准噶尔盆地百口泉地区白碱滩组沉积相新认识
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摘要
关于准噶尔盆地百口泉地区上三叠统白碱滩组的砂、砾岩,前人普遍认为是三角洲前缘沉积,主要依据是与砂砾岩互层的泥岩为还原色,认为还原色代表水下还原环境沉积。但大量的岩心观察以及测井、录井和地震资料分析表明,白碱滩组的砂、砾岩储集层主要为辫状河沉积,仅少数为三角洲前缘沉积。大部分与砂、砾岩互层的泥岩虽为暗色,但含有大量植物根、杆、茎、叶等化石,甚至夹煤层,白碱滩组自下而上是一个逐渐变浅的沉积旋回,其下段为湖泊沉积,中段为三角洲沉积,上段为辫状河沉积。研究区辫状河沉积的砂体呈条带状,粒度较粗,泥质含量较低,储集物性较好,形成重要的含油层;而三角洲前缘砂体呈席状,粒度较细,泥质含量较高,储集层物性较差,目前尚未发现油层。
Previous studies regarded the glutenite of Baijiantan formation of the Upper Triassic in Baikouquan area in Junggar basin as deposits of the delta front,and the main basis was that the mudstone interbedded with glutenite was in reduction color which represents underwater reduction environment deposits.But the analyses of a large amount of core observation,well logs,logging data and seismic information indicate that the glutenite reservoir of Baijiantan formation is dominated by braided fluvial deposits,a few belong to delta front deposits.The colors of most mudstones interbeddedd with the glutenite are dark,because they contain a lot of fossils of many plant roots,rods,stems,leaves,and even have coal seam interbed.Also,the Baijiantan formation is a sedimentary cycle gradually becoming shallow from the top to the bottom,the lower part is lake deposit,the middle is delta deposit and the upper is braided fluvial one.The sands of braided fluvial deposits in the studied area are characterized by strip,coarse granularityand,low shale content and good reservoir quality,in which the main oil-bearing reservoirs have been formed and found;while sands of the delta front characterized by sheet,fine grain size,high shale content and poor reservoir quality,in which oil-bearing zone has not been found.
Previous studies regarded the glutenite of Baijiantan formation of the Upper Triassic in Baikouquan area in Junggar basin as deposits of the delta front,and the main basis was that the mudstone interbedded with glutenite was in reduction color which represents underwater reduction environment deposits.But the analyses of a large amount of core observation,well logs,logging data and seismic information indicate that the glutenite reservoir of Baijiantan formation is dominated by braided fluvial deposits,a few belong to delta front deposits.The colors of most mudstones interbeddedd with the glutenite are dark,because they contain a lot of fossils of many plant roots,rods,stems,leaves,and even have coal seam interbed.Also,the Baijiantan formation is a sedimentary cycle gradually becoming shallow from the top to the bottom,the lower part is lake deposit,the middle is delta deposit and the upper is braided fluvial one.The sands of braided fluvial deposits in the studied area are characterized by strip,coarse granularityand,low shale content and good reservoir quality,in which the main oil-bearing reservoirs have been formed and found;while sands of the delta front characterized by sheet,fine grain size,high shale content and poor reservoir quality,in which oil-bearing zone has not been found.
引文
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[2]金振奎,王兆峰,顾军锋.准噶尔盆地东部台13井区八道湾组水流及砂体延伸方向[J].新疆石油地质,2010,31(4):356-357.
[3]Sun Xiaofang,Jin Zhenkui.Braided river and distributionpatterns of sandbodies of Jurassic Badaowan formation in BlockT13 of Jungaer basin[J].Mining Science and Technology,2010,20(3):446-452.
[4]金振奎.关于三角洲沉积模式的新认识[A].第十一届全国古地理学及沉积学学术会议论文摘要集,2010:24-25.
[5]金振奎,何苗.关于三角洲沉积模式的新认识[J].新疆石油地质,2011,32(5):443-446.
[2]金振奎,王兆峰,顾军锋.准噶尔盆地东部台13井区八道湾组水流及砂体延伸方向[J].新疆石油地质,2010,31(4):356-357.
[3]Sun Xiaofang,Jin Zhenkui.Braided river and distributionpatterns of sandbodies of Jurassic Badaowan formation in BlockT13 of Jungaer basin[J].Mining Science and Technology,2010,20(3):446-452.
[4]金振奎.关于三角洲沉积模式的新认识[A].第十一届全国古地理学及沉积学学术会议论文摘要集,2010:24-25.
[5]金振奎,何苗.关于三角洲沉积模式的新认识[J].新疆石油地质,2011,32(5):443-446.
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