MRS Response of Water-bearing Geological Body of Coal in Uniform Conductivity

The MRS forward calculation of 3D water-contained medium involves two difficulties. First of them is to calculate the expression of the exciting field, which is an integration including 2 Bessel functions’ product. In this paper, the integration was divided into 2 integral intervals. In the first interval, using the Hankel expression of Bessel functions and the latter asymptotic properties of large volume, the double bessel integration was converted into Fourier sine(cosine) transformations and fast calculation to the transformations was adopted to finish the integration in this interval. Traditional calculation method can achieve high accuracy in the second interval. The second difficulty is the space dicretization of the 3D water-contained medium. Dicretization methods in both cylindrical and rectangular coordinates system were introduced in this paper. The cubic grids in rectangular coordinates system can construct 3D water-contained bodies of any shape. At last, MRS forward calculation of 3D water-contained bodies in uniform media achieved. Based on what mentioned above, water-filled tunnel and water-filled gob models are build, and both models MRS forward curves are calculated.