不同压裂规模下煤储层缝网形态对比研究——以延川南煤层气田为例  

Comparison of seam network morphology in coal reservoirs under different fracturing scales:A case of Yanchuannan CBM Gas Field

作　　者：刘晓[1,2] LIU Xiao(Sinopec Linfen Coalbed Methane Company,Linfen,Shanxi 041000,China;Sinopec Key Laboratory of Deep Coalbed Methane Exploration and Development,Nanjing,Jiangsu 210094,China)

机构地区：[1]中国石化临汾煤层气分公司,山西临汾041000 [2]中国石化深层煤层气勘探开发重点实验室,江苏南京210094

出　　处：《油气藏评价与开发》2024年第3期510-518,共9页Petroleum Reservoir Evaluation and Development

基　　金：国家自然科学基金面上项目“深部煤层气赋存态调整分配及释放产出机制”(42272195);中国石化科技项目“华东探区深部煤层气富集规律与有效开发技术”(P23205)。

摘　　要：以大砂量、大液量为特点的储层改造技术推动深层煤层气开发取得突破,煤层气增储上产保持着良好势头。为探索深部煤储层水力压裂过程中裂缝扩展形态,在鄂尔多斯盆地延川南煤层气田开展不同压裂规模煤储层改造的矿场试验,对比分析压后裂缝扩展形态和储层改造面积,查明了不同类型气井、不同施工规模下裂缝形态的差异性,分析投产后的产气效果,形成了适合研究区深部煤储层改造工艺。结果表明:①低效老井多次中等规模压裂、新井多次大规模压裂和新井单次超大规模压裂均能有效延伸裂缝长度、扩大储层改造面积,但缝网形态存在较大差异。受排采过程和诱导应力影响,低效老井经多次中等规模压裂后,形成主裂缝延伸、次裂缝扩展的“玫瑰花”型缝网;新井压裂改造后形成的缝网形态呈“长椭圆”型,但单次超大规模的液体使用效率更高,相同规模下裂缝半长和改造面积更大。②随压裂次数增加,裂缝半长和改造面积均呈对数增加的趋势,且有明显的递减效应,试采证实2次大规模压裂施工具有良好的经济性,研究结果为井网部署提供了依据。以柴油为动力来源的压裂设备较难适应提升规模后的连续施工,电驱动压裂装置是未来整装煤层气田开发的可靠途径。Significant advancements in deep Coal Bed Methane(CBM)development have been achieved through the adoption of reservoir reforming technology,characterized by the utilization of large sand volumes and large fracturing fluid volumes in Yanchuannan CBM Gas Field of Ordos Basin.This study conducts field tests on coal reservoirs with varying fracturing scales to explore the patterns of fracture expansion post-hydraulic fracturing and assesses the resultant reservoir reform areas.The analysis identifies distinct fracture patterns across different types of gas wells and fracturing scales,examines the impacts on gas production post-commissioning,and develops fracturing technology tailored to Yanchuannan CBM Gas Field.Multiple moderate-scale fracturing interventions in inefficient old wells and large-scale fracturing in new wells effectively extend fracture lengths and expand the area of reservoir reconstruction.However,the morphology of the resulting fracture networks varies significantly.Inefficient old wells subjected to multiple medium-scale fracturing develop a“rose-shaped”fracture network with primary and secondary fractures,whereas new wells exhibit a“long elliptical”fracture pattern.Notably,the use of a single ultra-large-scale fracturing fluid achieves greater efficiency,producing longer half-length fractures and larger renovation areas under the same scale. The fracture half-length and renovation area demonstrate a logarithmic increase with the frequency of fracturing,significantly enhancing the efficiency. Economic evaluations of trial production confirm that two large-scale fracturing operationsare economically viable, providing a foundation for future well network deployment. Fracturing equipment powered by dieselstruggles to adapt to continuous operations at scaled-up levels, suggesting that electric-driven fracturing devices present a reliablealternative for the sustainable development of integrated CBM gas fields. These insights not only enhance understanding of fracturedynamics in deep CBM reservoi

关 键 词：延川南气田 深层煤层气 压裂规模 裂缝监测 缝网形态 

分 类 号：TE357[石油与天然气工程—油气田开发工程]