Non-homogeneous Characterization of Chang3 Sandstones in the Baipao Area of the Ordos Basin

Abstract

The Chang3 formation group in the Baibao area has a large variation of distribution both vertically and horizontally, resulting in a high degree of reservoir non-homogeneity and increasing the difficulty of reservoir exploration and development. This leads to strong reservoir in homogeneity, which increases the difficulty of reservoir exploration and development. In this paper, the non-homogeneity characteristics of the Chang3 oil formation group are studied in depth from both macroscopic and microscopic aspects by means of core observation, cast thin section identification, scanning electron microscope analysis and well logging data statistics. The results show that: The Chang3 oil formation group is mainly deposited at the front edge of the delta, and spreads in the under water diversion channel; the sandstone clasts in the reservoir of Chang 3 Reservoir mainly consist offeldspar and quartz, and the particles mainly consist of fine grains, with good particle sorting; thereservoir variability coeficient, extreme deviation, stratification coefficient and sandstone density areall very high, and the development of parallel lami nations, horizontal lami nations, plate inter layers and groove interlayers, with strong, inter layer and intra layer non-homogeneity;, the variation range of theme dian radius of the pore is not wide, and the physical characteristics are relatively poor. Theme dian radius of pore space varies little, the physical characteristics are poor, and it belongs to low porosity, extra low porosity-low permeability reservoir, with relatively strong microscopic non-homogeneity;, the planar non-homogeneity is strengthened with the change of the width of the river channel, and the sand body spreads continuously in sheets, and the section is in the shape of a plate or asymmetric lenticular, and the sand body has the flow ability, with strong planar non-homogeneity.