安塞油田特低渗透油藏有效驱替压力系统研究及注水开发调整技术

安塞油田特低渗透油藏的非均质性较强，注水开发启动压力梯度大，天然微裂缝较发育和油井见水后采液，采油指数下降等因素对注水开发效果的影响日益突出，应用压力叠加原理研究地层压力分布规律，计算注采井间压力及压力梯度分布曲线，结合室内试验及现场测试确定的启动压力梯度值，确定建立有效驱替压力系统的合理排距，开展以强化注水、不稳定注水、沿裂缝线状注水、注水产液剖面调整为主的注采调整以及裂缝侧向加密调整，取得了明显稳产效果。

The effective driving pressure system study and adjustment techniques of waterflooding in Ansai oil field

The effects of many factors on waterflooding in Ansai extra low permeability oil field, such as the stronger heterogeneity of reservoirs, the bigger starting pressure difference and driving pressure gradient, the natural fracture development and the declining productivity index after water breakthrough are getting increasingly strong. On the basis of Pressure Superposition Principle, the formation pressure distribution, the pressure difference and pressure gradient between producers and injectors were established, and the reasonable well array spacing and the effective driving pressure system were determined by using the start up pressures gained from laboratory experiment and on site measurement. These methods, combined with some other adjusting techniques of waterflooding, such as forced waterflooding, non steady waterflooding, line waterflooding along the fracture, adjusting injection and production profile and infill drilling along the fracture, have provided good result in stabilization of oil production.