北部湾盆地涠西南凹陷W油田储层综合评价研究

Comprehensive evaluation of reservoirs in W oilfield in the southwest depression of Beibu Gulf Basin

北部湾盆地涠西南凹陷W油田主力产油层段为古近系流沙港组流一段,其储层分布复杂,砂体连通性和有利甜点区不清,储层非均质性强,导致油田开发效果差。为明确油田流一段储层展布特征和砂体连通性情况,寻找储层有利挖潜区域,指导后续生产调整挖潜与优化,本文依据岩芯和测井资料,从沉积相、储层物性和非均质特征等方面,研究表征了W油田流一段储层特征;选择全面反映储层特征的砂岩厚度、有效砂体厚度、沉积微相、孔隙度、变异系数、渗透率和夹层密度7个因子作为评价参数,采用灰色关联分析法确定权系数,建立储层综合评价分类体系,最后用储层评价方法对储层进行综合评价打分,厘清了有利储层分布,并创新应用多参数叠合优势区域对比法对评价结果进行验证。依据综合评价方法,对油田2个主力油层综合指数进行打分,根据综合评价得分、储层参数和实际生产情况,将储层分为3类,每类对应的分值区间分别为Ⅰ类大于40,Ⅱ类20~40,Ⅲ类小于20。其中,L1中-Ⅲ-1小层储层较好,Ⅰ类储层发育范围大;在L1中-Ⅲ-2小层南东面发现一无井控的Ⅰ类有利储层区域,后期调整部署一采一注井网,调整井实施后,储量规模和含油性得到落实,井网注采开采效果好,提高了油田经济效益。本次储层综合评价方法和评价结果结合多参数叠合优势储层对比验证的方法,使有利区域范围更精确,评价结果可信度更高。

The main oil producing zone of W oilfield in Weixinan sag of Beibu Gulf Basin is the first member of Paleogene Liushagang Formation. Its reservoir distribution is complicated, sand body connectivity and favorable sweet spot are not clear,and reservoir heterogeneity is strong, resulting in poor oilfield development effect. In order to clarify the characteristics of reservoir distribution and sand body connectivity in the first member of the current formation of the oilfield, to find the favorable potential areas of the reservoir, and to guide the subsequent production adjustment and optimization of the potential. Based on the core and logging data, this paper studies and characterizing the reservoir characteristics of the first member of the oilfield flow from the aspects of sedimentary facies, reservoir physical properties and heterogeneity. Choose to fully reflect the characteristics of the reservoir sandstone thickness, effective thickness of sand body and sedimentary microfacies, porosity, density of interlayer and permeability variation coefficient, seven factors as evaluation parameters, the grey correlation analysis method to determine the weight coefficient, set up comprehensive evaluation of reservoir classification system, and finally with reservoir evaluation method for comprehensive evaluation of reservoir, to clarify the distribution of favorable reservoir, The evaluation results are verified by using the multi-parameter superposition advantage region comparison method. According to the comprehensive evaluation method, the comprehensive index of the two main oil reservoirs is scored. According to the comprehensive evaluation score, reservoir parameters and actual production, the reservoirs are divided into three categories. The corresponding score interval of each category is more than 40 for type Ⅰ, 20~40 for type Ⅱ and less than 20 for type Ⅲ. The L1 medium to Ⅲ-1 small reservoirs are better, and the Ⅰ type reservoirs have a large development range. A class Ⅰ favorable reservoir area without well control was found in the south and east of the L1 medium-Ⅲ-2 stratum. After adjusting and deploying one production and one injection well pattern, the reserve scale and oil content were implemented. After implementing the adjustment well pattern, the injection, production and production effect of the well pattern were good, which improved the economic benefits of the oilfield and helped the oilfield to increase production and reservoir. The comprehensive reservoir evaluation method and evaluation results combined with the method of multi-parameter superposition and comparative verification of dominant reservoirs make the range of favorable areas more accurate and the evaluation results more reliable.