近油源低渗透砂岩地层水特征及饱和度解释——以东营凹陷南斜坡沙河街组为例

发布时间：2018-02-21 00:20

  本文关键词： 低渗透砂岩 地层水电阻率 饱和度 测井解释 离子色谱　出处：《中国矿业大学学报》2017年06期 　论文类型：期刊论文

【摘要】：提出近油源低渗透砂岩油藏中的油层和水层地层水电阻率(Rw)选值及饱和度计算方法.选取东营凹陷南斜坡沙河街组沙三段(ES3)、沙四段(ES4)不同含油级别岩样,利用离子色谱技术对其进行氯盐含量测试,发现不同含油级别样品氯离子质量浓度存在明显的差异,进一步将氯离子质量浓度折算成矿化度,明确了油层、水层地层水矿化度取值规律及差异成因.研究结果表明:东营凹陷南坡沙河街组低渗透砂岩油藏中油层地层水矿化度约是水层的1.2~1.7倍,从油气成藏角度分析认为,油层地层水主要为伴随烃运聚的高矿化度水赋存于岩石微孔隙中,且与水层或围岩隔离,不宜扩散交换,得以保持成藏流体高矿化度特征(平均大于30g/L),而水层中基本保留了原始沉积的低矿化度水,导致即使同一套油水系统中,油、水层具有不同的矿化度,这一认识对近油源的低渗透砂岩油藏应当具有普遍意义.进而在反算典型水层地层水电阻率的基础上,利用实验获得的水层和油层地层水电阻率比例(水层R_w≈1.45×油层R_w),优化了油层R_w选值方法,为有效提高研究区低渗透砂岩油藏的饱和度解释精度提供了依据.
[Abstract]:This paper puts forward a method of selecting formation water resistivity and saturation of reservoir and water layer in low permeability sandstone reservoir near oil source. The rock samples with different oil-bearing grades are selected from Shahejie formation, Shahejie formation, South Slope, Dongying Sag, with different grades of rock samples. It was found that there were obvious differences in chlorine ion concentration in different oil grade samples by ion chromatography, and the chlorine ion mass concentration was further converted into mineralization, and the oil layer was defined. The study results show that the formation water mineralization degree of the low permeability sandstone reservoir in Nanpo Shahejie formation in Dongying depression is about 1.2or 1.7 times that of the water reservoir, and it is considered from the perspective of oil and gas accumulation that the formation water mineralization degree of formation water is about 1.2or 1.7 times that of the water reservoir. Reservoir formation water mainly occurs in rock micropores with hydrocarbon migration and accumulation, and is isolated from water layer or surrounding rock, so it is not suitable for diffusion and exchange. It is possible to maintain the characteristics of high salinity of pool-forming fluids (with an average of more than 30 g / L ~ (-1)), while the low salinity water deposited in the water layer is basically retained, resulting in different salinity of the oil and water layers even in the same oil-water system. This understanding should be of universal significance to low permeability sandstone reservoirs near oil sources. Further, on the basis of inverse calculation of formation water resistivity of typical water layers, Using the ratio of water layer and formation water resistivity (RW 鈮，

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