为探索页岩气富集成藏特征与勘探潜力,以黔西下石炭统页岩为研究对象,基于2口调查井和2口探井资料重点从地层层序及沉积相、页岩赋存特征、成藏条件及有利区评价等方面进行剖析,研究表明：①黔西下石炭统页岩沉积受北西—南东向水城—紫云断裂控制和水城—六枝隆起构造影响,划分为威宁—水城沼泽—潟湖过渡相沉积区和水城—紫云浅水陆棚海相沉积区,形成威宁、紫云2个沉积中心,沉积厚度介于30~200 m,研究区威宁—水城页岩沉积厚度为119 m,底界埋深介于1 500~3 000 m,为勘探有利区;②受多期构造影响和同沉积控制,褶皱、断层共生组合控气成藏特征在该区较发育,为典型的逆断层封堵背斜组合构造控气成藏模式;③平面上,威水背斜与水城—紫云断裂所形成的构造作用带是威宁—水城区域下石炭统旧司组页岩气富集有利区,面积约为944 km²;垂向上,至少存在3套富有机质页岩含气层,具有较好的勘探潜力。

In order to explore the characteristics of rich accumulation and the exploration potential of transitional shale gas, the lower Carboniferous shale in southern Guizhou is taken as the research object. Based on the data of two investigation wells and two exploration wells, the analysis is conducted from the aspects of stratigraphic sequence and sedimentary facies, occurrence characteristics of shale, accumulation conditions and favorable area evaluation. The research result shows that: ① The lower Carboniferous shale deposits in western Guizhou are controlled by the NW-SE Shuicheng-Ziyun synsedimentary fault and the Shuicheng-Liuzhi uplift partition, which can be divided into weining shuicheng tidal flat lagoon-transition sedimentary facies and Shuicheng-Ziyun shallow-water shelf marine sedimentary facies, forming Weining and Ziyun depositional central areas with deposition thickness ranging from 30 m to 200 m. The sedimentary thickness of Weining-Shuicheng is 119 m, and the embedded depth of floor is between 1 500 m and 3 000 m, which is a favorable area for exploration. ② Influenced by multi-stage structure and controlled by syndeposition, the gas accumulation type controlled by the combination of folds and faults is relatively developed in this area, which is a typical gas accumulation mode controlled by the structure of anticlinal combination blocked by reverse fault. ③ On the plane, the accumulation zone of Weishui anticline and Shuicheng-Ziyun fault structure is a favorable exploration area for shale gas research in Weining-Shuicheng, the sedimentary center of Jiusi Formation, with an area of about 944 km². There are at least three sets of organic-rich shale gas bearing beds vertically in the shale, which have good exploration potential