准噶尔盆地西北缘红山嘴油田地层水特征与油气藏聚集关系

通过对准噶尔盆地西北缘红山嘴油田地层水平面分布特征和垂向变化规律的研究,揭示了该油田油气运移、聚集规律。红山嘴油田原油来自二叠系风城组和乌尔禾组,原油沿着不整合面和燕山期构造运动形成的近南北向断裂带,从东南向西北方向运移。从油气藏的分布特征和地层水的化学特征对比中得出,地层水的保存环境直接指示了油气藏的成藏环境;地层水所指示的封闭环境,均有良好的油气藏发现。燕山期构造运动断开了红山嘴油田石炭系至白垩系。通过断层两盘的地层水特征对比,发现燕山期运动后所形成的南北向断裂带处于开启状态,红车断裂带北段油气藏封闭性差,出现油气散失;通过原油密度分布与饱和烃气相色谱关系研究,得出红车断裂带北段经过水洗和生物降解后形成红山嘴稠油区。红车断裂带南段,由于白碱滩组巨厚层泥岩盖层的封盖作用,油气藏保存条件较好;在近东西向断层遮挡等情况下,形成了良好的断块油气藏。

Relationship between formation water characteristics and hydrocarbon accumulation in Hongshangzui oilfield in the northwestern margin of the Junggar Basin

The paper describes the plane distribution and vertical variation of formation water of the Hongshangzui oilfield in the northwestern margin of Junggar Basin for the purpose of investigating the hydrocarbon migration and accumulation patterns.Crude oil in Hongshanzui oil field was sourced from the Permian Fengcheng Formation and Wuerhe Formation and migrated along the unconformity and of the nearly S-N trending fault zone that was formed during the Yanshanian movement.Correlation of reservoir distribution with chemical feature of formation water indicates that the environment formation water preservation is an direct indicator of the setting of hydrocarbon accumulation and all of the sealed environments indicated by formation water have oil/gas discoveries.The strata from the Carboniferous to the Cretaceous were faulted by the Yanshanian Movement.The comparison of formation water properties between the hanging wall and foot wall shows that the N-S trending faulted zone formed after the Yanshanian movement is open and the northern segment of the Hongche fault belt has poor sealing condition resulting in loss of hydrocarbon and local light oil reservoirs.Analysis of relationship between crude oil density distribution and saturated hydrocarbon gas chromatography shows that a heavy oil zone was formed in the northern segment of the Hongche fault belt by washing and biodegradation.In contrast,the sou-thern segment of the fault belt has good reservoir preservation conditions due to the sealing of the huge thick mudstone in the Baijiantan Formation.Good fault block reservoir can be formed under the sealing of the E-W trending fault.