This study presents a comprehensive mechanical analysis of P110S oil tubing subjected to thermal and chemical coupling effects,with particular attention to the presence of rectangular corrosion defects.Drawing on the ...This study presents a comprehensive mechanical analysis of P110S oil tubing subjected to thermal and chemical coupling effects,with particular attention to the presence of rectangular corrosion defects.Drawing on the material’s stress–strain constitutive behavior,thermal expansion coefficient,thermal conductivity,and electrochemical test data,the research incorporates geometric nonlinearities arising from large deformations induced by corrosion.A detailed three-dimensional finite element(FE)model of the corroded P110S tubing is developed to simulate its response under complex loading conditions.The proposed model is rigorously validated through full-scale burst experiments and analytical calculations based on theoretical formulations.Building upon this validation,the Extended Finite Element Method(XFEM)and a failure criterion grounded in damage evolution mechanics are applied to investigate the mechanical behavior of the tubing under the coupled influences of temperature,stress,and chemical corrosion.Special emphasis is placed on the role of rectangular corrosion features in determining failure mechanisms.To further elucidate the impact of multiple interacting parameters,a sensitivity analysis is performed by integrating grey correlation theory with simulation outcomes.Based on these findings,the study systematically explores the elastic–plastic deformation process,crack initiation and propagation behavior,and the burst failure response of tubing specimens with varying axial lengths and depths of corrosion.The proposed methodology provides a robust predictive framework for petroleum engineers to evaluate fracture pressure,diagnose failure modes,assess operational risks,and optimize production strategies.展开更多
As shale gas technology has advanced,the horizontal well fracturing model has seen widespread use,leading to substantial improvements in industrial gas output from shale gas wells.Nevertheless,a swift decline in the p...As shale gas technology has advanced,the horizontal well fracturing model has seen widespread use,leading to substantial improvements in industrial gas output from shale gas wells.Nevertheless,a swift decline in the productivity of individual wells remains a challenge that must be addressed throughout the development process.In this study,gas wells with two different wellbore trajectory structures are considered,and the OLGA software is exploited to perform transient calculations on various tubing depth models.The results can be articulated as follows.In terms of flow patterns:for the deep well A1(upward-buckled),slug flow occurs in the Kick-off Point position and above;for the deep well B1(downward-inclined),slug flow only occurs in the horizontal section.Wells with downward-inclined horizontal sections are more prone to liquid accumulation issues.In terms of comparison to conventional wells,it is shown that deep shale gas wells have longer normal production durations and experience liquid accumulation later than conventional wells.With regard to optimal tubing placement:for well A1(upward-buckled),it is recommended to place tubing at the Kick-off Point position;for well B1(downward-inclined),it is recommended to place tubing at the lower heel of the horizontal section.Finally,in terms of production performance:well A1(upward-buckled)outperforms well B1(downward-inclined)in terms of production and fluid accumulation.In particular,the deep well A1 is 1.94 times more productive and 1.3 times longer to produce than conventional wells.Deep well B1 is 1.87 times more productive and 1.34 times longer than conventional wells.展开更多
The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat...The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat-shrinkable tubing,as a seal on the rock surface,is crucial for reconstructing deep rock in situ conditions(ensuring the accuracy and effectiveness of confining pressure and pore pressure).However,there are few reports on testing such material under HTUP condition.Thus,the mechanical and sealing performances of existing heat-shrinkable tubing under HTUP condition is still immature.The motivation of this study is to advance deep rock mechanics and engineering by developing a polymer heat-shrinkable tubing(pressure larger than 140 MPa and temperature greater than 150℃).Experiments using the deep rock in situ thermal insulation coring test system were conducted and compared with conventional heat-shrinkable tubing.The sealing performance of the polymer heat-shrinkable tubing was investigated.The results indicated that deep rock ultrahigh-pressure condition and natural damage to the rock surface are the main causes of conventional heat-shrinkable tubing failure.In