3-D Numerical Simulation Of Array Lateral Logging Tool

With the continuous development of the petroleum industry, the requirement of the measurement effect and precision for formation is higher and higher. The result not only need to have a high precision, but also need to reflect the layer which is very thin. At the same time, some complex formations require more parameters to be described in the oil development process. So the array lateral well logging can be better combined with the need of the study of well logging response. This paper use the method of finite element analysis to analyze the influence factors of array lateral well logging tool in vertical and skew well.Based on the theory of the finite element method and the basic principle of array lateral logging, the 3-D models of array lateral well logging which in different conditions is established by the software of model. Through the application of electromagnetic field theory and the principle of the mesh generation, mesh generation is been done for every model. The boundary condition is added to the model,and the potential value of the motor system in the all operation mode of the array lateral well logging in different formation conditions and borehole environment is statistically. Because the boundary conditions of every operation mode are different, the analysis of every model need to be set the new boundary conditions in every operation mode. The response characteristics of the instrument are analyzed by calculating the value of potential in all model with every operating mode and the value of the apparent resistivity.In the vertical wells, because of the effect of the measurement results of the array lateral logging by many factors, the model with different borehole conditions, different mud invasion and different formation thickness is calculated.When the borehole conditions in the borehole radius is smaller or mud resistivity is close to the true formation resistivity,the apparent resistivity which is got by array lateral logging responses is closer to the true formation resistivity.When the instrument is in the case of the eccentricity, the apparent resistivity has a tendency to become larger, but it is not obvious.When the mud invasion for array lateral logging with different depths,the apparent resistivity values influence is a step like change.The more shallow the working mode, the greater the impact caused by the mud invasion and the sooner close to the mud resistivity.When the formation thickness is larger than 0.5m,the apparent resistivity is less affected by the surrounding rock.The influence of the array lateral logging by changing the size of the internal electrode system can be analyzed to get a appropriate electrode size.In the homogeneous case, the apparent resistivity values is closer to the true resistivity of the target layer with the increase of electrode size.In the multi-layer media case,the size of the instrument itself is increase with the the electrode size becomes large,it brings about the decrease of the sensitivity of the instrument to the thin layer.Compared with vertical wells, due to the deviation angle,the influence factors of array lateral logging in two kind of wells may have different effects.Finite element analysis the model of array lateral logging can be found that the influence of array lateral logging response by the target layer thickness and mud invasion of of and is very similar with the influence of the diameter. And the influence by deviation angle is only have a minor effect on the depth of the RAL5.