歧口18-1 油田晚期注水研究

在边水能量微弱的天然条件下，歧口18-1 油田投产后衰竭开采7.5 a，导致地层压力由30.5 MPa下降到注水前的14.8 MPa，远低于28.9 MPa 的原油饱和压力。地层压力大幅度下降对油气储层及流体产生了一定的伤害，使流体脱气形成油、气、水三相流动，大大降低了原油相对渗透率，从而降低原油产量。根据室内岩心实验结果，并类比国内外相似油田开发经验，运用物质平衡及油藏数值模拟方法进行研究，结果表明，在注水初期以不低于6 的日注采比注水，既能使地层压力得到一定恢复，又能使晚期注水仍取得较好的开发效果。

Study on late water flooding in Qikou 18-1 Field

With insufficient edge water energy, Qikou 18-1 Field has produced for 7.5 years. The reservoir pressure decreased from 30.5 MPa to 14.8 MPa, far lower than the crude oil saturation pressure of 28.9 MPa. The precipitous decline of reservoir pressure leads to oil-gas-water three-phase flow and reduce the relative permeability of crude oil, which makes the crude production decreased. Based on the laboratory test, material balance method and numerical reservoir simulation are used to carry out the study. The result shows that reservoir pressure can build up to a certain extent with a rightful injection-production ratio in the initial water injection.