| Multi-component induction logging is the rapid development of logging technology in the past ten years and belongs to the more advanced technology in the field of electrical logging.The main algorithms include multi-component inversion logging of complex strata and multi-parameter inversion techniques for multi-component induction logging data.In view of the two aspects of technical problems,many scholars at home and abroad to carry out extensive and in-depth study.For the treatment of logging data,there are two types: one is the 3D iterative inversion of the multi-component induction logging data,the other is the pre-treatment of the multi-component induction logging data,Perform 1D iterative inversion.The 3D iterative inversion of the logging data of the first type can theoretically obtain the parameters of the complex stratum by the inversion technique.However,due to the limitation of the calculation conditions,the computational workload is too large to obtain the accurate stratigraphic data The Therefore,the second kind of wellbore correction technology combined with 1D iterative inversion technique is known as a better method to solve the problem of 3D multi-component induction logging.According to our design scheme,we need to solve the following key problems for the effective processing of multi-component induction logging data: First,the establishment of complex anisotropic formation of 3D numerical simulation technology;Second,the establishment of logging equipment and supporting the wellbore correction library;Third,the development of effective wellbore correction technology to eliminate the impact of wellbore on logging data;Fourth,the design of 1D fast iterative inversion algorithm,the multi-component induction logging data inversion,access to the geological parameters,the final assessment of the reservoir.These key issues are interlocking and missing,and they need to be studied in depth.This paper focuses on the second aspect of the scheme-the establishment of multi-component induction logging wellbore correction library.Firstly,the Fourier expansion technique is used to transform the numerical simulation of the dyadic Green function of eccentricity into a series of axisymmetric problems.Then,we use the pattern matching algorithm to solve the axisymmetric problem,and obtain the semi-analytical solution of the dyadic Green function of the magnetic flux source under eccentricity in the columnar medium.Finally,combined with the structural parameters of the multi-component array induction logging tool,the calculation formula of the apparent conductivity tensor of the composite coil is deduced.The multi-component induction logging wellbore correction library is essentially a logging response library for different formation models(including different well diameter,eccentricity,mud conductivity,formation level resistivity and anisotropy coefficient).According to the actual formation data of the well site,the variation range of the corresponding parameter of the theoretical stratigraphic model is summarized.Selected 9 different borehole radius(0.06,0.08,0.10,0.12,0.14,0.16,0.18,0.20,0.22),22 different mud electrical conductivity(0.01,0.1,0.2,0.5,0.8,1.0,2.0,4.0,6.0,8.0,10.0,13.0,16.0,20.0,30.0,40.0,50.0,60.0,70.0,80.0,90.0,100.0),22 different formation conductivity(0.001,0.01,0.02,0.05,0.08,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,1.5,2.0,3.0,4.0,5.0,8.0,10.0),11 different eccentricity(0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0),and 17 different anisotropy coefficients(0.8?1.0?1.2?1.4?1.6?1.8?2.0?2.2?2.4?2.6?2.8?3.0?3.2?3.4?3.6?3.8?4.0).Based on the corresponding parameters of these theoretical stratigraphic models,a set of multi-component array induction logging wellbore correction library,which is directly applied to industrial production,is established with high efficiency and high precision.In this paper,the influence of each model parameter on the response of multi-component array induction logging tool is analyzed in detail by using the wellbore correction library. |
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