海上油田二元复合驱后弱凝胶调驱可行性分析

为解决海上油田二元复合驱后,部分油组层间矛盾加剧,注入流体多沿高渗条带及大孔道突进的问题,通过对渤海JZ油田储层非均质性、温压系统、边水能量、地层水矿化度等因素的分析以及三管并联模型开展系列物理模拟实验,研究了海上油田二元复合驱后弱凝胶调驱可行性。结果表明,弱凝胶体系先进入渗流阻力较小的高渗层,增加其渗流阻力,使得注入压力增加,中、低渗层吸液压差随之增加,吸液量增加,且注入水转向进入中、低渗透层,使其剩余油饱和度降低,动用程度增加,弱凝胶调驱阶段采出程度为17.81%,最终采收率值为71.62%。可见,弱凝胶调驱可作为海上油田二元复合驱后提高采收率的方法。

Feasibility Analysis of Weak Gel Flooding in Offshore Oilfield after Binary Composite Flooding

In order to solve the problem of intensified interlayer contradiction and the inrush of injected fluid along high permeability zones and large pore channels in offshore oilfields after binary compound flooding, a series of physical simulation experiments were carried out through the analysis of reservoir heterogeneity, temperature and pressure system, edge water energy, formation water salinity and three-pipe parallel model in Bohai JZ oilfield. The feasibility of weak gel flooding in offshore oilfield after two element composite flooding was studied. The results showed that the weak gel system first entered the high permeability layer with less seepage resistance, increased its seepage resistance, increased the injection pressure, increased the suction pressure difference in the middle and low permeable layers, increased the liquid absorption, and injected water into the middle and low permeable layers, resulting in the decrease of the remaining oil saturation, the increase of the utilization degree, and the weak gel flooding. The stage recovery rate is 17.81%, and the final recovery rate is 71.62%. It can be seen that weak gel flooding can be used as an enhanced oil recovery method after two element composite flooding in offshore oilfield.