西南石油大学学报(自然科学版)

• 石油与天然气工程 • 上一篇    下一篇

致密砂岩储层饱和度指数n 计算方法研究

罗少成1,成志刚1,周金昱2,席辉1,王长胜2   

  1. 1. 中国石油集团测井有限公司油气评价中心,陕西西安710077
    2. 中国石油长庆油田分公司勘探开发研究院,陕西西安710018
  • 出版日期:2014-08-01 发布日期:2014-08-01
  • 基金资助:

    中国石油天然气股份有限公司重大科技专项(2011E–2602)。

Research on Saturation Index n of Tight Sandstone Reservoir

Luo Shaocheng1, Cheng Zhigang1, Zhou Jinyu2, Xi Hui1, Wang Changsheng2   

  1. 1. Reservoirs Evaluation Center,China Petroleum Logging Co. Ltd.,Xi′ an,Shaanxi 710077,China
    2. Exploration and Development Institute of PetroChina Changqing Oilfield Company,Xi′ an,Shaanxi 710018,China
  • Online:2014-08-01 Published:2014-08-01

摘要:

致密砂岩储层孔隙结构复杂,连通性差,孔隙中流体分布不均匀,由传统方法求取阿尔奇公式中的饱和度指数n 存在较大误差,使测井计算的含油饱和度精度降低。以目标区储层岩电实验资料为依据,研究发现I − S w 关系在双对数坐标系下实验数据点比较分散,且在S w = 90% 存在明显的拐点,饱和度指数在目标区储层中不是固定值。在前人研究成果的基础上,结合配套的核磁共振实验,分析了饱和度指数n 的影响因素。其中储层孔隙结构对饱和度指数n 的影响占主要因素,孔隙结构越复杂,其值越大。针对其主控因素,结合核磁共振T2 谱采用多元回归分析法建立饱和度指数的计算模型,力求使计算的饱和度指数尽可能逼近实际值,以保证利用Archie 公式计算的含油饱和度具有较高的准确性。

关键词: 致密砂岩储层, 饱和度指数, 孔隙结构, 孔隙度, 核磁共振测井

Abstract:

The traditional statistical analysis method of computing the saturation index n in Archie equation is of low precision, because tight sandstone reservoir has complex pore structure,poor connectivity and inhomogeneity of pore fluid distribution. For this kind of reservoir,the computed oil saturation is often somewhat low. Based on lab data of petrophysical-electric property,we find the relationship between the resistivity increscent I and water saturation S w is dispersed in double logarithmic coordinate system and there exists an obvious inflection point when S w= 90%,and the saturation index n is not fixed in this kind of reservoir. On the basis of previous research results,combined with NMR,this study analyzes the influence factors of saturation index. The pore structure of reservoir rock is the major influence factor of saturation index n. The more complex pore structure,the greater the saturation index n. According to the major influence factor,and by using the multivariate regression analysis method,we established statistical model of saturation index with NMR T2 spectrum. In this way,the calculation result is approximately the same with the real value of the saturation index n which makes sure that the Archie equation applies to oil saturation calculation of reservoir with high accuracy.

Key words: tight sandstone reservoir, saturation index, pore structure, porosity, NMR logging