摘要
准噶尔盆地东部侏罗纪处于大型内陆湖盆的东北缘,发育三套稳定分布的煤层,分别位于侏罗系西山窑组下部、八道湾组上部和八道湾组中下部。西山窑组煤层和八道湾组上部煤层形成于湖退型三角洲,煤层厚度大,八道湾组中下部煤层形成于湖侵期滨湖沼泽,厚度薄但分布稳定。准东地区基准面和可容空间变化对聚煤作用及煤系层序结构起着重要的控制作用,侏罗纪受盆地基底差异性沉降的影响,可容空间发生周期性变化,湖退期可容空间向盆地中心迁移,盆地中心及滨岸带以下部位具有较大的可容空间,有利于泥炭保存,形成西山窑组主力煤层和八道湾组上部煤层,这两套煤层在基准面旋回划分中可作为沉积作用的转换面,是时间地层对比的界面。八道湾组中下部煤层具有初始湖泛面性质,可作为层序界面。通过对准东彩31井区煤系基准面旋回进行划分对比,合理地解释了彩31井区西山窑组油藏油气水空间分布关系,在岩性油气藏识别和油藏精细描述方面取得了良好的效果。
The eastern Junggar basin located on the northeastern edge of the large down warped lake basin in Jurassic. Mainly three sets of thick coal layers developed in the east of Junggar basin Jurassic strata, respectively lying at the bottom of Xishanyao group, the upper part and the lower of the middle part of Badaowan group. The coal layer of Xishanyao group and the upper part of Badaowan group were formed in the stage of lacustrine regression delta and they are thick and stable regionally. The coal layer of the lower of the middle part of Badaowan group was formed shore swamp in the stage of lacustrine transgression and it is thin and stability in region. The coal accumulation environment and stacking pattern are controled by base-level and accommodation in the eastern Junggar basin. The accommodation is affected by the structural uplift and basement differential subsidence in the eastern Junggar basin in Jurassic. Accommodation move toward the center of the basin in the process of lacustrine regression and there are bulky accommodation below shoreland where peat are preserved advantageously in the upper section of Badaowan group and the bottom of Xishanyao group. The two sets of coal layers may be acted as the transfer surface of sedimentation. The coal layer of the down of the middle part of Badaowan group may be regard as first flood surface of lacustrine and sequence boundary. Based on accurate correlation of the high-resolution sequence stratigraphy, distribution regularity of oil, gas and water of Xishanyao group reservoir can be explained reasonably in the Well CAI 31 area. It has obtained a good effect on the identification of subtle reservoir and precise reservoir description.
出处
《沉积学报》
CAS
CSCD
北大核心
2006年第3期378-386,共9页
Acta Sedimentologica Sinica
关键词
含煤岩系
沉积环境
基准面
可容空间
高分辨率层序
coal measures
sedimentray environment
base-level surface
accommodation
the high-resolution sequence stratigraphy
