| The horizontal well technology is more and more concerned by the oil industry,which has become one of the most important oil field development technologies.It also represents the direction of development of petroleum technology in the new century.The horizontal well not only has brought the huge benefits in the development of oil and gas fields,but also has brought new issues to the logging and other engineering technology.In the horizontal wells,the formation interface is almost parallel to the trajectory.The response features of the induction logging tool with the formation conductivity is quite different from that of the vertical well.The signal processing method based on the geometric factor in the vertical well is not applicable.It is necessary to study the three-dimensional forward modeling method.In this paper,the High Definition Induction Log(HDIL)is used as the logging tool and the COMSOL multi-physics finite element software is used to calculate the models to establish the horizontal well information database.The database includes the horizontal well response characteristics at different field and geometric parameters.And this paper also analyzes the response characteristics of the horizontal well when drilling the fault.Finally,the inversion method based on the information base is designed,and the method which is applied to the actual production got good results.All of these provide the theoretical basis for the interpretation of the induction wells in the horizontal wells.The main contents of this paper are as following five parts:The first part mainly discusses the establishment of numerical calculation model and the structure of HDIL.Firstly,the characteristics of the formation structure of a horizontal well are analyzed.Based on the COMSOL software,the horizontal well model of a three-layer formation model structure array is established and the process and the method of grid meshing are described in detail.The correctness of the model is determined after the numerical solution is compared with the analytical solution.Finally,the structure of coils and main technical specifications of HDIL are described.The second part studies the method and process of establishing the fast forward and the base of response information with HDIL in horizontal wells.Firstly,the main parameters of the response information database and its calculation range are established by analyzing the formation information of Daqing oil field.A six-dimensional interpolation method is designed tocalculate quickly the logging response.Finally,the variation laws of response curve are analyzed with different types of well trajectories and different subarrays and frequencies,and all of these provide the basis for the design of the inversion method.The third part studies the response characteristics of HDIL in drilling faults.Firstly,the horizontal well model of drilling fault and its grid meshing are studied,and then the variation of logging response,such as fault location,fault plane inclination angle,breaking distance and formation conductivity contrast,are analyzed in detail.Finally,we propose the method ?predict the location and estimate the angle of the fault with the logging response characteristics.The fourth part studies the array induction logging inversion method of horizontal well and its application based on information base.Firstly,the mathematical model and iterative method of the conventional array induction logging inversion method are analyzed,and the logging response is analyzed for wellbore trajectory and formation conductivity inversion results.Finally,the effectiveness of the inversion method based on the information base is tested with the Zhaoping6 horizontal well.The fifth part develops an application software,which includes forward and inversion of the array induction logging in horizontal wells.Based on the MATLAB / GUI platform,the fast forward and inversion software of horizontal well is designed.It can realize the three-layer geological model and well trajectory.The logging response along the wellbore trajectory can be drawn quickly.The relative inclination of the instrument,the thickness of the target layer,the resistivity of the target layer,the resistivity of the upper wall and the resistivity of the lower rock,and the response characteristics of the calculated logging response with the remaining one parameter can be used for fabrication three-layer model response charts.When the logging response and the model parameters are given,the formation parameter or the geometric parameter can be inverted rapidly.The software interface is friendly,and can meet the engineering requirements. |
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