中国西南镇雄-赫章地区筇竹寺组高演化页岩气勘探方向

勘探实践表明中国西南的镇雄-赫章地区下寒武统筇竹寺组页岩气成藏条件优越,受强改造与高演化制约,筇竹寺组页岩气勘探尚未获得突破。为寻找热演化程度相对较低的有利保存区,基于钻井、露头、地震资料,通过编制关键期次岩相古地理图及古地质图,结合各沉积-剥蚀分区典型埋藏史分析,精细刻画镇雄-赫章地区沉积-剥蚀分区特征。结果表明:镇雄-赫章地区发育加里东期-海西期古隆起,控制二叠纪前沉积充填过程,沉积-剥蚀差异性明显。其中Ⅰ区及Ⅱ区缺失层系较多,且热演化间断时间长,热演化程度相对较低,为筇竹寺组页岩气有利勘探区。古隆起及周缘地区为海相高演化页岩气勘探的有利指向。

Exploration direction of highly mature shale gas from Qiongzhusi Formation in Zhenxiong-Hezhang area of Southwest China

The exploration practice shows that the shale gas accumulation condition of the Lower Cambrian Qiongzhusi Formation in the Zhenxiong-Hezhang area is superior.Being limited in the strong transformation and high maturity,the shale gas exploration in Qiongzhusi Formation has not been won a breakthrough.In order to search out the favorable preservation areas with relatively low thermal evolution degree,based on the drilling,outcrop and seismic data,through plotting the lithofacies-paleogeographic map and ancient geological map of the key periods,and combined with the analysis of the typical buried history of every deposition-denudation division,this paper describes the characteristics of the sedimentary-denudation divisions in the Zhenxiong-Hezhang area.The results show that there develops the Caledonian-Hercynian ancient uplift in this area,which controls the sedimentary process before Permian and that the deposition-denudation difference is obvious.In District Ⅰ and District Ⅱ,there is lack of more strata,the thermal evolution intermittent time is long,and the Permian thermal evolution degree is relatively low,so District Ⅰ and District Ⅱ are the favorable exploration areas of the shale gas in Qiongzhusi Formation.The ancient uplift and peripheral regions are the favorable targets for the explorating the highly mature shale gas.