四川盆地志留系龙马溪组页岩与美国Fort Worth盆地石炭系Barnett组页岩地质特征对比

摘要

Based on the characteristics of sedimentation, geochemitry, structure evolution and hydrocarbon generation, we compared Carboniferous Barnett Formation shale(BFS) in Forth Worth Basin(United States)with Lower Silurian Longmaxi Formation shale(LFS)in Sichuan Basin(China).There are good shale gas exploring prospects of LFS in Sichuan basin, especially in southern parts. Two sets of source rocks are the similar depositional environments, thickness, korogen types ( Ⅰ ～ Ⅱ t)and hydrocarbon generation processes. But Barnett shale are much richer TOC content (3～13％), brittle minerals and micropores more development; Longmaxi Formation shale are relatively deeper burial depth (commonly 2000～4000m) ,richer clay mineral content, higher thermal maturity (generally Ro＞2％),larger amplitude uplift and quick rising rates (3000m/80Ma).%从沉积学、地球化学、生烃演化、构造演化等方面,对美国Fort Worth盆地石炭系Barnett页岩和四川盆地下志留统龙马溪组页岩进行了对比性研究,发现四川盆地志留系,特别是川南志留系页岩气具有较好的勘探前景.2套烃源岩共性与个性共存,具有相似的沉积背景、厚度、有机质类型(Ⅰ～Ⅱ)和生烃演化史.但是,Barnett页岩TOC值较高(30%-13%)、相对富集脆性矿物、页岩的微孔隙发育;龙马溪组页岩埋藏较深(一般2000-4000m)、相对富集粘土矿物,且具有较高的成熟度(普遍Ro>2%)、较大的隆升幅度和较快的隆升速率(3000m/80Ma).