四川盆地南川区块页岩气开发潜力分析

Analysis of Shale Gas Development Potential in Nanchuan Block Sichuan Basin

摘要: 以四川盆地东南缘南川区块五峰组–龙马溪组一段页岩气藏为例，评价气藏立体开发潜力。基于工区岩心分析化验、测井、微地震监测和试采等数据资料，分析了气藏地质特征和储量动用情况，评价了单井产能。结果表明：目的层为深水–半深水陆棚沉积，岩性为黑色页岩，纵向厚度110 m左右，属低孔特低渗气藏，脆性矿物含量高，地应力适中，可压性好，纵向上可划分三套开发层系，储量规模达1700 × 10⁸ m³，具备较好的开发资源基础；194-X井区一套井网开发平均单井EUR为1.08亿方，仅动用下部厚度30~50 m，剩余气占比55.32%，三套井网开发资源动用更充分，采收率可达28.4%，平桥背斜南斜坡、东胜背斜和上部单井产能落实，预测页岩气产气量可达482.8 × 10⁸ m³。研究结果证实工区具有较高的立体开发潜力，对提高储量动用程度和扩大产建规模有一定的借鉴意义。

Abstract: Taking the shale gas reservoirs of Wufeng Formation-subsection of Longmaxi Formation in the Nanchuan Block in the southeastern margin of the Sichuan Basin as an example, the tridimensional development potential of the gas reservoir is evaluated. Based on the data of core analysis, logging, microseismic monitoring and production, the geological characteristics of gas reservoirs, reserves utilization are analyzed, and the single well productivity is evaluated. The results show that the shale gas reservoir of target Zone is a deep-semi-deep water shelf deposit, with lithology of black shale and a longitudinal thickness 110 m. It is a low-porosity and low-permeability gas reservoir with a high content of brittle minerals. The in-situ stress is moderate and the fracturability is good, and three sets of development layers can be divided vertically. The reserve scale is 1700 × 10⁸ m³, which has a good development resource base. In the 194-X well area, the average single well EUR development for a set of well patterns is 1.08 × 10⁸ m³, only the bottom thickness of 30~50 m is utilized, and the remaining gas accounts for 55.32%. Three sets of well pattern development resources are utilized more fully, and the recovery rate can reach 28.4%. The south slope of Pingqiao Anticline, Dongsheng Anticline and the upper single-well production capacity are implemented, and the gas production of shale gas is predicted to reach 482.8 × 108 m3. The results of the study confirm that the block has a high potential for tridimensional development, which has certain reference significance for increasing the utilization of reserves and expanding the scale of production and construction.