Study On The CT Imaging Technology Between Cross-well And Borehole

With the rapid development of the country's economy and the continuous increase of the urbanization population,the pressure of urban living space has become more and more intense,with the problems of tight land resources,the reduction of green space,the explosion of urban population,traffic jams,increased energy consumption,and increasingly serious environmental pollution.In addition to the traditional use of space in sky,the development and utilization of underground space is one of the solutions to the above problems.We can effectively detect the underground stratum structure and understand the size,morphology,and spatial distribution of anomalous bodies in the detection area by cross-hole seismic.However,when the exploration results are combined with the drilling data,the exploration range is limited,the data is not matched with the drilling data,and the accuracy is not high enough.Through the joint construction of VSP logging,cross-well and well-ground seismic,constrained with logging data,after the joint inversion of the data,the formation information on the drilling can be more fully understood,the imaging accuracy of cross-well seismic is improved,and further solutions The problem of urban underground space is of great significance.Cross-well seismic CT imaging is one of the key steps in cross-well seismic data processing technology and an effective method for inversion of geological models.In this paper,numerical simulation is used to realize VSP seismic logging,cross-well CT and well-site RVSP imaging.It is necessary to establish different stratigraphic model,forward simulate the well logging,cross-well and well-ground seismic data,and analyze the advantages of the three methods of inversion results.Study on using VSP seismic logging data to improve imaging accuracy.The cross-well CT imaging results are used as the basic velocity model,on the basis of which the logging data and well-field data are combined separately,and the effect of the logging data on the resolution of the cross-well CT inversion imaging is analyzed.The advantages of the three methods are comprehensively analyzed and combined.First,the inversion results of a single log data are compared with the forward model data.Then,through programming and model design,the log and the well are combined,and the combination of well and ground is compared with the results between the basic wells,and the expected results are finally obtained.In the process of moving from experimental simulation to practical application,the problem of inconsistent excitation and affecting data results is solved,and the application problem in actualengineering is successfully solved.This paper combines experimental data and practical application data to obtain the following conclusions:(1)After combined with VSP seismic logging data,the data on the drilling can be effectively constrained during the inversion process to improve the ray density and imaging accuracy and be consistent with the drilling data;(2)the accuracy of borehole seismic affected by the offset has some limitations,in practical engineering applications need to consider the efficiency of engineering problems associated with offset size.In this paper,the well logging,well to well,well to ground seismic CT combined imaging method is used to design the construction of the cross well seismic engineering examples and to carry out the combined imaging analysis,which has achieved good results,can get the cross well,well to well,well side of the CT profile,improve the accuracy of cross well seismic exploration.Therefore,the joint imaging method has certain practicability and effectiveness.The paper has 71 figures,15 tables,and 100 references.