Analysis of elastic anisotropy of tight sandstone and the influential factors

摘要

Tight sandstone has a certain anisotropy.Using ultrasonic measurements of samples in three different directions and related matched experiments,this study systematically analyzes the pore structure and anisotropy of tight sandstone samples obtained from oil fields and compares results with those of shale.Results firstly show that the anisotropy of tight sandstone is mainly related to the compositional layering and thin interbedding which occur in different sedimentary environments.Tight sandstone has typical transverse isotropic medium characteristics,Young's modulus increases in different directions with increasing confining pressure,Poisson's ratio change is not obvious,anisotropic coefficients decrease with increasing effective pressure,and a certain linear relationship exists between ε,γ,and δ This article finally summarizes anisotropy in different areas,thereby providing a foundation for the use of suitable appraisal models in different regions.This research can be used as an experimental reference for logging evaluation,seismic data interpretation,and fracturing develop of tight sandstones.