哈密坳陷四道沟油气藏特征及成藏分析

ANALYSES OF THE FORMATION CONDITIONS OF THE HYDROCARBON POOL IN THE SIDAOGOU REGION OF THE HAMI DEPRESSION

四道沟低产油气藏是目前在哈密坳陷内钻探众多构造圈闭后所发现的唯一油气藏。通过对油藏构造、储层特征和油气成藏分析表明 ,四道沟构造存在二期油气运移与聚集 ,第一期形成类似哈 2井三叠系和侏罗系砂岩储层中的沥青 ,它来自三堡凹陷源岩生成的油气 ;第二期为四道沟构造上哈 2、哈 3井储层近源捕获的油气。三堡凹陷源岩在中侏罗统西山窑组沉积以后曾有较大规模的油气生成与运移 ,油气运移路线主要是向东或东北方向。储层物性差、裂缝不发育 ,早期油藏被破坏 ,后期油气源供给不足是四道沟构造上哈 2、哈 3井油气低产的主要原因。该地区下一步油气勘探应围绕三堡生油凹陷 ,以寻找未遭破坏的早期油气藏为勘探方向 ,以三叠系与侏罗系不整合附近的构造圈闭、地层圈闭。

Sidaogou is the only locality to discover a little oil and gas in the exploration of the Hami Depression. Analyses of the formation conditions of the hydrocarbon pool, structural and reservoir features show that the Sidaogou structure had two periods of migration and accumulation of oil and gas. The first period of migration and accumulation came from the hydrocarbon formed in the source rock of the Sanbao Depression and formed the asphalt in the sandstone reservoir of Triassic and Jurassic in the Well Ha 2. The second period came from the hydrocarbon formed in the source rock of Triassic round about the Well Ha 2 and Ha 3 and formed the hydrocarbon pool in Sidaogou. The oil gas in the Sanbao Depression migrated and accumulated on a large scale after the rocks of the Xishanyao Formation of Middle Jurassic was deposited. The direction of migration was to east and northeast. In the end of the paper, the authors point out the primary reason for producing a little oil and gas in the Well Ha 2 and Ha 3 and the main direction for the future petroleum exploration.