Research On Simulation Experiment Monitoring Of Gas Hydrate Production Based On Cross-boreholes Resistivity Imaging

As a potential new green energy source,natural gas hydrates are increasingly valued by people for exploration and development.However,the exploitation of natural gas hydrates is difficult and environmentally demanding.Large-scale mining still faces many challenges.The monitoring of hydrate reservoirs is indispensable during the process,and the monitoring technology of hydrate sub-reservoirs will become one of the focuses of future research.The high resistivity characteristics of natural gas hydrate reservoirs provide a theoretical basis for the cross-boreholes resistivity imaging monitoring technology of the reservoir.It is of great significance and practical value to carry out forward simulation research of cross-boreholes resistivity imaging monitoring technology for hydrate reservoirs according to laboratory conditions.In this paper,the forward simulation study of cross-well resistivity imaging monitoring technology is carried out at the laboratory scale for the hydrate cross-well resistivity imaging simulation experimental device.Through the understanding and understanding of the resistivity imaging principle,the basic differential equation of the cross-well DC method and the boundary value problem of the stable current field between wells are elaborated in detail.Based on the Garlerkin weighted margin method,the finite element equation of the stable current field between wells is derived.The Matlab was used to implement the 2D and 2.5D forward algorithm of the resistivity method between wells,and the sensitivity differences of different data acquisition methods were compared.Using the hydrate cross-well resistivity imaging simulation experiment device,a hydrate cross-well resistivity simulation monitoring experiment was carried out.Combining the forward simulation results,the response characteristics of the hydrate high-resistance layer model were analyzed.The main conclusions and understandings are as follows:(1)The simulation results of the forward algorithm of this paper are compared with the analytical solutions of the uniform half-space model,horizontal layered model and well data collection model,which verifies the accuracy of the algorithm program of this paper and the experiment Applicability of the device.(2)Comparing the simulation results of the 2.5D algorithm and the 2D algorithm,the simulation accuracy of the 2.5D algorithm is much higher than that of the 2D algorithm.(3)Comparing the three common well data collection methods,the four-pole collection method has the best comprehensive detection effect.(4)After analyzing the forward simulation results,it is found that the forward model of the hydrate high-resistance layer has a consistent correspondence with the response characteristics of the model.