基于岩石物理相的水淹层综合评价方法研究

Study on comprehensive evaluation method of water-flooded zone based on petrophysical facies

南苏丹P油田是Melut盆地勘探开发较早的区块,开发中后期由于底水锥进、边水推进和注入水水淹,目前已进入中高含水期阶段。针对储层非均质性强、含泥较重的特征,基于流动单元指数理论以及压汞和物性实验数据,采用累积频率法将储层划分为3种岩石物理相。通过敏感性测井、录井响应,优选了自然电位、电阻率、气测等曲线,对水淹层进行综合定性识别;基于岩石物理相的划分结果,对不同储层类型的原始含水饱和度、剩余油饱和度、束缚水饱和度等参数进行精细评价,进而精确确定含水率参数,实现了水淹层精细定量评价。该方法应用于实际生产的结果表明,水淹层识别准确率达到90.9%,水淹层定量评价结果与生产实际结果相符,满足了油田开发生产对水淹层评价的需求。

P Oilfield in South Sudan is an earlier exploration and development block in Melut Basin.Due to bottom water coning,edge water incursion and injection water flooding in medium and late development phases,it has entered the medium-high water cut stage.For strong reservoir heterogeneity and heavy mud,the reservoir is divided into three petrophysical facies by cumulative frequency method based on the flow unit index theory,mercury injection and physical property experimental data.Through sensitivity logging and mud logging responses,optimize natural potential,resistivity,gas logging and other curves to comprehensively and qualitatively identify the water-flooded zones.Based on the division results of petrophysical facies,the original water saturation,remaining oil saturation,irreducible water saturation and other parameters of different reservoir types are finely evaluated.Then the water cut is determined precisely,and the fine quantitative evaluation of water-flooded zone is realized.The method is applied to production practice.The results show that the identification accuracy of water-flooded zone is 90.9%,and the quantitative evaluation results of water-flooded zone are consistent with the actual production results,which meets the needs of oilfield development and production for water-flooded zone evaluation.