Casing damage resulting from sand production in unconsolidated sandstone reservoirs can significantly impact the average production of oil wells.However,the prediction task remains challenging due to the complex damag...Casing damage resulting from sand production in unconsolidated sandstone reservoirs can significantly impact the average production of oil wells.However,the prediction task remains challenging due to the complex damage mechanism caused by sand production.This paper presents an innovative approach that combines feature selection(FS)with boosting algorithms to accurately predict casing damage in unconsolidated sandstone reservoirs.A novel TriScore FS technique is developed,combining mRMR,Random Forest,and F-test.The approach integrates three distinct feature selection approaches—TriScore,wrapper,and hybrid TriScore-wrapper and four interpretable Boosting models(AdaBoost,XGBoost,LightGBM,CatBoost).Moreover,shapley additive explanations(SHAP)was used to identify the most significant features across engineering,geological,and production features.The CatBoost model,using the Hybrid TriScore-rapper G_(1)G_(2)FS method,showed exceptional performance in analyzing data from the Gangxi Oilfield.It achieved the highestaccuracy(95.5%)and recall rate(89.7%)compared to other tested models.Casing service time,casing wall thickness,and perforation density were selected as the top three most important features.This framework enhances predictive robustness and is an effective tool for policymakers and energy analysts,confirming its capability to deliver reliable casing damage forecasts.展开更多
Resin plugging agents play a pivotal role in addressing casing damage in oil and gas fields.However,the widespread use of epoxy resin is constrained by its high cost and non-renewable origin,while plant-based resins o...Resin plugging agents play a pivotal role in addressing casing damage in oil and gas fields.However,the widespread use of epoxy resin is constrained by its high cost and non-renewable origin,while plant-based resins often suffer from inadequate mechanical properties,which limit their effectiveness in such applications.This study introduces BEOPA,an innovative,renewable,high-strength resin plugging agent derived from epoxidized soybean oil(ESO)and enhanced with bisphenol A-type benzoxazine(BZ).In this study,the synthesis process,reactionmechanism,and application performance of this novelmaterial are systematically presented,explored and optimized.It is shown that the optimal formulation of BEOPA includes 41.4 wt%ESO,24.8 wt%BZ,24.8 wt%methylhexahydrophthalic anhydride(MHHPA),8.2 wt%styrene(ST),and 0.8 wt%N,N-dimethylbenzylamine(BDMA),yielding an impressive compressive strength of 93.7 MPa.The integration of ESO and BZ creates an intricate and robust double crosslinking network,significantly enhancing material strength and durability.BEOPA exhibits a tunable curing time,ranging from 0.5 to 15 h,with viscosities below 300 mPa⋅s at 25℃and 75mPa⋅s at 50℃.Furthermore,it demonstrates exceptional thermal stability within the 100℃-150℃range,even in environments with mineral salt concentrations as high as 43,330 mg/L.Remarkably,BEOPA achieves superior plugging performance,sustaining breakthrough pressures exceeding 29.7 MPa in 1 mm crack cores.展开更多
The casing damage has been a big problem in oilfield production. The current detection methods mostly are used after casing damage, which is not very effective. With the rapid development of China's offshore oil i...The casing damage has been a big problem in oilfield production. The current detection methods mostly are used after casing damage, which is not very effective. With the rapid development of China's offshore oil industry, the number of offshore oil wells is becoming larger and larger. Because the cost of offshore oil well is very high, the casing damage will cause huge economic losses. What's more, it can also bring serious pollution to marine environment. So the effective methods of detecting casing damage are required badly. The accumulation of stress is the main reason for the casing damage. Magnetic anisotropy technique based on counter magnetostriction effect can detect the stress of casing in real time and help us to find out the hidden dangers in time. It is essential for us to prevent the casing damage from occurring. However, such technique is still in the development stage. Previous studies mostly got the relationship between stress and magnetic signals by physical experiment, and the study of physical mechanism in relative magnetic permeability connecting the stress and magnetic signals is rarely reported. The present paper uses the ANSYS to do the three-dimensional finite element numerical simulation to study how the relative magnetic permeability works for the oil casing model. We find that the quantitative relationship between the stress' s variation and magnetic induction intensity's variation is: Δδ =K* ΔB, K = 8.04×109, which is proved correct by physical experiment.展开更多
