低渗砂岩油藏优势注采方向量化表征技术及应用

Quantitative Characterization Technology and Application of Dominant Injection-Production Direction in Low-permeability Sandstone Reservoirs

对于储层物性差、非均质性强的低渗砂岩油藏,开发进入中高含水期后,在优势注采方向易形成注水无效循环,注水利用率低,开发效果差。为此,以井组为单元,依据渗流力学水电相似原理,结合开发过程中的动态监测资料,建立注水量在纵向及平面上的劈分权重计算方法,采用注采方向单位油层厚度累计吸水量、注采方向累计吸水比和注采方向吸水孔隙体积倍数3个参数进行约束,确定优势注采方向在平面上的量化表征参数及其判别标准。实例应用表明:优势注采方向量化表征技术在特高含水阶段精细注水调控方面具有重要作用,注水调控177井次,优势注采方向注水量减少3115 m^(3)/d,弱吸水方向注水量增加5376 m^(3)/d,无效注水比例由20%左右降至10%以内。该研究对同类型油藏精细注水调控及剩余油挖潜具有指导意义。

For low-permeability sandstone reservoirs with poor reservoir physical properties and strong heterogeneity,it is easy to form ineffective water injection cycle in the dominant injection-production direction in the moderate and high water-cut stages,resulting in low utilization of injected water and poor development effect.Therefore,based on the similar principle of seepage mechanics and hydroelectricity of the well group and the dynamic monitoring data acquired in the development process,a weighted calculation method was established to split the water injection rate in the longitudinal and planar directions.Three parameters,cumulative water intake rate per unit oil layer thickness in the injection-production direction,cumulative water intake ratio in the injection-production direction and water intake volume in the injection-production direction,were constrained to determine the quantitative characterization parameters on the plane in the dominant injection-production direction and their differentiation standard.The application proved that the quantitative characterization technology of the dominant injection-production direction had significant effect the fine water injection control in the ultra-high water-cut stage.After the water injection control of 177 wells,the water injection rate was reduced by 3115 m^(3)/d in the dominant injection-production direction and increased by 5376 m^(3)/d in the low water absorption direction,and the proportion of ineffective water injection decreased from about 20%to less than 10%.This study plays a guiding role in fine water injection control and remaining oil exploitation in the same reservoir.