扫频介电测井响应特征与快速均质反演方法OA

To address the issues of low computational efficiency and non-uniqueness in iterative homogeneous inversion of swept-frequency dielectric logging,this paper aims to develop a fast homogeneous inversion method that balances speed and accuracy.The study is conducted using the Schlumberger's array dielectric tool(ADT)as an example.First,a homogeneous response database is calculated and established,and the tool's homogeneous response characteristics are systematically analyzed.Subsequently,based on the tool's response characteristics in different electrical property parameter intervals,a non-uniform template local refinement sampling scheme is proposed:sampling the dielectric constant with piecewise linear distribution and sampling the conductivity with log-linear distribution.Correspondingly,a fast homogeneous inversion method using this non-uniform template is developed.Optimization of the refinement sampling scheme and corresponding inversion performance tests are carried out.Finally,the proposed fast homogeneous inversion method is applied to and validated by processing data from forward modeling responses of heterogeneous models and actual field logging responses.The research results indicate:①With the increase of template sampling density,the inversion time only increases by approximately 3 times.Within the template,the mean absolute percentage errors of inverted dielectric constant and conductivity decrease by about 89.0%and 82.3%,respectively.Outside the template,these errors decrease by up to approximately 97.5%and 97.3%.This demonstrates a significant improvement in accuracy with a minor increase in computational cost,achieving a favorable balance between efficiency and precision.②For both the heterogeneous model forward responses and the field measurement data,the apparent dielectric constants and conductivities obtained by the proposed fast homogeneous inversion method for different polarizations and spacings show good agreement with the results from Schlumberger's homogeneous inversion.③The average inversion time for a single measurement point response data in a single working mode on a standard computing device is only about 4.5 ms,meeting the requirements for engineering applications.The fast homogeneous inversion method proposed in this paper provides reliable technical support for the efficient processing of swept-frequency dielectric logging data.