In the ChangningeWeiyuan national shale gas demonstration area,SW Sichuan Basin,the wellbore integrity damage occurs in some shale gas wells and has direct effect on the gas production rate of single shale gas horizon...In the ChangningeWeiyuan national shale gas demonstration area,SW Sichuan Basin,the wellbore integrity damage occurs in some shale gas wells and has direct effect on the gas production rate of single shale gas horizontal well.After statistics analysis was performed on the problems related with wellbore integrity,such as casing damage,casing running difficulty and cement sheath blow-by,the multi-factor coupling casing stress calculation and evaluation mode laws established.Then study was conducted on the influential mechanism of multi-factor coupling(temperature effect,casing bending and axial pressure)on casing damage.The shale slip mechanism and its relationship with casing sheared formation were analyzed by using the MohreCoulomb criterion.Inversion analysis was performed on the main controlling factors of casing friction by using the developed casing hook load prediction and friction analysis software.And finally,based on the characteristics of shale gas horizontal wells,wellbore integrity control measures were proposed in terms of design and construction process,so as to improve the drilling quality(DQ).More specifically,shale gas well casing design calculation method and check standard were modified,well structure and full bore hole trajectory design were optimized,drilling quality was improved,cement properties were optimized and cement sealing integrity during fracturing process was checked.These research findings are significant in the design and management of future shale gas borehole integrity.展开更多
Du 813 super-heavy oil reservoir has been comprehensively treated to solve the problems of high viscosity of crude oil, short steam injection period, high steam injection pressure and low reserve control degree. By de...Du 813 super-heavy oil reservoir has been comprehensively treated to solve the problems of high viscosity of crude oil, short steam injection period, high steam injection pressure and low reserve control degree. By deploying new wells, casing damage well treatment and steam huff and puff technology research, the existing problems in block development have been effectively solved, and the block output has been increased.展开更多
The casing damage is a serious problem when the steam-injection method is applied in the oilfields. In this work, the commercial software ANSYS is used to predict the thermal expansion and the thermal stresses of casi...The casing damage is a serious problem when the steam-injection method is applied in the oilfields. In this work, the commercial software ANSYS is used to predict the thermal expansion and the thermal stresses of casings in steam-injection wells under different conditions, including steam channeling, well shut-in and cavitation in cement ring. The results indicate that nearly no temperature change occurs in oil-layer areas 4.0 m-6.0 m away from the casing center. When steam channeling appears, the maximum Mises stress of both the casing and the cement ring occurs on the interior wall. During the shut-in operation, while the maximum thermal expansion ocurs within the temperature-transition area, the maximum thermal stress will be on the interior wall of casing, exceeding the thermo-elastic yield ultimate stress of N80 steel. Besides, the thermal stress is much higher than the elastic strain limit if certain amounts of cavitations appear in the cement ring. Based on the results, some preventive measures against casing damage are proposed, which are verified through the successful application of TP120TH casings during well completion in Liao＇he oilfield.展开更多
基金funded by the National Natural Science Foundation Project(Grant No.52274015)the National Science and Technology Major Project(Grant No.2025ZD1402205)。
文摘Casing damage resulting from sand production in unconsolidated sandstone reservoirs can significantly impact the average production of oil wells.However,the prediction task remains challenging due to the complex damage mechanism caused by sand production.This paper presents an innovative approach that combines feature selection(FS)with boosting algorithms to accurately predict casing damage in unconsolidated sandstone reservoirs.A novel TriScore FS technique is developed,combining mRMR,Random Forest,and F-test.The approach integrates three distinct feature selection approaches—TriScore,wrapper,and hybrid TriScore-wrapper and four interpretable Boosting models(AdaBoost,XGBoost,LightGBM,CatBoost).Moreover,shapley additive explanations(SHAP)was used to identify the most significant features across engineering,geological,and production features.The CatBoost model,using the Hybrid TriScore-rapper G_(1)G_(2)FS method,showed exceptional performance in analyzing data from the Gangxi Oilfield.It achieved the highestaccuracy(95.5%)and recall rate(89.7%)compared to other tested models.Casing service time,casing wall thickness,and perforation density were selected as the top three most important features.This framework enhances predictive robustness and is an effective tool for policymakers and energy analysts,confirming its capability to deliver reliable casing damage forecasts.
基金supported by the National Natural Science Foundation of China(U23B20156,52174033).
