太原西山煤田多期次异常热事件“时-空-温”配置关系及其对煤储层孔-裂隙系统的影响

It is a common phenomenon that sedimentary basins experienced multiple abnormal thermal events, which significantly controlled the mineralization/accumulation of oil, nature gas, coal and coal-measure gas. Exploration and development practice of coal bed methane in Xishan coalfield, Taiyuan indicated rapidly varying coal rank and strong heterogeneity of reservoir properties. It also indicated that the coalfield underwent multiple thermal events since Triassic period. Spatial and temporal distribution of these abnormal thermal events and their impact on differential pore-fracture system evolution become a research topic requiring immediate attention. Take Xishan coalfield as a research object, this proposed research will start with identification of multiple thermal events. Based on the organic matter vitrinite reflectance measurements, fission-track and U-Th/He of minerals (i.e. apatite, zircon and sphene), authigenic minerals and vein minerals dating as well as fluid-inclusion analysis will be performed and used in combination to establish the time-space-temperature configuration of multiple abnormal thermal events. Then, pore-fracture system with different configuration of thermal events will be investigated to understand the controlling mechanism of thermal on reservoir heterogeneity. The research is expected to provide a feasible approach to reconstruct the thermal history of sedimentary basins with multiple thermal events, and to provide new insights on the factor and mechanism of coal reservoir heterogeneity.

沉积盆地多期次异常热事件共存是一种普遍现象，其对油气、煤及煤系气等多种能源矿产的成矿（藏）有重要的控制作用。太原西山煤田煤层气勘探开发实践表明，煤田煤级变化快、储层非均质性强。三叠纪以来，煤田经历了多期次异常热事件，这些异常热事件的时空分布及其对煤储层孔-裂隙系统差异性发育的影响亟待探究。本项目以太原西山煤田为研究对象，从盆地多期次异常热事件识别入手，在有机质镜质组反射率分析的基础上，应用磷灰石/锆石/榍石矿物裂变径迹和U-Th/He定年、自生温标矿物定年、脉体矿物定年和流体包裹体分析等多种方法结合，研究多期次异常热事件“时-空-温”分布特征及配置关系，进而探讨不同异常热事件配置方式对煤储层孔-裂隙发育的影响，揭示煤储层非均质性成因的热控制机理，从而为多期次异常热事件共存盆地热演化史恢复提供可行的途径，为煤储层非均质性成因机理提供新的视角。