黄河口凹陷沙三中段储层水淹定量评价

Quantitative evaluation of water flooding in E_(2)s^(3M) of Huanghekou Sag

综合应用黄河口凹陷B油田沙三中段测井、分析化验和开发动态资料,根据熵的原理提出一套利用熵权定量表征水淹非均质性的方法,阐明了水淹非均质性的控制因素及剩余油的分布规律。研究表明:研究区层间非均质性较弱而层内非均质性较强,地层系数、渗透率突进系数和距断层距离是影响水淹非均质的主要因素,孔隙度、渗透率和泥质含量影响较小;根据水淹指数可将水淹层定量划分为四个级别:未水淹(If_(w)≥0.80)、弱水淹(0.74≤If_(w)<0.80)、中水淹(0.65≤If_(w)<0.74)和强水淹(If_(w)<0.65)。研究区剩余油呈现两种分布样式,即边缘断控型和孤立型,以边缘断控型为主。根据研究区研究结果,在位于断层附近构造高部位的水淹指数高值区部署了调整井,该井实际生产情况与水淹非均质性研究成果一致。研究成果对类似油田水淹非均质及剩余油预测研究具有较好的借鉴作用。

Based on the comprehensive application of logging,analytical test,and dynamics in E_(2)s^(3M) of Huanghekou Sag,according to the entropy principle,it is proposed a method of quantitative characterization of waterflooding heterogeneity using entropy weight.And then the controlling factors of water flooding heterogeneity and the distribution law of remaining oil are clarified.The results show that the inter-stratum heterogeneity is weak while the infra-stratum heterogeneity is strong,the stratigraphic coefficient,the permeability protrusion coefficient,and the distance from the fault are the main factors affecting the water flooding heterogeneity,while the porosity,permeability,and shale content are less affected.The water flooded formations can be quantitatively classified into four classes according to the water flooded index:unflooded(If_(w)≥0.80),weakly waterflooded(0.74≤If_(w)<0.80),moderately waterflooded(0.65≤If_(w)<0.74)and strongly waterflooded(If_(w)<0.65).The remaining oil in the study area shows two distribution styles,namely,marginal break-control type and isolated type,with marginal break-control type predominant.According to the research results of the study area,adjustment wells were deployed in the area with a high value of water flooding index located in the high part of the structure near the fault,and the actual production of this well is consistent with the research results of water flooding heterogeneity.The results of the study are useful for the research on water flooding heterogeneity and remaining oil prediction in similar oilfields.