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简要介绍了断层封闭性研究现状和主要研究方法 ,阐述了油田现今地应力作用方向、大小对断层封闭性的影响 ,即在某一应力大小的条件下 ,现今水平主压应力方向与断层走向的交角越大 ,断层封堵油气的可能性越大 ,反之则越小 ;在某一断层产状条件下 ,作用于断层面的联合压应力大于或等于岩石抗压强度 ,有利于增强断层封闭作用 ,反之不利于断层封闭。以辽河坳陷西部凹陷笔架岭油田为例 ,选取该地区 4口井4 6个层段 ,计算了钻孔井壁崩落的优选方位及相应的现今最大水平主压应力作用方向 ,分析认为最大水平主压应力方向总体为北西向 ,与主干断层走向呈大角度相交或近于垂直 ,据此评价 4条主干断层总体上对油气的封闭性在沙河街组一段和东营组三段好 ,向浅部变差。采用声发射法测量了该区 10口井 4个层位现今最大水平主压应力数值和岩石抗压强度 ,据计算所得联合压应力评价了其中 3条主干断层的封闭性 ,总的变化趋势是深部好而浅部差。笔架岭油田的油气藏实际分布证实了评价结果是可靠的 ,这对于该区井位选择、区块评价、储量计算及制订正确开发方案有极重要的地质意义和现实意义
The research status and main research methods of fault sealing are briefly introduced. The effect of current direction and magnitude of the earth stress on the sealing of the fault is expounded. Under the condition of a certain stress, the current horizontal principal compressive stress direction and fault strike The larger the angle of intersection is, the more the possibility of fault sealing oil and gas is, and vice versa. The joint compressive stress acting on the fault plane is greater than or equal to the compressive strength of the rock under a fault-shaped condition, which is beneficial to enhance the fault sealing , On the contrary not conducive to fault closure. Taking the Bijiaoling Oilfield in the western depression of Liaohe Depression as an example, 46 wells of 4 wells in this area were selected to calculate the optimal orientation of the borehole wall caving and the corresponding action direction of the present maximum horizontal compressive stress. It is considered that the maximum level The direction of principal compressive stress is generally northwesterly and intersects with or is nearly perpendicular to the main fault. According to the above, the main seal faults of the four main faults are well sealed to the oil and gas in the first and the third sections of Shahejie Formation and the shallow Ministry worsened. Acoustic emission method was used to measure the present maximum horizontal compressive stress values and compressive strength of the four reservoirs in 10 wells in this area. According to the calculated compressive stress, the sealing of 3 main faults was evaluated, and the general trend was Deep good and shallow poor. The actual distribution of the BijiaLing oil and gas reservoir confirms that the evaluation result is reliable, which is of great geological significance and practical significance for the selection of well location, block evaluation, reserves calculation and formulating the correct development plan for this area