基于指标特征模型的油藏注水开发效果定量化评价

Quantitative evaluation of reservoir water-flooding development effect based on index characteristic model

从油田注水开发相关技术标准和规范中筛选确定了水质达标率、注采比、分注率、自然递减等30项评价指标,来表征注水工作在油藏、工艺、地面系统和管理业务的系统性特点。提出了评价指标特征数值模型的概念,将每一项评价指标的理论规律、统计规律和技术要求等描述转换为对指标特征的数值描述,3个特征要素为指标值域范围、变化规律和评价结果分级区间定义。按复杂断块、中高渗透砂岩、低渗透砂岩和碳酸盐岩油藏类型分别建立各项指标在低含水、中含水、高含水和特高含水阶段的特征模型。不同类型油藏在不同含水阶段的各项评价指标的特征数值模型以分级雷达图形式展现为评价图版。建立每项指标分值计算规则,计算评价指标实际数值所对应的分值,汇总得到油藏总的得分,根据连续时间的得分变化反映油藏注水效果的变化,实现油藏注水开发效果的定量化评价。应用该方法开发了大港油田注水开发定量化评价软件,可分析注水指标技术状况和运行趋势。

A total of 30 evaluation indices, including water quality compliance rate, injection production ratio, separate injection rate and natural decline rate, were selected and determined from related technical standards and norms of oilfield water-flooding develop- ment. These indices were used to characterize the systemic characteristics of water-flooding in reservoir, processing, ground system and management business. The concept about the numerical model of evaluation index characteristics was proposed to convert the theoretical laws, statistical rules and technical requirements of each evaluation index to the numerical description of index characteristics. Three characteristic elements included the index domain range, variation law and gradation interval definition of evaluation re- sult. According to the reservoir types of complex fault block, mid-high-permeability sandstone, low-permeability sandstone and carbonate reservoir, the characteristic model of each index was established in low water cut, middle water cut, high water cut and ultra- high water cut stages, respectively. For different reservoir types in different water cut stages, the characteristic numerical model of each evaluation index and gradational radar chart were presented as evaluation charts. The score calculation rule of each index was established to calculate the corresponding scores of the actual numerical evaluation index and summarized the total score of reservoir. The score changes in continuous time can reflect the changes in reservoir water-flooding effect, so as to achieve the quantitative eval- uation on the effect of reservoir water-flooding development. By this method, the quantitative evaluation software of water-flooding development in Dagang oilfield was developed to analyze the technical state and operation trend of water-flooding indices.