基于核磁与压汞资料的储层孔隙结构特征研究

X1井区位于酒泉盆地营尔凹陷长沙岭构造带，下白垩统下沟组一段（K₁g¹）储层岩石类型主要为岩屑砂岩和长石岩屑砂岩，发育砂泥岩薄互层，储层非均质性强，给储层评价带来较大困难。而流体识别、储层评价及后期开发措施在很大程度上依赖于对储层的孔隙结构的认识。以X1井区为例，对研究区的矿物成分进行统计分析、对电镜薄片观测的孔隙类型进行分类研究，重点根据该井区的压汞及核磁共振T₂谱等测试数据，建立了T₂谱与岩芯孔喉半径的定量计算方法，并结合核磁共振测井资料，形成了连续定量刻画储层孔喉半径变化特征的方法；对孔喉半径的定量刻画，可以为了解储层孔渗的变化提供思路，为研究区储层孔隙结构和储层非均质性研究提供更丰富的信息。

A Study on the Characteristics of Reservoir Pore Structure Based on Nand Mercury Injection Data

X1 Wellblock is located in the Changshaling structural belt of Ying'er Sag, Jiuquan Basin. The rock types of this reservoir of the first member in Xiagou Formation of Lower Crataceous are mainly lithic sandstone and feldspar lithic sandstone. Reservoir heterogeneity is strong, and thin interbedded sand and mudstone are especially developed, which brings great difficulties to reservoir comprehensive evaluation. However, fluid identification, reservoir evaluation and later development measures depend on the overall understanding of pore structure of reservoir to a large extent. Taking X1 Wellblock in Changshaling as an example, the statistical analysis was carried out on the mineral composition in the study area, the pore types are classified study of electron microscopic thin section(SEM) observation, and then the key works, under the wellblock of mercury injection and nuclear magnetic resonance T₂ spectrum of test data, established the quantitative calculation methods of core pore throat radius and the T₂ relaxation time spectrum, and connecting with the nuclear magnetic resonance (NMR) logging data. A method for continuously and quantitatively characterizing the variation characteristics of reservoir pore-throat radius is developed. The quantitative characterization of pore-throat radius can provide ideas for us to understand the change of reservoir porosity and permeability, and provide more abundant information for the study of reservoir pore structure and reservoir heterogeneity.