北非古达米斯盆地石油地质特征及勘探方向

古达米斯盆地位于北非撒哈拉地台,属古生代克拉通内坳陷盆地,整体呈现东高西低,南高北低的构造格局,主要发育北东-南西向低幅构造。盆地共经历了4次大的构造运动,沉积了古生界寒武系-石炭系和中新生界巨厚的沉积盖层,石油地质条件非常优越。盆地内最重要的生油岩是志留系Tanezzuft组和上泥盆统Aouinet Ouenine群放射性海相页岩;共发育6套砂岩储层,主力储层是三叠系砂岩;上三叠统-下侏罗统的蒸发岩和泥页岩沉积在盆地内广泛发育,成为区域盖层,有效封堵了油气。此外盆地内圈闭类型丰富,各成藏要素之间的时空配置关系良好。目前盆地勘探目标是浅层构造圈闭为主,但近年的油气发现表明,在深部远景区、地层圈闭以及盆地利比亚部分的三叠系储层同样具备较大的勘探前景,或将成为下一步重要的勘探方向。

Petroleum geological characteristics and prospecting direction of Ghadames basin in North Africa

Located in North Africa,Ghadames basin belongs to Paleozoic intracratonic depression basin,presenting overall high in east west and low in west,and tectonic framework of high in south and low in north,with NE-SW low-amplitude structure.The basin mainly experienced four big tectonic movements,deposited Paleozoic Cambrian-carboniferous and the Cenozoic sedimentary cap rock cover,being with superior petroleum geological conditions.The most im-portant source rocks are in Silurian Tanezzuft and radioactive marine shale of the upper Devonian Aouinet Ouenine group.A total of six sets of sandstone reservoir have been developed,and the main reservoir is Triassic sandstone.Under the Triassic- Jurassic,the evaporite and mud shale have been widely developed,acting as regional cap rocks,which effectively blocks the oil and gas.In addition,trap types are rich in the basin and the time and space relationship between accumulation elements is good.At present,the exploration targets are the shallow structural traps.However,recent findings suggest that large exploration prospects exist in deep vision area,stratigraphic trap and part of the Triassic reservoir basin,which may become important exploration direction in the next step.