We have developed a novel method for correcting resistivity anisotropy in array induction logging(AIL)for shale reservoirs drilled with horizontal wells.This method is featured by two aspects:simplifying software focu...We have developed a novel method for correcting resistivity anisotropy in array induction logging(AIL)for shale reservoirs drilled with horizontal wells.This method is featured by two aspects:simplifying software focusing(SF)algorithm from two-dimensional(2D)to one-dimensional(1D)and approximately decoupling the resistivity anisotropy effect.Initially,the typical raw and focused AIL responses are simulated to determine the applicability of the 2D SF algorithm in deviated and horizontal wells.The non-necessity of SF algorithm along vertical direction is also proved for the pure horizontal wells.Subsequently,a 1D SF algorithm that focuses only along the radial direction in horizontal wells is developed to replace the original 2D SF algorithm.This new method eliminates the opacity of traditional SF algorithms and can be easily applied to different AIL tools.The sensitivity of AIL to resistivity anisotropy in homogeneous and layered formations is then discussed,showing that the anisotropy effect can be separated from other effects.Finally,an efficient anisotropy correction scheme using the Levenberg-Marquardt algorithm is established to quickly and accurately correct AIL data in horizontal wells.Results from simulated and measured data demonstrate that this new method effectively removes the anisotropy effect and provides accurate horizontal resistivity for shale beds drilled with horizontal wells.Compared with existing methods,it is significantly faster and compatible with AIL tools from various companies,laying solid foundation for the interpretation and evaluation of shale reservoirs in horizontal wells.展开更多
Delineation of bed boundaries based on resistivity logging curves is important prior information for the inversion and interpretation of resistivity logging data.Traditionally,the layering algorithm mainly use the der...Delineation of bed boundaries based on resistivity logging curves is important prior information for the inversion and interpretation of resistivity logging data.Traditionally,the layering algorithm mainly use the derivatives of resistivity curves or other logging methods as reference.However,measurement error or resolution mismatch may lead to misjudgment of the boundary.In view of the shortcomings of traditional methods,this paper presents an automatic layering algorithm of array induction logging curves based on deep learning.In this algorithm,a locally connected convolution neural network is used,and the generalization ability of the network is improved by enlarging the training set,optimizing the window length and threshold,and strengthening the layering effect.Simulation and field data show the eff ectiveness of the proposed algorithm.展开更多
The construction of a borehole correction library for the multi-component array induction tool in deviated boreholes involves extensive 3D forward modeling and typically requires significant computational resources.To...The construction of a borehole correction library for the multi-component array induction tool in deviated boreholes involves extensive 3D forward modeling and typically requires significant computational resources.To address this challenge,this paper proposes an efficient algorithm for the library construction based on the 3D finite volume method(FVM)and contraction high-order Born approximation(CHBA).First,the electromagnetic(EM)field solution region is divided into two symmetric subregions based on the symmetry of the correction library model and the EM field.Numerical solution on a single subregion,combined with the symmetry boundary extension technique,enhances the efficiency of the 3D numerical simulation.Second,three reference mud conductivities are selected based on the mud conductivity range,and the CHBA is applied to calculate the EM responses at all mud conductivity nodes rapidly.Third,the number of forward simulation operations is further reduced by exploiting the principle that models with different frequencies and different formation conductivities have equivalent EM responses.Numerical experiments demonstrate the correctness and feasibility of the proposed algorithm.Compared to conventional 3D modeling,the proposed algorithm achieves approximately a 20-fold speedup in library construction,effectively reducing computational resources and time consumption.展开更多
With the help of the modified geometrical factor theory, the Marquardt method was used to calculate the true electrical parameters of the formation from array induction logs. The inversion results derived from the ass...With the help of the modified geometrical factor theory, the Marquardt method was used to calculate the true electrical parameters of the formation from array induction logs. The inversion results derived from the assumed model and some practical cases show that the rebuilt formation profile determined by 2-ft resolution array induction logs is reasonable when the formation thickness is greater than 1 m, which thus indicates that the inversion method is reliable and can provide quantitative information for the discrimination of oil/gas or water zone.展开更多
Permeability is an important index in reservoir evaluation,oil and gas accumulation control,and production effi ciency.At present,permeability can be obtained through several methods.However,these methods are not suit...Permeability is an important index in reservoir evaluation,oil and gas accumulation control,and production effi ciency.At present,permeability can be obtained through several methods.However,these methods are not suitable for tight sandstone in general because the pore type in tight sandstone is mainly secondary pores and has the characteristics of low porosity and permeability,high capillary pressure,and high irreducible water saturation.Mud invasion depth is closely related to permeability during drilling.In general,the greater the permeability,the shallower the mud invasion depth,and the smaller the permeability,the deeper the mud invasion depth.Therefore,this paper builds a model to predict the permeability of tight sandstone using mud invasion depth.The model is based on the improvement of the Darcy flow equation to obtain permeability using mud invasion depth inversion of array induction logging.The influence of various permeability factors on the model is analyzed by numerical simulation.The model is used to predict the permeability of tight sandstone in the south of the Ordos Basin.The predicted permeability is highly consistent with the core analysis permeability,which verifi es the reliability of the method.展开更多
基金supported in part by the Oil&Gas Major Project of China,Grant No.2025ZD1401105National Natural Science Foundation of China,Grant Nos.42474152,U23B2086 and 42374150+1 种基金Shandong Provincial Natural Science Foundation,Grant No.ZR2023MD053the CNPC Innovation Foundation,Grant No.2024DQ02-0152.
