大港油田枣35区块裂缝性火山岩稠油油藏注水开发特征及效果评价

Waterflooding characteristic and effect evaluation of the fractured volcanic heavy oil reservoir of block Zao35.

针对大港油田枣35区块裂缝性火山岩油藏的裂缝分布特征和流体特征,应用油藏工程方法对注水开发后的动态资料进行了详细分析,该油藏注水开发后地层压力急剧下降的趋势得到控制,并开始缓慢回升,但产量递减幅度仍然较大。分析表明,注入水沿裂缝窜流,导致采油井暴性水淹,油藏整体含水上升幅度大,注水15个月就进入高含水阶段;注入水的无效循环,导致存水率、水驱指数和体积波及系数都很低,注入1×104m3水只能采出0.22×104t油;目前该油藏采出程度为4.06％,水驱采收率小于6％,油藏水驱剩余可采储量低,但实际剩余储量高,水驱条件下油层潜力得不到充分发挥。应采用其他开采方式以进一步提高该油藏的剩余资源利用程度。

According to the characteristics of fracture distribution and fluid in the fractured volcanic oil reservoir of block Zao35, dynamic data after water flooding were analyzed in detail using reservoir engineering method. After waterflood development in this oil reservoir, the trend of sudden drop in formation pressure was controlled and began to rise slowly,but the decline rate of the oil production was still very high. The injected water channeled rapidly along the natural fracture of this reservoir , and most of the oil production wells were flooded severely. The water cut of this reservoir went up integrally and rapidly,and only after 15 months of waterinjection it entered high-water-cut period. Invalid cycle of the injected water made water-restrained rate, waterflooding index and volumetric sweep efficiency were very low. Water injection of 1×10 m can only produce 0. 22×104t equivalent oil. At present recovery percent of reserves is 4.06% , and the terminal recovery efficiency of water-flooding is less than 6%. Remaining recoverable reserve of the water-flooding reservoir was low, but the actual remaining recoverable reserve was high,so the potential of the oil reservoir can not be tapped efficiently.Other production way should be adopted to improve the usage degree of the remaining resources in this oil reservoir.