沁水盆地南部高阶煤层气成藏规律与勘探开发技术

Enrichment mechanism and exploration and development technologies of high rank coalbed methane in south Qinshui Basin,Shanxi Province

基于对沁水盆地南部高阶煤层气基本地质特征及成藏控制因素的分析,研究其成藏规律与勘探开发技术。勘探开发实践证实研究区煤层气藏具有三大特性:1煤阶高,吸附能力强,资源条件优势明显;2孔隙率低,双峰态孔隙结构,渗流条件瓶颈显著;3储集层压力梯度低,制约产出。在深入分析高阶煤特性基础上,提出了构造、沉积、热动力和水文地质条件"协同、互补、共存"成藏理论,建立了研究区煤层气非富集成藏模式,使成藏界定问题简化且直接指导煤层气开发选区。沁水盆地南部煤层气区块勘探开发形成了五大关键技术体系:1地球物理勘探综合评价技术,2适合于高阶煤储集层的钻完井技术,3储集层改造主体技术,4智能化排采控制技术,5煤层气田的数字化技术,为新区块煤层气产能建设的有序推进提供了技术支撑。

Based on analysis of the basic geologic characteristics and enrichment controlling factors of the high rank coalbed methane （CBM） in south Qinshui Basin in China, its enrichment mode, and exploration and development technologies are studied. Practices on the CBM exploration and development proved that the CBM reservoirs in this study area have the following three major properties： （1） High coal rank, strong adsorption ability, and good resources condition; （2） Low porosity, bimodal porosity structure, and obvious ＂bottleneck＂ of flow condition; （3） low reservoir pressure gradient that can constrain production. Based on deep analysis of high rank coal properties, this study proposes a coexistence and complementarity concept of structure, sedimentary, thermal power and hydro-geological conditions, and establishes a CBM dissipation model, which can simplify CBM enrichment problem and directly guide the region selection of CBM development. Five major critical technical systems have been formed for the CBM exploration and development in south Qinshui Basin： （1） Comprehensive geophyisical exploration and evaluation technologies; （2） Well drilling and completion technologies for high rank coal reservoirs; （3） Major reservoir treatment technologies; （4） Intelligent drainage and production control technologies; （5） Digital technology of coalbed gas field. These have effectively provided technical support for an orderly productivity construction of new CBM blocks.