开江–梁平地区吴家坪组页岩气储层分布特征与有利区评价体系构建

Distribution Characteristics of Shale Gas Reservoirs and Construction of a Favorable Area Evaluation System for the Wujiaping Formation in the Kaijiang-Liangping Area

摘要: 开江–梁平地区上二叠统吴家坪组页岩具有良好的页岩气勘探前景，但储层非均质性强、甜点分布规律不清，缺乏针对性的有利区评价体系。本研究基于单井的测试数据及示踪剂产气占比资料，系统分析了影响吴家坪组页岩储层品质的主控因素，建立了有利区评价参数体系与分级标准。结果表明：单井尺度上含气量与产能相关性最高(R² = 0.18)，单簇尺度上TOC相关性最高(R² = 0.36)，不同尺度主控因素存在差异；采用灰色关联度法计算得到TOC、孔隙度、含气量和脆性指数的综合权重分别为0.30、0.23、0.29和0.18，其中TOC与含气量是关键控制参数。基于综合品质指数(X)建立了I~III类储层分级标准。井震结合预测揭示优质储层沿开江–梁平海槽呈条带状分布，南雅、巫山坎、五百梯等地区一类储层厚度较大。综合考虑储层厚度、埋深及构造条件，划分出南雅向斜、檀木场向斜、五百梯向斜等I类有利区。该评价体系为吴家坪组页岩气甜点预测及钻井压裂部署提供了科学依据，对类似层系页岩气评价也具有参考价值。

Abstract: The Upper Permian Wujiaping Formation shale in the Kaijiang-Liangping area exhibits considerable shale gas exploration potential; however, strong reservoir heterogeneity, unclear sweet spot distribution patterns, and the lack of a targeted favorable area evaluation system remain major challenges. Based on single-well test data and tracer-derived gas production proportion data, this study systematically analyzed the dominant factors controlling the reservoir quality of the Wujiaping Formation shale and established an evaluation parameter system with corresponding classification criteria. Results indicate that gas content exhibits the highest correlation with productivity at the single-well scale (R² = 0.18), whereas TOC shows the highest correlation at the single-cluster scale (R² = 0.36), revealing scale-dependent variations in the dominant controlling factors. Using the grey relational analysis method, the integrated weights of TOC, porosity, gas content, and brittleness index were determined as 0.30, 0.23, 0.29, and 0.18, respectively, with TOC and gas content being the key controlling parameters. A I~III class reservoir classification standard was established based on the comprehensive quality index (X). Integration of well logging and seismic data reveals that high-quality reservoirs are distributed in a belt-like pattern along the Kaijiang-Liangping trough, with greater Class I reservoir thicknesses in the Nanya, Wushankan, and Wubaiti areas. Considering reservoir thickness, burial depth, and structural conditions, the Nanya Syncline, Tanmuchang Syncline, and Wubaiti Syncline were classified as Class I favorable areas. The proposed evaluation system provides a scientific basis for sweet spot prediction and drilling/fracturing deployment in the Wujiaping Formation shale, and offers reference value for shale gas evaluation in analogous strata.