文摘Resin plugging agents play a pivotal role in addressing casing damage in oil and gas fields.However,the widespread use of epoxy resin is constrained by its high cost and non-renewable origin,while plant-based resins often suffer from inadequate mechanical properties,which limit their effectiveness in such applications.This study introduces BEOPA,an innovative,renewable,high-strength resin plugging agent derived from epoxidized soybean oil(ESO)and enhanced with bisphenol A-type benzoxazine(BZ).In this study,the synthesis process,reactionmechanism,and application performance of this novelmaterial are systematically presented,explored and optimized.It is shown that the optimal formulation of BEOPA includes 41.4 wt%ESO,24.8 wt%BZ,24.8 wt%methylhexahydrophthalic anhydride(MHHPA),8.2 wt%styrene(ST),and 0.8 wt%N,N-dimethylbenzylamine(BDMA),yielding an impressive compressive strength of 93.7 MPa.The integration of ESO and BZ creates an intricate and robust double crosslinking network,significantly enhancing material strength and durability.BEOPA exhibits a tunable curing time,ranging from 0.5 to 15 h,with viscosities below 300 mPa⋅s at 25℃and 75mPa⋅s at 50℃.Furthermore,it demonstrates exceptional thermal stability within the 100℃-150℃range,even in environments with mineral salt concentrations as high as 43,330 mg/L.Remarkably,BEOPA achieves superior plugging performance,sustaining breakthrough pressures exceeding 29.7 MPa in 1 mm crack cores.
基金supported by the National Natural Science Foundation of China(No.41174157)
文摘The casing damage has been a big problem in oilfield production. The current detection methods mostly are used after casing damage, which is not very effective. With the rapid development of China's offshore oil industry, the number of offshore oil wells is becoming larger and larger. Because the cost of offshore oil well is very high, the casing damage will cause huge economic losses. What's more, it can also bring serious pollution to marine environment. So the effective methods of detecting casing damage are required badly. The accumulation of stress is the main reason for the casing damage. Magnetic anisotropy technique based on counter magnetostriction effect can detect the stress of casing in real time and help us to find out the hidden dangers in time. It is essential for us to prevent the casing damage from occurring. However, such technique is still in the development stage. Previous studies mostly got the relationship between stress and magnetic signals by physical experiment, and the study of physical mechanism in relative magnetic permeability connecting the stress and magnetic signals is rarely reported. The present paper uses the ANSYS to do the three-dimensional finite element numerical simulation to study how the relative magnetic permeability works for the oil casing model. We find that the quantitative relationship between the stress' s variation and magnetic induction intensity's variation is: Δδ =K* ΔB, K = 8.04×109, which is proved correct by physical experiment.
基金Special and Significant Project of China National Petroleum Corporation for Shale Gas“On-site Tests of Drilling&Production Engineering for Shale Gas”(No.:2014F-4702-05).
文摘In the ChangningeWeiyuan national shale gas demonstration area,SW Sichuan Basin,the wellbore integrity damage occurs in some shale gas wells and has direct effect on the gas production rate of single shale gas horizontal well.After statistics analysis was performed on the problems related with wellbore integrity,such as casing damage,casing running difficulty and cement sheath blow-by,the multi-factor coupling casing stress calculation and evaluation mode laws established.Then study was conducted on the influential mechanism of multi-factor coupling(temperature effect,casing bending and axial pressure)on casing damage.The shale slip mechanism and its relationship with casing sheared formation were analyzed by using the MohreCoulomb criterion.Inversion analysis was performed on the main controlling factors of casing friction by using the developed casing hook load prediction and friction analysis software.And finally,based on the characteristics of shale gas horizontal wells,wellbore integrity control measures were proposed in terms of design and construction process,so as to improve the drilling quality(DQ).More specifically,shale gas well casing design calculation method and check standard were modified,well structure and full bore hole trajectory design were optimized,drilling quality was improved,cement properties were optimized and cement sealing integrity during fracturing process was checked.These research findings are significant in the design and management of future shale gas borehole integrity.
文摘Du 813 super-heavy oil reservoir has been comprehensively treated to solve the problems of high viscosity of crude oil, short steam injection period, high steam injection pressure and low reserve control degree. By deploying new wells, casing damage well treatment and steam huff and puff technology research, the existing problems in block development have been effectively solved, and the block output has been increased.
文摘The casing damage is a serious problem when the steam-injection method is applied in the oilfields. In this work, the commercial software ANSYS is used to predict the thermal expansion and the thermal stresses of casings in steam-injection wells under different conditions, including steam channeling, well shut-in and cavitation in cement ring. The results indicate that nearly no temperature change occurs in oil-layer areas 4.0 m-6.0 m away from the casing center. When steam channeling appears, the maximum Mises stress of both the casing and the cement ring occurs on the interior wall. During the shut-in operation, while the maximum thermal expansion ocurs within the temperature-transition area, the maximum thermal stress will be on the interior wall of casing, exceeding the thermo-elastic yield ultimate stress of N80 steel. Besides, the thermal stress is much higher than the elastic strain limit if certain amounts of cavitations appear in the cement ring. Based on the results, some preventive measures against casing damage are proposed, which are verified through the successful application of TP120TH casings during well completion in Liao＇he oilfield.