contrast,the damage rate of the proposed polymer heat-shrinkable tubing is extremely low,indicating that incorporating base material with high-performances can significantly enhance the pressure resistance of polymer heat-shrinkable tubing.Additionally,through the analysis of experimental results and the three-dimensional(3D)morphology of rock surfaces,the failure behavior of heat-shrinkable tubing under HTUP condition was revealed at the meso-structural level,and the proposed failure criteria,taking into account 3D morphology of rock surfaces and applicable to HTUP condition,have been advanced.The findings offer possibilities for triaxial rock mechanics testing in HTUP condition,providing theoretical and technical support for experiments and engineering applications in deep rock mechanics.展开更多
Corrosion failure of N80-Q tubing occurred in a gas well.The causes of corrosion failure were investigated through macroscopic morphology,corrosion product analysis,and microbial analysis.The results show that the cor...Corrosion failure of N80-Q tubing occurred in a gas well.The causes of corrosion failure were investigated through macroscopic morphology,corrosion product analysis,and microbial analysis.The results show that the corrosion patterns of N80-Q tubing were diverse.The failure resulted from the combined action of microbial corrosion,CO_(2)/Cl^(-) corrosion,and erosion corrosion.展开更多
L1 is one of the largest offshore gas fields currently under development.In order to optimize the related design,nodal analysis is applied(including proper consideration of the plant productivity,sensitivity to the tu...L1 is one of the largest offshore gas fields currently under development.In order to optimize the related design,nodal analysis is applied(including proper consideration of the plant productivity,sensitivity to the tubing size,erosion effects,liquid carrying performance,and tubing string).As a result of such approach,it is shown that 13Cr material should be chosen as the appropriate tubing material.Moreover,3-1/2 inches 9.3 lb/ft N80 tubing,4-1/2 inches 12.75 lb/ft N80 tubing,5-1/2 inches 17 lb/ft N80 tubing should be used for a gas production rate under 80×10^(4)m^(3)/d,between 80×10^(4)m^(3)/d and 120×10^(4)m^(3)/d and above 120×10^(4)m^(3)/d,respectively.展开更多
A shear ram is of great significance to ensuring the safe operation of oil/gas well drilling and production,but the mechanical properties of the ram itself in the shearing process are rarely researched.Based on the ba...A shear ram is of great significance to ensuring the safe operation of oil/gas well drilling and production,but the mechanical properties of the ram itself in the shearing process are rarely researched.Based on the basic motion law of the shear ram,combined its structural and operating parameters comprehensively,a model for solving the stress on the cutting edge was established corresponding to three stages(i.e.,shear point contact,cutting and penetrating the drill pipe)according to the wedge stress theory.Then,based on the novel shear ram,the numerical simulation and indoor shear experiment were carried out on CT90 coiled tubing to understand the variation laws of ram stress and shear point stress in the shearing process.And the following research results were obtained.First,when the shear point doesn't contact with the CT90 coiled tubing,the stress at the V-shaped angular center of the ram is the largest,and that at the shear point is extremely small.Second,when the shear point just touches the CT90 coiled tubing,the phenomenon of stress concentration occurs in the vicinity of the shear point of the ram cutting edge.Third,when the shear point cuts into the CT90 coiled tubing,the stress on the shear point and on both wedge edges is the largest,reaching the strength limit of the ram(1050MPa).Fourth,when the shear point enters the annulus after penetrating the CT90 coiled tubing,the ram stress on both sides of the junction between the cutting edge chamfer and the vertical plane is the largest.Fifth,After the CT90 coiled tubing is cut,crack damage occurs in the vicinity of the shear point of the ram cutting edge.In conclusion,the research results can better reflect the stress state of the ram cutting edge and its interaction with the drill pipe in the shearing process,and can provide an important reference for the design,manufacturing and the correct field application of shear rams.展开更多
Chinese utilities as well as those worldwide are facing increased demand for additional electricity, reduced plant emissions and greater efficiency. To meet this challenge will require increasing boiler temperature, p...Chinese utilities as well as those worldwide are facing increased demand for additional electricity, reduced plant emissions and greater efficiency. To meet this challenge will require increasing boiler temperature, pressure and coal ash corrosion resistance of the materials of boiler construction of future coal-fired boilers. A new nickel-based tube alloy, INCONEL^R alloy 740, is described aiming at meeting this challenge. Emphasis will be on describing the alloy＇ s mechanical properties, coal-ash and steam corrosion resistance. Microstructural stability as a function of temperature and time is addressed as well as some of the early methodology em- ployed to arrive at the current chemical composition.展开更多
