WANG Hanqing, CHEN Junbin, ZHANG Jie, XIE Qing, WEI Bo, ZHAO Yiran. A New Method of Fracability Evaluation of Shale Gas Reservoir Based on Weight Allocation[J]. Petroleum Drilling Techniques, 2016, 44(3): 88-94. DOI: 10.11911/syztjs.201603016
Citation: WANG Hanqing, CHEN Junbin, ZHANG Jie, XIE Qing, WEI Bo, ZHAO Yiran. A New Method of Fracability Evaluation of Shale Gas Reservoir Based on Weight Allocation[J]. Petroleum Drilling Techniques, 2016, 44(3): 88-94. DOI: 10.11911/syztjs.201603016

A New Method of Fracability Evaluation of Shale Gas Reservoir Based on Weight Allocation

  • Existing shale gas reservoir fracability evaluation methods cannot be used in continuous fracability evaluation of reservoirs. After a quantitative evaluation of the parameters of geological sweet spots and the calculation of engineering parameters by combining the contents of mineral composition and the micromechanics parameters, a new shale gas reservoir fracability evaluation model based on weight allocation through standardization, normalization, harmonic averaging and arithmetic averaging methods was developed. This model considers the gas-bearing potential and stimulation potential of shale gas reservoirs, with four critical parameters (total organic carbon (TOC), vitrinite reflectance (Ro), shear modulus, and fracture toughness) defined for fracability evaluation which takes into consideration both geological and engineering criteria for sweet spots. It is proposed that shale gas reservoirs with TOC 2%, Ro 1.3%, silica mineral content of 20%-60%, carbonate mineral content of 10%-30%, and clay mineral content of 30%-50%, are good candidates for hydraulic fracturing. This model was used to evaluate the fracability of reservoir sections in Well W, a shale gas well in the Weiyuan area of the Sichuan Basin. Microseismic monitoring results showed that multiple fractures were generated during fracturing. This indicated that this model could be used in continuous fracability evaluation of shale reservoirs. From the calculated results, the pay zone and barriers could be identified accurately. So the proposed model is highly operable and worthy of engineering applications.
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