【摘要】 通过对西加拿大盆地页岩油气藏地质条件的分析,发现中国东部济阳坳陷页岩油气成藏条件具备与之可对比的3个特点。一是西加拿大盆地页岩油气储层的沉积环境多为海相,页岩分布范围广、均质性好,在落基山脉(南北轴向)向东侧翘倾的整个前陆盆地范围内形成了一个大范围的储集背景;而济阳坳陷页岩层多为陆相湖泊成因,具有典型的分隔-孤立盆地背景,沉积层完整,源-汇对称吻合度高。二是西加拿大盆地海相页岩生烃母质存在2种类型,Ⅰ型和Ⅰ—Ⅱ型干酪根多来源于海洋浮游生物藻类,Ⅱ—Ⅲ型干酪根多来源于陆表海环境沉积的孢子花粉;而济阳坳陷陆相页岩的生烃母质以Ⅰ—Ⅱ型干酪根为主,多为浮游生物轮藻、沟鞭藻、颗石藻等。三是在西加拿大盆地泥盆系沉积层中普遍见到有机质热演化孔,岩石密度较低;而在济阳坳陷的页岩中则少见该类孔隙,且由于页岩层处于成岩中—晚期而呈致密结构。此外,西加拿大盆地与济阳坳陷页岩油气的开发条件也存在较大差异,西加拿大盆地页岩地层中含有比例较大的长英质刚性颗粒,岩石脆性、可压性等工艺-地质条件较好;而济阳坳陷页岩组分中多含硬度较低的碳酸盐矿物,刚性颗粒含量极低,难以建立后期压裂投产所必备的支撑结构。济阳坳陷陆相页岩油气的"甜点"应聚焦于韵律层理缝隙带、曲率变化形成的不规则裂缝及矿物结晶和有机质热解形成的微-纳米孔。更多还原

【Abstract】 Through the analysis of the geological conditions of shale oil and gas reservoirs in Western Canadian Basin,it is found that the oil and gas enrichment conditions in Jiyang Depression have three comparable characteristics. First,the sedimentary environment of shale oil and gas reservoirs in Western Canadian Basin is mostly marine facies,in which the homogeneous shale distributes widely and forms a large accumulation in the whole foreland basin which tilts eastward in the Rocky Mountains(north to south direction). However,the shale reservoirs in Jiyang Depression are mostly form in continental lacustrine environment,which is the typical separated-isolated basin with complete sedimentary layers,and with high source-sink symmetry coincidence. Second,there are two types of hydrocarbon generating parent material in the marine shale of the Western Canadian Basin. TypeⅠand Type Ⅰ-Ⅱ kerogens are mostly from marine plankton and algae,TypeⅡ-Ⅲ kerogens are mostly from spore pollen deposited in surface marine environment. While Type Ⅰ-Ⅱ kerogens are the major hydrocarbon-generating parent materials of continental shale in Jiyang Depression,and they are mostly from phytoplankton,dinoflagellates,coccolites,etc. Third,organic pores from thermal evolution is commonly developed in low-density Devonian sediments of Western Canadian Basin,while they are rarely found in shale of Jiyang Depression because the shale is in the middle-late stage of diagenesis and develops compact structure. In addition,the development conditions of shale oil and gas in West Canadian Basin and Jiyang Depression are quite different. The shale strata in Western Canadian Basin contain a large proportion of rigid felsic quartz particles,and the brittleness and compressibility of rocks are better,while the shale components in Jiyang Depression is comprised of more carbonate minerals with lower hardness. The content of rigid particles in Jiyang Depression is extremely low,and therefore it is difficult to establish the necessary supporting structure for later fracturing operation. The"sweet spots"of continental shale oil and gas should distributes in rhythmic bedding fracture zone,irregular cracks caused by curvature change,micro-nanopores caused by mineral crystallization and pyrolysis of organic matter in Jiyang Depression.更多还原