欢喜岭油田欢50块高温油藏提高采收率方法研究

EOR METHOD APPLIED IN HUAN50 RESERVOIR WITH HIGH TEMPERATURE, HUANXILING OILFIELD

欢喜岭油田欢５０块高温油藏室内提高原油采收率实验结果证明：欢５０块原油／（碱十表面活性剂）体系的界面张力随温度的升高而降低。可利用界面张力与温度关系曲线外推，获得不易测定的较高温度下的界面张力值。由于欢５０块油藏温度很高，表面活性剂的热稳定性成为化学驱成功与否的关键。试验证明，含盐度是影响表面活性剂热稳定性的主要因素之一。配方１．５％Ｎａ２ＣＯ３＋０．４％ＬＨ，可满足高温条件下欢５０块油藏原油低张力驱替的要求。室内岩心驱油效率试验的结果表明：碱／表面活性剂驱不但能较大幅度地提高采收率，而且可以增大油藏中的渗滤速度，降低注入压力，从而减小渗透率较低油藏的高压注水难度，节省开采费用。

Enhanced oil recovery in Huan50 reservoir with high temperature, Huanxiling oilfield by chemical flooding was studied in laboratory. The result of experiments showed: the interfacial tension (IFT) between alkaline+surfactant solution/Huan50 oil decreased with the increase of temperature, and the value of IFT being difficult to measure in higher temperature could be obtained through extrapolation of IFT as function of temperature. because the temperature in Huan50 reservoir is very high, thethermal stability of surfactants becomes a key point for the success of chemical flooding, and it was proved that salinity is oneof very important factors to affect the thermal stability of surfactants. The flooding of ultralow IFT in Huan50 reservoir in high temperature could be reached with formula: 1. 5 % Na2CO3+ 0. 4 % LH (surfactant ). The tests of core flood in laboratory indicated that not only oil recovery could be greatly enhanced but also the velocity of filtration in reservoir increased with alkaline/surfactant flooding, so that high pressure injection in low permeability reservoir became less difficult for the decrease of injection pressure.