油藏特高含水期井网加密潜力评价新方法

针对以往井网加密潜力评价方法在油藏特高含水期应用中存在的不适应性,以胜利油区40个开发后期中高渗透水驱砂岩油藏单元为样本,建立了井网密度与加密井平均单井增加可采储量的关系,并对其影响因素进行了分析.结果表明,加密井平均单井增加可采储量与井网密度呈指数关系,并且随着井网密度的增大,加密井平均单井增加可采储量逐渐减小；但加密井平均单井增加可采储量与井网密度关系曲线的形态各不相同,其主要影响因素是流动系数、储层非均质性以及开发过程中地层能量的保持状况.基于单井经济极限可采储量的理论计算公式,计算得到中高渗透砂岩油藏在不同油价、不同井深条件下的单井经济极限可采储量计算图版,依据该图版和所建立的井网密度与加密井平均单井增加可采储量的关系,可对特高含水期油藏井网加密潜力进行评价.实例应用结果表明,胜坨油田二区沙二段83-5单元在油价为80美元/bbl时,单井经济极限可采储量为0.57×104 t,经济极限井网密度为20口/km2.

New methods of potential evaluation of well pattern infilling during extra-high water cut stage

In response to the unsuitability of infilling potential evaluation method in an extra-high water cut stage in field, we analyze the oil field development process on the basis of the variation of the well network density conditions and infilling development effect.Based on the research, we establish the rule of well spacing density for infill wells to increase recoverable reserves, and combined with the economic limit of single well recoverable reserves in different prices, we propose a new infill potential evaluation method. The infilling method for extra-high water cut stage oilfield has better adaptability, and is able to guide the infilling potential evaluation for oilfield at extra-high water cut stage.