文摘We have developed a novel method for correcting resistivity anisotropy in array induction logging(AIL)for shale reservoirs drilled with horizontal wells.This method is featured by two aspects:simplifying software focusing(SF)algorithm from two-dimensional(2D)to one-dimensional(1D)and approximately decoupling the resistivity anisotropy effect.Initially,the typical raw and focused AIL responses are simulated to determine the applicability of the 2D SF algorithm in deviated and horizontal wells.The non-necessity of SF algorithm along vertical direction is also proved for the pure horizontal wells.Subsequently,a 1D SF algorithm that focuses only along the radial direction in horizontal wells is developed to replace the original 2D SF algorithm.This new method eliminates the opacity of traditional SF algorithms and can be easily applied to different AIL tools.The sensitivity of AIL to resistivity anisotropy in homogeneous and layered formations is then discussed,showing that the anisotropy effect can be separated from other effects.Finally,an efficient anisotropy correction scheme using the Levenberg-Marquardt algorithm is established to quickly and accurately correct AIL data in horizontal wells.Results from simulated and measured data demonstrate that this new method effectively removes the anisotropy effect and provides accurate horizontal resistivity for shale beds drilled with horizontal wells.Compared with existing methods,it is significantly faster and compatible with AIL tools from various companies,laying solid foundation for the interpretation and evaluation of shale reservoirs in horizontal wells.
基金the National Nature Science Foundation of China(No.41604123)。
文摘Delineation of bed boundaries based on resistivity logging curves is important prior information for the inversion and interpretation of resistivity logging data.Traditionally,the layering algorithm mainly use the derivatives of resistivity curves or other logging methods as reference.However,measurement error or resolution mismatch may lead to misjudgment of the boundary.In view of the shortcomings of traditional methods,this paper presents an automatic layering algorithm of array induction logging curves based on deep learning.In this algorithm,a locally connected convolution neural network is used,and the generalization ability of the network is improved by enlarging the training set,optimizing the window length and threshold,and strengthening the layering effect.Simulation and field data show the eff ectiveness of the proposed algorithm.
基金funded by the Forward-looking Basic Science and Technology Research Project of PetroChina Company Limited(2025DJ104)the National Natural Science Foundation of China(42174150)the National Science and Technology Major Project for Deep Earth Probe and Mineral Resources Exploration(2024ZD1003005).
文摘The construction of a borehole correction library for the multi-component array induction tool in deviated boreholes involves extensive 3D forward modeling and typically requires significant computational resources.To address this challenge,this paper proposes an efficient algorithm for the library construction based on the 3D finite volume method(FVM)and contraction high-order Born approximation(CHBA).First,the electromagnetic(EM)field solution region is divided into two symmetric subregions based on the symmetry of the correction library model and the EM field.Numerical solution on a single subregion,combined with the symmetry boundary extension technique,enhances the efficiency of the 3D numerical simulation.Second,three reference mud conductivities are selected based on the mud conductivity range,and the CHBA is applied to calculate the EM responses at all mud conductivity nodes rapidly.Third,the number of forward simulation operations is further reduced by exploiting the principle that models with different frequencies and different formation conductivities have equivalent EM responses.Numerical experiments demonstrate the correctness and feasibility of the proposed algorithm.Compared to conventional 3D modeling,the proposed algorithm achieves approximately a 20-fold speedup in library construction,effectively reducing computational resources and time consumption.
文摘With the help of the modified geometrical factor theory, the Marquardt method was used to calculate the true electrical parameters of the formation from array induction logs. The inversion results derived from the assumed model and some practical cases show that the rebuilt formation profile determined by 2-ft resolution array induction logs is reasonable when the formation thickness is greater than 1 m, which thus indicates that the inversion method is reliable and can provide quantitative information for the discrimination of oil/gas or water zone.
基金supported by the National Natural Science Foundation of China project(No.41504103 and No.41804097).
文摘Permeability is an important index in reservoir evaluation,oil and gas accumulation control,and production effi ciency.At present,permeability can be obtained through several methods.However,these methods are not suitable for tight sandstone in general because the pore type in tight sandstone is mainly secondary pores and has the characteristics of low porosity and permeability,high capillary pressure,and high irreducible water saturation.Mud invasion depth is closely related to permeability during drilling.In general,the greater the permeability,the shallower the mud invasion depth,and the smaller the permeability,the deeper the mud invasion depth.Therefore,this paper builds a model to predict the permeability of tight sandstone using mud invasion depth.The model is based on the improvement of the Darcy flow equation to obtain permeability using mud invasion depth inversion of array induction logging.The influence of various permeability factors on the model is analyzed by numerical simulation.The model is used to predict the permeability of tight sandstone in the south of the Ordos Basin.The predicted permeability is highly consistent with the core analysis permeability,which verifi es the reliability of the method.
