地层流体系统分异与煤系气开采互动机制

Three kinds of gases in coal series, including coalbed methane , tight sandstone gas and shale gas, are an important unconventional gas resources for China, but their scale joint developments have not been realized in China until now because of ambiguous mechanism and degree of inter-layer interference due to multiple fluid system widely existing in coal series. Taking Carboniferous-Permian coal series in the east of Ordos basin as example, we will analyze sedimentary sequence and cyclicity of reservoir properties, construct geology model of reservoir(production layer) combinations and their properties restrained by key water and gas barrier layers, discuss geological features, classification index and function, and their control factors, establish fluid system developing mode, investigate fluid occurrence phase and output process differences, explain the interaction mechanism and model among fluid systems under differential controls of gas content, sorption, permeability, liquid supplement capacity and reservoir pressure, and put forward quantitative index and evaluation method for inter-layer interference of co-development of three kinds of gases in coal series. Those results will be applied on comprehensively efficient and orderly development of natural gas in coal series.

以煤层气、致密砂岩气和页岩气共生为特征的煤系“三气”是我国重要的非常规天然气资源，然而煤系多套多类型流体压力系统叠置发育导致合层开发系统间干扰发生的作用机制及程度认识不清，制约了 “三气”资源综合开发。本研究以鄂尔多斯盆地东缘石炭-二叠纪含煤地层为例，分析含煤地层的沉积序列及其导致的储层物性旋回式发育特征，建立以阻水隔气关键层为约束的煤系储（产）层组合及其物性旋回地质模型，探讨含煤地层流体系统的地质显现特征、划分指标与函数及其地质控制因素，建立含煤地层流体系统分异及其类型发育模式，查明含煤地层“三气”赋存态和产出过程差异，阐释叠置流体系统含气性、吸附性、渗透性、供液强度及储层流体压力等差异控制下流体系统间互动机制与模型，提出煤系“三气”共采系统间干扰程度量化评价指标和方法。上述研究成果对煤系气高效有序开发具有重要的应用价值。

我国煤系气开发规模性仍然较小，与其资源量严重不匹配，科学研究依然难以满足国家对其的需求。“煤系多类型叠置流体系统发育模式不明及其间的互动机制与程度不清”这一关键科学问题限制了煤系气产能的充分释放。结合煤系气综合勘探与开发试验工程，研究阐释了含煤地层的沉积序列特点，建立了煤系多类型储层三维地质模型，确定了关键层及其发育模式，建立以关键层为约束的煤系储（产）层组合及其物性旋回地质模型；查明了含煤地层流体的组成和压力空间分异特点，划分了叠置流体系统，建立了含煤地层流体系统分异模式；查明了煤系流体赋存特征和产出过程差异，探讨了影响产出过程差异关键因素及其作用阈值，阐释了叠置流体系统间互动关系并构建了模型，提出了煤系气共采系统间干扰程度量化评价指标和方法，评价了煤系流体系统合采兼容性，实现了基于产层贡献判识的煤系气合采可行性定量评价，提出跨流体系统以及同一流体系统内部的产层组优化方案。上述研究为煤系气综合勘探开发部署提供了指导思想和基本原则。培养博士、硕士研究生8名，发表学术论文24篇（其中SCI收录15篇、EI收录1篇），获得发明专利授权3项和软件著作权1项，出版专著1部，项目负责人入选2019年江苏省高校青蓝工程优秀青年骨干教师。