐stage (not reduced) fracturing schemes with the same fracturing fluid volume. Reservoir geomechanics and rock mechanics analyses are conducted for Jimsar shale oil in north‐western China with a single‐stage multicluster fracturing model established. Fracture geometries and key factors are investigated followed by the evaluation of the fractured well production. The relationship between multicluster parameters and production is quantified. Meanwhile, two‐stage fracturing modeling is also set up to compare with single‐stage fracturing modeling. Fracturing results show that although single‐stage fracturing results in nonuniform fracture propagation, the overall stimulation is satisfactory. Production results show that the nonuniform growth of fracture clusters leads to different contributions to the production from individual clusters and the production from inner fractures is significantly inhibited. Compared with two‐stage fracturing with the same pumping volume, it is found out that single‐stage fracturing can lead to cost‐effective horizontal well production in Jimsar shale oil given certain values of hydraulic fracturing costs, and the reduced stage scheme is preferable in low oil price and high uncertainty scenarios. The use of hydraulic fracture stage reduction can mitigate fracturing interferences and lead to more uniform hydraulic fracture growths. Consequently, more uniform productions from individual fractures can be obtained, indicating more uniformed depleted SRVs.