泥岩盖层内断裂垂向封闭油气能力综合评价方法

Comprehensive evaluation of fault vertical sealing ability with mudstone caprocks

泥岩盖层内断裂垂向封闭油气能力主要受断层岩排替压力、泥岩盖层断接厚度和下伏储层油气剩余压力的影响,断层岩排替压力越大、泥岩盖层断接厚度越大、下伏储层油气剩余压力越小,泥岩盖层内断裂垂向封闭油气能力越强;反之则越弱。通过确定断层岩排替压力、泥岩盖层断接厚度和下伏储层剩余压力,根据油气在下伏储层剩余压力的作用下通过泥岩盖层内断裂渗滤、散失速度的相对大小,建立了一套泥岩盖层内断裂垂向封闭油气能力的综合评价方法。对海拉尔盆地贝尔凹陷呼和诺仁构造的断裂垂向封闭油气能力综合评价结果表明:油气在剩余压力作用下通过14个测点处大一段泥岩盖层内断裂F1渗滤、散失速度均小于0,表明大一段泥岩盖层内断裂F1垂向封闭油气能力均相对较强,有利于油气在南二段聚集与保存,与目前断裂F1附近南二段已发现大量油气分布相吻合,说明文中方法适用于综合评价泥岩盖层内断裂垂向封闭油气能力。

The fault vertical sealing hydrocarbon ability with mudstone caprocks is mainly influenced by the displacement pressure of fault rocks,the caprockfault juxtaposition thickness,and the hydrocarbon residual pressure in underlying reservoirs.The greater of displacement pressure of fault rocks,the thicker of caprock-fault juxtaposition thickness,and the smaller of hydrocarbon residual pressure in underlying reservoirs,the stronger of fault vertical sealing hydrocarbon ability with mudstone caprocks,and vice versa.A comprehensive evaluation of fault vertical sealing hydrocarbon ability with mudstone caprocks is proposed in the paper based on the displacement pressure of fault rock,the caprock-fault juxtaposition thickness,the hydrocarbon residual pressure in underlying reservoirs,and hydrocarbon permeation and dissipation velocity within mudstone caprocks.The proposed comprehensive evaluation is applied to the structures of Huhe and Nuoren in Hailar Basin.The permeation and dissipation velocity at 14 measuring points within mudstone caprocks are less than 0,which indicates that the vertical sealing hydrocarbon ability is relatively strong and it is conducive to the hydrocarbon accumulation.These evaluation results are coincident with the hydrocarbon discovery in the area and prove the validity of the proposed approach.