Grey decision-making theory in the optimization of strata series recombination programs of high water-cut oilfields

The development performance of bedded sandstone reservoirs by water drive become worse year by year after entering the high water-cut stage. Optimization and recombination of the strata series based on reservoir subdivision is an effective way to improve water injection effect and to increase producing level. This paper uses the mono-objective grey situation decision-making method, combines various indexes and the expert experiences reflecting reservoir development performance, introduces the concept of effect factors to consider various factors which reflect the contradictories of reservoir strata series, such as permeability differentials, single layer water flooding degree, producing level, remaining amount of resources, hole interval length and the amount of oil layer, to create measurement matrix for comprehensive effects and then to work out the optimal solution of strata recombination programs. Case analysis and comparison with the reservoir numerical simulation result showed that, the grey decision-making optimization method has reliable results, can effectively solve the contradiction between of the efficiency and effect, and can help to guide the development and adjustment of bedded sandstone reservoirs by water drive during the high water-cut stage.

摘要：水驱层状砂岩油藏进入高含水开发期后开发效果逐年变差，在细分层的基础上进行层系优化重组，是改善注水开发效果、提高动用程度的有效手段。利用单目标灰色局势决策方法，将灰色决策理论的思想与反映油藏开发效果的各种指标以及专家经验相结合，并引入效果因子概念，综合考虑反映油藏层系矛盾的各种因素，如渗透率级差、单层水淹程度、动用程度、剩余资源量、井段长度与油层个数等，构造出效果样本矩阵和效果测度矩阵，从而能快速地确定最优层系组合方案。实例分析及与油藏数值模拟结果对比表明，灰色决策优选法结果可靠，能有效解决传统方法效率与效果不能兼顾的矛盾，并有助于指导层状注水砂岩油藏高含水期的开发调整。图2表4参10