复杂小断块油藏氮气吞吐数值模拟

Numerical simulation of nitrogen stimulation for complex small fault-block reservoir

针对江苏陈堡油田陈2西断块的地质条件和开发现状，在压力-体积-温度试验和相态拟合的基础上，应用油藏数值模拟技术，分析产液量、周期注入量、注入速度、焖井时间和吞吐周期对吞吐效果的影响。结果表明：产液速度和周期注入量对氮气吞吐效果的影响较大，并存在最佳的产液速度和周期注入量；氮气吞吐增油量和换油率第1周期最高，第3周期以后换油率明显下降，氮气吞吐以2—3个周期为宜；在地层条件和设备允许的情况下，增加注入速度有利于提高油井产量。

According to the geologic conditions and present development conditions of the west Chen 2 fault block in Jiangsu Chenbao Oilfield, the influences of five sensitivity factors including liquid-producing capacity, cyclic nitrogen injection volume, injection rate, soaking time and stimulation cycle on the nitrogen stimulation effect were analyzed by numerical simulation based on the pressure-volume-temperature experiments and phase behavior matching. The results show that the liquidproducing capacity and cyclic nitrogen injection volume have a great effect on nitrogen stimulation effect, and there are optimal values respectively. Higher values of extra oil production and oil exchange ratio are obtained in the first stimulation cycle, and the oil exchange ratio descreases in the third cycle, so the optimal stimulation time is 2 to 3 cycles. The oil production could be enhanced by increasing injection rate if the formation and equipment conditions enabled.