准噶尔盆地岩性油气藏勘探成果和方向

Exploration and targets for lithologic reservoirs in Junggar Basin,NW China

准噶尔盆地已发现了12个陡坡型扇体油气藏,在缓坡型沉积体系中也发现石南4井区、石南21井区、石南26井区侏罗系头屯河组辫状河道砂体岩性油藏以及中拐凸起三工河组和白家海凸起西山窑组岩性油气藏。准噶尔盆地经历了多旋回构造运动和多期湖平面升降,是形成各类岩性圈闭的基础;多源、多灶为岩性油气藏的形成提供了雄厚的烃源保障;多期断裂活动、多个区域性不整合面发育为岩性圈闭多期成藏构筑了良好的油气输导系统,岩性油气藏勘探潜力很大。但目前准噶尔盆地岩性油气藏探明率仅4%左右,在已探明油气储量中所占比例尚不到22%。认为目前准噶尔盆地岩性油气藏勘探主要有五大领域:西北缘二叠系、三叠系陡坡型扇体;腹部侏罗系三工河组、西山窑组大型缓坡型三角洲前缘河口坝和滑塌扇岩性圈闭;陆西和阜东斜坡头屯河组(或石树沟群)河道砂体岩性圈闭;受车莫低凸起控制的侏罗-白垩系河道深切谷地层-岩性圈闭;玛湖西斜坡受侏罗纪构造坡折带控制的地层-岩性圈闭。

Twelve steep-slope fan-like reservoirs have been found in Junggar Basin. In the gentle-slope depositional system, such petroleum reservoirs as braided channel sandbody in Jurassic Toutunhe Formation in Well Feild Shinan 4, Shinan 21 and Shinan 26, and hydrocarbon reservoirs of Sangonghe Formation in Zhongguai High and Xishanyao Formation in Baijiahai High, have also been found. Having experienced polycyclic tectonic movements and multistage vibratory movements of lake planes, Junggar Basin has been provided with good bases for the formation of various lithologic traps. Multitudes of hydrocarbonsources and kitchens have provided abundant hydrocarbon sources for the formation of lithologic reservoirs. Multistage faulting activities and the development of multi-regional unconformable surfaces have constructed an excellent oil and gas transporting system for multi-stage hydrocarbon accumulation in the depositional traps. Therefore there is great potential for exploration of lithologic reservoirs. The identifying ratio of the lithologic reservoirs in Junggar Basin only accounts for about 4%. The reserves from such reservoirs account for less than 22% of the total proved hydrocarbon reserves. It is considered that there are currently mainly five provinces for the exploration of lithologic hydrocarbon reservoirs in Junggar Basin： Permian and Triassic steep-slope fan body in the NW margin, large gentle-slope delta front mouth bar and slumping fan of Jurassic Sangonghe Formation and Xishanyao Formation in the hinterland, channel sand body of Toutunhe Formation （or Shishugou Formation） in Luxi and Fudong slope, Jurassic- Cretaceous channel-incised valley stratigraphic-lithogic trap dominated by Chemo High, and stratigraphic-lithologic trap dominated by Jurassic structural slope belt in Western Slope of Mahu.