准噶尔盆地克拉美丽气田石炭系火山岩储层特征及成岩演化

通过岩心观察、薄片鉴定和扫描电镜分析等,研究准噶尔盆地克拉美丽气田石炭系火山岩储层特征。在此基础上,结合埋藏史、热史和烃类充注史等,确定地质演化背景下的火山岩成岩和孔隙演化动态过程。结果表明,该区火山岩储层储集空间类型多样,主要由次生溶蚀孔隙和构造裂缝构成,总体属于中孔低渗。火山碎屑岩、火山熔岩和次火山岩物性较好,火山-沉积碎屑岩物性较差。火山岩孔隙结构分为3类,其空间分布受构造、不整合面和岩性控制。火山岩储层主要发育7种成岩作用,其成岩演化经历了同生成岩阶段、表生成岩阶段和埋藏成岩阶段3个阶段,火山岩储集性能与表生成岩阶段风化淋滤作用密切相关,埋藏成岩阶段深埋溶蚀作用进一步增大了火山岩储集空间。

Reservoir characteristics and diagenetic evolution of Carboniferous volcanic rock in Kelameili gas field of Junggar Basin

The reservoir characteristics of the Carboniferous volcanic in Kelameili gas field of Junggar Basin were studied using core observations, microscopic identification and scanning electron microscope analysis. Combining with burial history, thermal history and hydrocarbon infilling history, the diagenetic evolution and the pore dynamic evolution of the volcanic reservoir were derived. The results show that there are many types of volcanic reservoir spaces, but the secondary dissolved pores and structural fractures are the most abundant types. The reservoir is in general medium porosity and low in permeability. The reservoir property of pyroclastic rock, volcanic lava and subvolcanic rock is better than that of volcanic sedimentary-pyroclastic rocks. The volcanic pore structure can be divided into three categories. Its spatial distribution is controlled by structure, unconformity and lithology. There are mainly seven types of diagenesis. The diagenetic evolution of the volcanic reservoir can be divided into three stages, syngenetic diagenesis stage, exodiagenesis diagenesis stage and burial diagenesis stage, respectively. The reservoir capacity is closely related to weathering and leaching in the exodiagenesis diagenesis stage. The dissolution in burial diagenesis stage may have further enlarged the volcanic reservoir space.