乌里雅斯太凹陷南洼洼槽带页岩油气勘探潜力探讨

Exploration Potential of Shale Oil and Gas in Trough Belt of Southern Sag of Ulyastai Depression

乌里雅斯太凹陷南洼槽由北向南发育了三大构造区域:北部的苏布构造、中部的木日格构造、南部的超尔金构造。目前在苏布、木日格构造缓坡带的岩性-地层致密油气藏已获得不同程度的工业油流,而洼槽带的勘探程度较低。2020年在木日格构造洼槽带钻探了T591X井,腾一下亚段、阿尔善组岩性以泥页岩为主,均见到良好的油气显示,气测显示活跃,全烃最大51.73%,其间各类油气显示达172.6m/84层。在大量岩心薄片观察的基础上,结合区域地质背景、录井油气显示、试油情况等,证实其生烃能力及储集空间均具备形成源储共生页岩油气的地质条件,初步计算,生烃总量达3713.45×10^(4)t/km^(2),展示了洼槽带巨大的页岩油气勘探潜力。

Three tectonic regions are developed from north to south in the southern trough of Uriyastai Depression:The Subu structure in the north,the Murege structure in the middle,and the Chaoerjin structure in the south.At present,different degrees of industrial oil flow have been obtained from lithologic-stratigraphic tight reservoirs in the Subu and Murige structure gentle slope belt,but the exploration degree of trough belt is relatively low.In 2020,well T591 X was drilled in Murige tectonic trough belt.The lithology of the lower submember of Tengyi Formation and Aishan Formation is mainly mud shale,and good oil and gas displays were seen.The gas measurement shows active,with the maximum total hydrocarbon of 51.73%,and various oil and gas displays reach 172.6 m/84 layers.Based on the observation of a large number of core thin sections,combined with the regional geological background,logging oil and gas display,oil testing,etc.,it is confirmed that the hydrocarbon generation capacity and reservoir space have the geological conditions for the formation of shale oil and gas co-existing source and reservoir.The preliminary calculation shows that the total amount of hydrocarbon generation is 3713.45×10^(4)t/km^(2),showing the huge potential of shale oil and gas exploration in the trough zone.