渝东南常压与高压页岩气典型差异性分析及效益开发对策

Typical difference analysis and benefit-oriented development countermeasures of normal and high pressure shale gas in southeastern Chongqing

周德华 何希鹏 张培先

ZHOU Dehua HE Xipeng ZHANG Peixian

1. 中国石化 油田勘探开发事业部, 北京 100728; 2. 中国石化 华东油气分公司, 南京 210019; 3. 中国石化 华东油气分公司 勘探开发研究院, 南京 210019

1. SINOPEC Oilfield Exploration and Development Division, Beijing 100728, China; 2. SINOPEC East China Branch Company, Nanjing, Jiangsu 210019, China; 3. Research Institute of Exploration and Development, SINOPEC East China Branch Company, Nanjing, Jiangsu 210019, China

渝东南地区处于四川盆地东南缘的盆缘转换带，发育常压、高压两种类型页岩气藏。为提高常压页岩气开发效益，从常压与高压页岩气典型差异性分析入手，通过开展钻井、岩心观察、实验分析、成藏条件及生产动态等研究，结合渝东南地区页岩气勘探开发实践，明确了常压页岩气具有优质页岩厚度较薄、孔隙度较低、保存条件较差、含气量中等的典型地质特点。常压页岩气富集受沉积相带、保存条件及地应力场控制，受多期构造改造及差异性抬升影响，形成机理复杂，具有初产较低、稳产期短、递减较慢、返排率高的生产特征。与高压页岩气在地质特点、富集规律、形成机理及生产规律等方面具有明显的地质特征差异性。针对渝东南地区常压页岩气资源品位较差的问题，提出了常压页岩气效益开发的4个关键对策：(1)深化基础地质研究，明确富集规律和甜点目标；(2)建立变井距、长水平段、小夹角、强改造、低高差、控压差的开发技术政策，提高单井产量；(3)加大低成本钻井和高效压裂等工程工艺创新，实现提速提效降本；(4)创新体制机制建设，打造高效组织运行模式。4个关键对策有效促进了常压页岩气由资源向储量、从储量向效益的转变，助力渝东南常压页岩气实现规模效益开发。

Southeastern Chongqing is located in the transition zone of the southeastern margin of Sichuan Basin. Shale gas reservoirs of normal and high pressure are developed in this area. In order to promote normal pressure shale gas development benefits, starting from the typical difference analysis of normal and high pressure shale gas, through the research of drilling, core observation, experimental analysis, accumulation conditions, and production dynamics, combined with shale gas exploration and development practices in southeastern Chongqing, it is clarified that the normal pressure shale gas has the typical geological characteristics of small thickness of high-quality shale, low porosity, poor preservation conditions, and medium gas content. The accumulation of normal pressure shale gas is controlled by sedimentary facies, preservation conditions, and in-situ stress field. Affected by multi-stage structural transformation and differential uplift, the mechanism of normal pressure shale gas generation is complex, which has the characteristics of low initial production, short stable production period, slow decline, and high flowback rate. There are obvious differences between normal and high pressure shale gas in geological characteristics, enrichment regularities, generation mechanism, and production law. Considering the poor grade of normal pressure shale gas resources in southeastern Chongqing, four key countermeasures for the benefit-based development of normal pressure shale gas are put forward: (1) The basic geological research is furthered and the enrichment regularities and sweet spots are clarified. (2) The development technology of variable well spacing, long horizontal section, small inclined angle, strong transformation, low height difference and controlled pressure difference is established to increase the production of single well. (3) The innovation of engineering technology such as low-cost drilling and efficient fracturing is increased to achieve speed acceleration, efficiency improvement, and cost reduction. (4) The institutional mechanism is innovated and an efficient organization and operation mode is created. The four key countermeasures effectively promote the transformation of normal pressure shale gas from resources to reserves and from reserves to benefits, facilitating the efficient development of normal pressure shale gas in southeastern Chongqing.

国家科技重大专项(2016ZX05061)和中国石化科技部项目(P21087-6)联合资助。

https://doi.org/10.11781/sysydz2023061109