思茅盆地页岩气地质条件及资源潜力分析

Analysis of shale gas geological condition and resource potential in Simao Basin

根据野外调查及样品测试,从富有机质页岩的地化特征、物性特征及保存条件等分析了思茅盆地页岩气地质条件。研究表明:思茅盆地发育下密地组、羊八寨组、挖鲁八组及和平乡组四套暗色页岩;其中,羊八寨组页岩累计厚度普遍大于100 m,TOC平均为1.06%~2.54%,R o平均为1.81%~3.47%,有机质类型主要为Ⅱ2—Ⅲ型,脆性矿物含量平均为49.5%,为思茅盆地页岩气有利层段。景谷洼陷南部和普文洼陷受深大断裂、地层抬升剥蚀、岩浆岩和变质岩带影响较小,盖层厚度大,页岩气保存条件相对较好。思茅盆地与相邻呵叻盆地具有相似的油气地质条件,具有一定的页岩气资源潜力,值得开展进一步的勘探研究工作。最后,综合考虑页岩分布、有机地化条件和保存条件,预测页岩气有利靶区主要位于勐班—德化及普文—象明一带。

Based on field investigation and sample testing,the geological condition of shale gas in Simao Basin is analyzed from the geochemical characteristics,physical properties and preservation condition of organic rich shale.The study result shows that there are developed for four sets of dark shale in Simao Basin,Xiamidi Formation,Yangbazhai Formation,Waluba Formation and Hepingxiang Formation.Among them,because the cumulative thickness of shale in Yangbazhai Formation is generally greater than 100 meters,with an average TOC of 1.06%-2.54%and an average Ro of 1.81%-3.47%,and the organic matter type is mainly II2-3 type,with an average brittle mineral content of 49.5%,Yangbazhai Formation is a favorable shale gas layer in Simao Basin.The south part of Jinggu Depression and Puwen Depression are less affected by deep faults,stratigraphic uplift and erosion,magmatic rocks and metamorphic rock belts,and there is a thick cover rock layer,resulting in relatively good condition for shale gas preservation.Simao Basin has a similar oil and gas geological condition to the adjacent Khorat Basin,and there is a certain shale gas resource potential,which is worth further exploration and research work.Finally,for the comprehensive consideration of shale distribution,organic geochemical condition,and preservation condition,it is predicted that the favorable target area for shale gas is mainly located in the Mengban-Dehua and Puwen-Xiangming areas.