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注水作为一种提高原油采收率的有效手段已被世界上许多油田所采用,但注水驱油效果的好坏在很大程度上取决于人们对注水动态的监控程度。本文借助于Gassmann方程就薄互层油藏注水地震监测的可能性进行了正演模拟分析,结果表明:砂岩孔隙率是决定注水地震监测成败的关键,砂岩孔隙率越高,越有利于注水地震监测的实施。对于不同的砂泥岩互层模型,只要砂岩孔隙率足够大,且砂岩总厚度足够大,利用地震方法进行注水动态监测是可行的。从地震响应结果发现,当孔隙率固定时,注水会引起反射同根轴的抬升,抬升幅度只与互层内砂岩总厚度有关,与互层总厚度无关,且注水砂岩总厚度越大,反射同根轴抬升越高,同时出现振幅异常。因此,其正演结果既可确定注水波及范围,又可定性或定量判定注水前缘位置及推进方向、推进速度等。
Water injection as an effective means to improve oil recovery has been adopted by many oil fields in the world. However, the effect of water flooding depends largely on the degree of monitoring of water flooding. In this paper, the Gassmann equation is used to simulate the possibility of waterflooding seismic monitoring of thin interbedded reservoirs. The results show that the porosity of sandstone is the key to the success or failure of waterflooding seismic monitoring. The higher the porosity of sandstone, the more favorable the waterflooding earthquake Monitoring implementation. For different sand-shale interbedded models, as long as the sandstone porosity is large enough and the total thickness of the sandstone is large enough, dynamic monitoring of waterflooding using the seismic method is feasible. From the seismic response results, it is found that when the porosity is constant, the water injection will cause the reflection of the same shaft uplifted, and the magnitude of the lift is only related to the total thickness of the sandstone in the interbed, not to the total thickness of the interbed. The higher the shaft lift, at the same time there is an anomaly in amplitude. Therefore, the forward result can not only determine the range of water injection, but also qualitatively or quantitatively determine the position and direction of water injection, propulsion speed and so on.