疏松砂岩储层单轴应力敏感特征测试分析

Test and Analysis of Uniaxial Stress Sensitivity Characteristics of Unconsolidated Sandstone Reservoir

测井中往往是根据三轴岩心测试结果来推导单轴应力下的孔隙度校正关系,这可能不适合疏松砂岩储层。针对岩石只在单向上或者垂向上产生形变的情况,设计单轴应力敏感测试装置,对取自渤海辽东湾疏松砂岩油气藏的12块岩心样品,测试分析单轴应力条件下的孔隙度、渗透率及岩石压缩系数变化规律。实验结果表明,在单轴应力条件下,岩心孔隙度与有效应力存在较好线性关系,岩心渗透率与有效应力存在幂函数关系和线性关系。疏松砂岩储层物性具有较强的应力敏感特征。

Porosity correction under uniaxial stress is often derived from tri-axial core test results,which may not be suitable for unconsolidated sandstone reservoirs.Aiming at the case that the rock deforms only in one direction or in the vertical direction,a uniaxial stress sensitive test device is designed to conduct and analyze the laws of porosity,permeability and rock compressibility of 12 core samples taken from unconsolidated samples in Bohai Bay fields.The experimental results show that the core porosity has a good linear relationship with effective stress,and the core permeability shows a power function relationship and also a linear relationship with stress.In general,physical properties of unconsolidated sandstone reservoirs show strong stress sensitivity characteristics.