利用压汞实验确定岩心麻皮系数 —以鸭儿峡油田白垩系为例

为了分析麻皮效应对鸭儿峡油田白垩系砂砾岩油藏取心分析含油饱和度的影响,综合运用压汞资料、分析化验资料和生产资料,利用岩石物理模型和取心样品对压汞法产生麻皮效应的机理进行系统分析;通过构建J函数,计算油藏的平均毛管压力,并对毛管压力曲线的4个切点开展系统论述;分析油藏排驱压力、不同类型孔喉的进汞饱和度、麻皮效应影响区间和麻皮系数。依据麻皮系数,对岩心含油饱和度进行校正;对校正前后的饱和度参数与阿尔奇公式计算的理论值以及生产资料分别进行对比。结果表明,经麻皮系数校正后的岩心测量含油饱和度较岩心视含油饱和度低15%左右,与测井计算的饱和度和生产资料吻合较好。研究结果一定程度上可为研究区岩心基础资料研究提供技术参考,为油藏饱和度评价及资源量计算提供可靠数据。

Core uneven coefficient processing based on mercury injection experiment: a case of Cretaceous glutenite reservoir in Yaerxia Oilfield

In order to analyze the effect of uneven skin effect on oil saturation of Cretaceous sandy conglomerate reservoir coring analysis in Yaerxia Oilfield, the mechanism of uneven skin effect produced by core mercury injection method in the study area was explained in detail by using rock physical model and coring samples, using mercury injection data, analysis of laboratory data and production data. The mechanism of uneven skin effect produced by mercury injection method is systematically analyzed; the average capillary pressure curve of reservoir is calculated by constructing "J" function curve, and four tangent points of capillary pressure curve are systematically discussed; the displacement pressure of reservoir and mercury saturation of different pore throats are analyzed, and Yaerxia Oilfield is obtained. The influence interval and uneven coefficient of core uneven effect in Cretaceous glutenite reservoir. According to the flax skin coefficient, the oil saturation of the core is corrected, and the saturation parameters before and after the correction are compared with the theoretical values calculated by Archie formula and the production data. The results show that the oil saturation measured by cores corrected by uneven skin coefficient is about 15% lower than the apparent oil saturation of cores, which is in good agreement with the saturation calculated by well logging and production data. To a certain extent, the research results provide technical reference for the study of core basic data in the study area, and provide reliable data for reservoir saturation evaluation and resource calculation.