The Research On Multi-Component Induction Logging While Drilling Response And Interpretation Method

In the anisotropic formation, these logging responses are very different from those responses of traditional vertical borehole in isotropic formation. So, researching electromagnetic logging response in anisotropic formation has important signification to the explanation of log information and geological evaluation. Because measuring characteristics of logging tools and difference of formation resistivities in directions have not benn considered synthetically, errors often arise in the saturation evaluation of electrical anisotropy reservoir with low-resistivity. A multi-component induction tool provides direct measurements to derive both horizontal and vertical resistivities that allow accurate evaluation of the anisotropy reservoirs.Because of the advantages of its own,multi-component induction logging instrument have been used more and more to measure the high angle wells and horizontal wells in complex formation anisotropy. As well, these measurements for the precise description of the anisotropic formation are essential. A multi-component induction logging instrument is comprised of three mutually orthogonal transmitter-receiver pairs that allow measurement of all nine magnetic field components at multiple frequencies.In anisotropic formations these measurents contain sufficient information to determine horizontal and vertical resistivities and to calculate the structural formation dip and azimuth.In this paper, The dyadic Green's G^ME (r,r') and G^MH(r,r') in layered anisotropic formation was developed. How to determine the Sommerfeld integral determined coefficient of equation group by recursive algorithm was deduced particularly. The expression of the obtained dyadic Green's function is terse in form and is easy to be programmed, and it doesn't overflow. Then, this method program is compiled on the Fortran power station4.0 software. The formula to compute the MCIL response is given. And then,numerial tests are carried out to validate the algorithm. The response of multi-component induction logging in layered anisotropic and deviated formation is computed by using the dyadic Green's function. The influence of coil distance, bed thickness, deviated angle and surrounding shale on the response of multi-component induction logging is analyzed. Using the homogeneous formation of conductivity depending on the scale drawing board to inversion (interpretation) of anisotropic layered media stratigraphic level of electrical conductivity and vertical conductivity, and the results provide an important reference value to evaluate formation and Logging data interpretation.