特高含水期油田注水层段划分新方法

A New Method for Dividing Water Injection Strata at Ultra-high Water-cut Stage of Oilfield

多层砂岩油田进入特高含水期后,小层渗流能力大小受动静态因素共同决定,将渗透率作为注水层段划分的主要指标,已不能达到层段内注水均匀推进的目的。以油水两相流达西公式为基础,分析了油水井间渗流阻力大小的影响因素,依据水电相似原理对各小层的渗流阻力进行了定量计算,以目前分层工艺限制作为约束条件,以单井平均层段渗流阻力变异系数最小化为目标,提出了水井层段调整的具体步骤。应用该方法对Z区块10口水井进行了层段调整,在油井综合含水率超过96%的情况下,单井初期日增油0.2t。按照渗流阻力进行注水层段组合的新方法,为特高含水期油田缓解层间矛盾提供了新的思路。

After multilayer sandstone oilfields enter the extremely high water cut stage, the small layer seepage ability is decided by the dynamic and static factors together. Taking permeability as the main index of dividing inj ection strata can not achieve the goal of uniform water inj ection. On the basis of Darcy formula, the factors influencing the seepage resistance between oil and water wells are analyzed for calculating the seepage resistance of each sublayer quantitatively according to the principle of hydroelectricity similarity. By taking layering injection process as the constraint and minimizing average variation coefficient of seepage resistance of strata as the target, the concrete steps for the adjustment of strata are put forward. This method is used to adjust 10 wells in Z Block. Although the average water cut of oil well exceeds 96%, single well daily increasing oil reaches 0. 2t. This method provides a new idea for alleviating the contradiction between layers at the extremely high water-cut stage.