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
This paper investigates the relation between the induced electromotive force measured by induction logging tool and the apparent conductivity, and the relation between the apparent conductivity and the formation true ...This paper investigates the relation between the induced electromotive force measured by induction logging tool and the apparent conductivity, and the relation between the apparent conductivity and the formation true conductivity. Assuming the conductivity in Green's function to be the function of the field point coordinate, the apparent conductivity expression of electric-field intensity is derived using Green's formula, and the integral equation has been established representing the relationship of the apparent conductivity with the true conductivity under this condition. The integral equation is analyzed and then leads to the conclusion that the equivalent conductivity is the apparent conductivity and the values of the apparent conductivity function contain the true conductivity, and the method derived the true conductivity from the apparent conductivity around the well axis is put forward. The validity of the approach given in this paper is verified through numerical calculation. On the basis of above means, the transmitter coil produces an electric-field distribution in formation at every point where the induction logging tool moves along a wellbore, and a number of the receiving coils obtain an apparent conductivity distribution; this is what induction electric-field logging is.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
In Dagang Oilfield in China,the utilization of the KCl polymer water-based drilling fluid(WBDF) in middeep exploration/appraisal wells presents a challenge in simultaneously optimizing resistivity logging accuracy and...In Dagang Oilfield in China,the utilization of the KCl polymer water-based drilling fluid(WBDF) in middeep exploration/appraisal wells presents a challenge in simultaneously optimizing resistivity logging accuracy and wellbore stability.To address this,it is necessary to conduct geology-engineering integration studies.Based on the formation resistivity,an analytical model was developed to assess the impact of KCl concentration in the WBDF on array induction logging response accuracy.The maximum permissible KCl concentration for the target formations was determined,and technical strategies were proposed to maintain wellbore stability at a reduced KCl concentration.After that,considering the inhibitory,encapsulating,and plugging effects,a low-KCl-concentration WBDF was optimized and applied.Model calculations demonstrate that increasing KCl concentration in the WBDF decreases resistivity,thereby reducing logging accuracy.To maintain a logging accu racy of ≥80%,the upper limits for KCl concentration in the WBDF are 4.8%,4.2%,and 3.6% for the 3rd Member of the Dongying Formation,the 1st and 2nd members of the Shahejie Formation,respectively.Cuttings recovery experiments revealed that a minimum KCl concentration of 3% is required to ensure basic shale inhibition.A combination of 3% KCl with 1% polyamine inhibitor yielded cuttings recovery and shale stability index comparable to those achieved with 7% KCl alone,and the shale inhibition performance was further enhanced with the addition of an encapsulator.The optimized WBDF has been successfully deployed in exploration/appraisal wells across multiple blocks within Dagang Oilfield,resulting in superior wellbore stability during ope rations.Furthermore,the electric logging interpre tation coincidence rate improved from 68.1% to 89.9%,providing robust te chnical support for high-quality drilling and accurate reservoir evaluation in exploration/appraisal wells.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
A hypothetical electric and magnetic induction tensor is considered in an anisotropic medium. The sources are magnetic dipoles. In such a medium, constitute parameters can be calculated by combining electric and magne...A hypothetical electric and magnetic induction tensor is considered in an anisotropic medium. The sources are magnetic dipoles. In such a medium, constitute parameters can be calculated by combining electric and magnetic field measurements. Constitutive parameters are not a scalar in this case. They are tensors, so parameters have at least both horizontal and vertical components in a uniaxial medium. These calculated parameters from the field measurement are horizontal and vertical conductivity, permittivity, and magnetic permeability. Operating frequency range is also quite large. It is up to 4 GHz. A hypothetical instrument should measure gradient fields both electric and magnetic types as well.展开更多
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supported by the National Science and Technology Major Project (Grant No. 2011ZX05020)
文摘This paper investigates the relation between the induced electromotive force measured by induction logging tool and the apparent conductivity, and the relation between the apparent conductivity and the formation true conductivity. Assuming the conductivity in Green's function to be the function of the field point coordinate, the apparent conductivity expression of electric-field intensity is derived using Green's formula, and the integral equation has been established representing the relationship of the apparent conductivity with the true conductivity under this condition. The integral equation is analyzed and then leads to the conclusion that the equivalent conductivity is the apparent conductivity and the values of the apparent conductivity function contain the true conductivity, and the method derived the true conductivity from the apparent conductivity around the well axis is put forward. The validity of the approach given in this paper is verified through numerical calculation. On the basis of above means, the transmitter coil produces an electric-field distribution in formation at every point where the induction logging tool moves along a wellbore, and a number of the receiving coils obtain an apparent conductivity distribution; this is what induction electric-field logging is.
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 (52474024)the National Oil&Gas Major Project of China (2025ZD1403200)the Program for Scientific Research Innovation Team of Young Scholars in Colleges and Universities of Shandong Province"Innovation Team of Deepwater Wellbore Fluids"(2022KJ069)。
文摘In Dagang Oilfield in China,the utilization of the KCl polymer water-based drilling fluid(WBDF) in middeep exploration/appraisal wells presents a challenge in simultaneously optimizing resistivity logging accuracy and wellbore stability.To address this,it is necessary to conduct geology-engineering integration studies.Based on the formation resistivity,an analytical model was developed to assess the impact of KCl concentration in the WBDF on array induction logging response accuracy.The maximum permissible KCl concentration for the target formations was determined,and technical strategies were proposed to maintain wellbore stability at a reduced KCl concentration.After that,considering the inhibitory,encapsulating,and plugging effects,a low-KCl-concentration WBDF was optimized and applied.Model calculations demonstrate that increasing KCl concentration in the WBDF decreases resistivity,thereby reducing logging accuracy.To maintain a logging accu racy of ≥80%,the upper limits for KCl concentration in the WBDF are 4.8%,4.2%,and 3.6% for the 3rd Member of the Dongying Formation,the 1st and 2nd members of the Shahejie Formation,respectively.Cuttings recovery experiments revealed that a minimum KCl concentration of 3% is required to ensure basic shale inhibition.A combination of 3% KCl with 1% polyamine inhibitor yielded cuttings recovery and shale stability index comparable to those achieved with 7% KCl alone,and the shale inhibition performance was further enhanced with the addition of an encapsulator.The optimized WBDF has been successfully deployed in exploration/appraisal wells across multiple blocks within Dagang Oilfield,resulting in superior wellbore stability during ope rations.Furthermore,the electric logging interpre tation coincidence rate improved from 68.1% to 89.9%,providing robust te chnical support for high-quality drilling and accurate reservoir evaluation in exploration/appraisal wells.
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.
文摘A hypothetical electric and magnetic induction tensor is considered in an anisotropic medium. The sources are magnetic dipoles. In such a medium, constitute parameters can be calculated by combining electric and magnetic field measurements. Constitutive parameters are not a scalar in this case. They are tensors, so parameters have at least both horizontal and vertical components in a uniaxial medium. These calculated parameters from the field measurement are horizontal and vertical conductivity, permittivity, and magnetic permeability. Operating frequency range is also quite large. It is up to 4 GHz. A hypothetical instrument should measure gradient fields both electric and magnetic types as well.
