论文部分内容阅读
砂岩气藏地层压力下降岩石发生非线弹性变形时,定量研究非线弹性岩石体积应变的大小是个难点。由非线弹性岩石弹性模量与有效压力满足的乘幂关系,推导了地面实验和地层条件岩石体积应变理论关系,提出了一种定量研究岩石体积应变的试算迭代法,并结合岩石变形实验岩石体积应变与有效压力变化数据,求取了岩石非线弹性变形常数a、b值,定量预测了非线弹性岩石体积应变的大小。该方法应用表明,地面实验条件非线弹性岩石体积应变、孔隙度、地层压力下降孔隙度实验预测值或实测值与该方法预测值相对误差分别为≤7.39%、≤0.80%和≤3.92%,具有较好的吻合性,能够实现地面实验数据向地层条件数据的转换,为定量研究非线弹性岩石体积应变提供了有效途径。
It is a difficult point to quantitatively study the volumetric strain of nonlinear elastic rock when the rock of sandstone gas reservoir descends into nonlinear elastic deformation. Based on the exponential relationship between the elastic modulus and the effective pressure of nonlinear elastic rock, the theoretical relationship between the ground experiment and the rock mass volume strain is deduced. A trial iterative method to quantitatively study the rock volume and strain is proposed. Combined with the rock deformation experiment Rock volumetric strain and effective pressure change data, the nonlinear elastic deformation constants a and b of the rock are obtained, and the volume and strain of the nonlinear elastic rock are quantitatively predicted. The application of this method shows that the relative errors between the experimental or predicted values of porosity and porosity, formation pressure drop porosity and the predicted values of the nonlinear elastic rock under the ground experimental conditions are respectively ≤7.39%, ≤0.80% and ≤3.92% It has better coincidence, which can change the data of ground test data to the formation condition data, which provides an effective way to quantitatively study the volume strain of nonlinear elastic rock.