Correction Of The Dipping Effect On The High Definition Induction Logging HDIL

With the continuous development of oil exploration technology,the number of cluster wells?branch wells and highly deviated wells increase gradually.Array induction logging curves show an abnormal phenomenon in the formation boundary,which makes many difficulties of interpretation and evaluation of oil and gas.Correction of dipping effect is a problem that must be solved when the array induction logging tool is further applied.This paper studies in detail the dipping correction of an array induction logging–High Definition Induction Logging(HDIL)with the signal processing method.The results have a great practical significance for the application of HDIL tool in deviated wells.In the first part,the geometrical factors and response characteristics in deviated well are studied.Firstly,the response characteristics of the numerical and the analytic dip geometric factors are calculated and analyzed.The results show that two methods have the similar volumetric response and the different charge response.Numerical charge geometric factor can show accurately the charge accumulation effect at the formation boundary.Secondly,conductivity contrast effect on the numerical geometrical factor is studied.Finally,the response charactoristics of dip angle on three layers of formation model with different layers and formation resistivities are analyzed.The second part is the key content of this paper.The signal processing method of dipping correction is studied in detail.A new dipping correction signal processing method based on the analytic volumetric geometrical factor and numerical charge geometrical factor is applied.The basic equations and constraints of design volume filter and charge filter are derived.The key problems in filter design are solved,including choosing objective function,converting logging deep,constrainting filter and correcting the skin effect in deviated well.The processing algorithms to eliminate the dipping effect on logging signal are designed and implemented,including the model and actual logging dataThe last part is the analysis of the effectiveness of dipping correction.Through the simulation of the three layers,ten chirp model,Oklahoma formation and the actual logging data model,the effectiveness of filters and algorithms are tested and analyzed.Through the processing of the field well data,effectiveness of the dipping effect correction are verified.Computer simulation shows that the filters and algorithm based on the new method can eliminate effectively the dipping effect on the logging data in the range of less than 75 degrees.