基于地震资料判断油气成藏后断裂再活动是否破坏泥岩盖层封闭的方法

为了研究断裂对油气藏的破坏作用,基于油气成藏后断裂再活动对泥岩盖层封闭破坏的研究,通过比较油气成藏后断裂再活动速率与破坏泥岩盖层封闭所需最小活动速率的大小,建立了一套基于地震资料判断油气成藏后断裂再活动是否破坏泥岩盖层封闭的方法,并将其应用于渤海湾盆地辽河西部凹陷齐家—鸳鸯沟地区和冀中坳陷饶阳凹陷留楚地区油气成藏后断裂再活动是否破坏泥岩盖层的研究。结果表明:齐家—鸳鸯沟地区油气成藏后断裂再活动速率小于破坏沙一段泥岩盖层封闭所需的最小活动速率(2 m/Ma)的区域主要分布在其四周;留楚地区油气成藏后断裂再活动速率小于破坏东一段泥岩盖层封闭所需的最小活动速率(4.1 m/Ma)的区域主要分布在留楚塌陷背斜构造的核部和留楚南背斜构造的核部。研究结果与齐家—鸳鸯沟地区沙二段和留楚地区东二、三段目前已发现的油气分布相吻合,表明基于地震资料判断油气成藏后断裂再活动是否破坏泥岩盖层封闭的方法是可行的。

Seismic data was used to investigate the effect of fault reactivation on the sealing of mudstone caprocks of oil and gas reservoirs.This paper proposes a method for determining the impact of fault reactivation on the sealing of mudstone caprock by comparing faults reactivity speeds to the minimum reactivity speed required for breaching the sealing of mudstone caprock after reservoir formation.This method was applied in the Qijia-yuanyanggou region of the West Liaohe sag in the Bohaiwan basin and the Liuchu region of the Raoyang sag in the Jizhong depression.The results indicate that,for the Qijia-yuanyanggou region,the area where the fault reactivity speed was less than the minimum reactivity speed (2 m/Ma) required for breaching the sealing of Es1 mudstone caprock after reservoir formation mainly distributes in the area surrounding Qijia-yuanyanggou region,which is supported by the presence of oil and gas in Es2.For the Liuchu region,the area where the fault reactivity speed was less than the minimum reactivity speed (4.1 m/Ma) required for breaching the sealing of Ed1 mudstone caprock mainly distributes in the middle of collapsed and south anticline in south of Liuchu,which is supported by the presence of oil and gas in Ed2 and Ed3.The proposed method is suitable for the prediction of a sealing of mudstone caprock breach due to fault reactivation after reservoir formation.

国家自然科学基金“油源断裂转换带优势输导油气条件研究”(41372153)资助。