The Calculation Based On Lateral Constraint And The Application Of The Water Content And Relaxation Time Of MRS

Being thirst for the water resource and the prevention of the water disasters are more serious problems in our country. The Magnetic Resonance Sounding(MRS) has developed a new generation of the earth geophysical detection technology because it has the features like direct detection and quantitative calculation of groundwater, etc. However,due to the complexity of the stratum structure and the difference of the aquifers’ thickness,etc., the current 2D MRS calculation method that is about the water content and relaxation time still has some shortcomings, for example it can not accurately explain the interface location information about the aquifers and impermeable layers. At the same time, with the depth increasing or the aquifers’ thickness thinning, the calculation resolution will decrease and the effect of the aquifer detection will also have a significant decrease. To solve these problems, this paper has researched the calculation method about the water content and relaxation time of the Magnetic Resonance Sounding that is based on lateral constraint theory and put forward the quasi two-dimensional Block calculation method that is based on the total nuclear magnetic resonance’s data signal. This method can effectively utilize all the data signal to complete the large-scale groundwater resources’ layered quasi two-dimensional calculation imaging; and then complete the calculation process of the two-dimensional MRS simulation models and the field data by utilizing the A one-dimensional single point calculation and quasi-two-dimensional Block calculation.The calculation results are compared.The paper proposes the Block calculation method on the problems that the current MRS Smooth calculation has a poor stability on the deep aquifer and thin aquifer’s calculation and inaccurate information on the aquifer location. The Block calculation method is based on the priori information, and constructs a complex model including the upper aquifer and the lower aquifer, and utilizes Smooth and Block calculation to the simulation and calculation analysis. The result shows that the Block calculation method based on the prior information meets the accuracy and stability of the calculation requirement, and the deep aquifer that has the internal complex structure can be provided the compartments’ complete information.Based on the shortcomings that with the MRS depth increasing, calculation resolution decreases and the calculation has a poor stability, etc., this paper introduces a lateral constraint matrix, and derives the quasi two-dimensional calculation method based on thelateral constraint. Then this paper completes that converts the target matrix into the iterative format equations and uses conjugate gradient algorithm to solve. The paper has realized the formula derivation of the quasi two-dimensional calculation based on the lateral constraint, which can obtain a one-time quasi two-dimensional MRI results. The paper has established flat surface continuous aquifers model and non flat surface continuous aquifers model.By constructing a two-dimensional groundwater model, using the one-dimensional Block calculation method and the quasi two-dimensional Block calculation method based on the lateral constraint to simulate, this paper has completed the analysis of the two calculation methods’ results and verify the high resolution of the deep and thin aquifers by the method of quasi two-dimensional block calculation method.Finally, using the one-dimensional Block calculation method and the lateral constraint based quasi two-dimensional Block calculation method, the MRS data of a Mongolian mining area’s two section planes is calculated,then the results of the two calculation methods are compared and analysis the accuracy of the calculation results, which shows the high resolution of the quasi two dimensional block calculation method.The paper complete the comparative analysis with the drilling data of the geological exploration to verify the validity and usefulness of the quasi two-dimensional Block calculation method based on lateral restraint.