黔西石炭系旧司组页岩气成藏特征及勘探开发启示
Accumulation characteristics and exploration development revelation on shale gas in Jiusi Formation of Carboniferous in Qianxi
-
摘要: 为综合评价贵州省主要页岩层系的页岩气开发潜力,探索页岩气富集成藏关键控制因素及富集规律,以威宁-水城下石炭统旧司组页岩为研究对象,通过该分析区内2口调查井和2口发现井的资料,结合区域地质从构造特征入手分析并提出页岩气富集成藏模式。研究表明:黔西下石炭统旧司组(C1j)页岩平均厚度400 m、含气量为1.5~3.0 m~3/t、有机质成熟度平均2.67%、脆性矿物含量大于60%,垂向至少沉积3套页岩气开发潜力层段;页岩气勘探开发思路由传统的盆地富集向次级断裂控制的凹陷聚集、由负向构造向正向构造转变;"凹陷-隆起-断裂-斜坡"页岩气组合成藏模式是页岩气甜点区优选的有利单元,"逆断层-背斜组合成藏模式"在南方复杂构造区页岩气勘探开发具有指导意义。Abstract: In order to comprehensively evaluate the development potential of the shale gas in the major shale strata in Guizhou Province and to discover the key control factors and enrichment law of the shale gas enrichment accumulation,based on the shale in Jiusi Formation of Weining-Shuicheng Lower Carboniferous as the study object,with the information of two survey wells and two discovered wells within the regional analysis,the enrichment accumulation mode of the shale gas was analyzed and provided in combination of the regional geology and from the structure features. The study results showed that the shale in Jiusi Formation of Qianxi Lower Carboniferous had an average thickness of 400 m,a gas content of 1.5~3.0 m3/t,an organic matter maturity of 2.67 % in average,a brittle mineral content over 60 % and at least three sections of the shale with development potentials vertically deposited. The exploration and development idea of the shale gas was changed from the traditional basin enrichment to the second fractured controlled sunken accumulation and from the negative structure to positive structure. The combined accumulation mode of the “sunken-heave-fracture-slope” shale gas was a favorable unit of the optimization in dessert area of shale gas. "A reverse fault- anticline combined accumulation mode" would have the guide significance to the exploration and development of the shale gas in South China complicated structure area.