To improve the rate of penetration(ROP) in drilling deep and hard formations, this paper proposes a new drilling method called coiled tubing partial underbalanced drilling(CT-PUBD). As a preliminary investigation into...To improve the rate of penetration(ROP) in drilling deep and hard formations, this paper proposes a new drilling method called coiled tubing partial underbalanced drilling(CT-PUBD). As a preliminary investigation into the new drilling method, this paper presents predictions of hole cleaning efficiency, drilling speed, cuttings migration and pressure loss in the drilling process with CT-PUBD. Based on numerical simulation and full-scale experimental studies, we conclude that using CT-PUBD, an underbalanced drilling condition can be achieved near the bit while maintaining wellbore safety at the same time. This condition can be achieved using a cuttings discharge device, a rotary packer and a backflow controller.According to the numerical simulations performed in this study, CT-PUBD can achieve high efficiency of hole cleaning.Along the cuttings migration process, the fluid velocities can reach the maximum values in the backflow holes. A full-scale laboratory experimental system was used to test the hydraulic characteristics and obtain the drilling performance of the new technology. The result shows that CT-PUBD significantly improves the ROP compared to the conventional drilling method.展开更多
Stress corrosion cracking （SCC） behavior of P 110 tubing steel in simulated C02 injection well annulus environments was investigated through three-point bent tests, potentiodynamic polarization and EIS measurements....Stress corrosion cracking （SCC） behavior of P 110 tubing steel in simulated C02 injection well annulus environments was investigated through three-point bent tests, potentiodynamic polarization and EIS measurements. The results demonstrate that SCC of P110 tubing steel could occur in acidulous simulated environment, and the sensitivity of SCC increases with the decrease ofpH, as well as increase of sulfide concentration and total environmental pressure. Both anodic dissolution and hydrogen embrittlement make contributions to the SCC. Adequate concentration of corrosion inhibitor can inhibit the occurrence of SCC on account of the inhibition of localized anodic dissolution and cathodic hydrogen evolution.展开更多
The tubing hanger is an important component of the subsea Christmas tree, experiencing big temperature difference which will lead to very high thermal stresses. On the basis of API 17D/ISO 13628-4 and ASME VIII-1, and...The tubing hanger is an important component of the subsea Christmas tree, experiencing big temperature difference which will lead to very high thermal stresses. On the basis of API 17D/ISO 13628-4 and ASME VIII-1, and by comprehensively considering the erosion of oil and the gravity load of the tubing, a calculation model is established by regarding design pressure and thermal stress, and the method for designing the tubing hanger of the horizontal Christmas tree under big temperature difference condition is developed from the fourth strength theory. The proposed theory for strength design of the tubing hanger in big temperature difference is verified by numerical results from ABAQUS.展开更多
Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and s...Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and sand-oil flow with high production in deviated tubing,solids deposition with water shows obvious non-symmetric distributions in deviated tubing from simulations and experiments.The mathematical model of two phase flow was developed under coupling conditions of deviated tubing,low flow rate and viscosity based on the kinetic theory of granular flow and first-order discrete scheme.The results show that solid-water stratified flow in deviated tubing can be divided into two zones of suspension bed and the moving bed throughout the flow field.The solid flowing velocity with water is negative and particles slide down at the bottom of moving bed zone.The process of solids flow with water in deviated tubing will produce pressure loss and consume the kinetic energy.The thickness of deposited layer and the flowing velocity of solids flow downward with water at the moving bed zone enhance with the decreased inlet flow rate and the increased particle size,tubing inside diameter(ID)and inclination angle.Solids are easier into suspension from the upper part of moving bed zone to suspension bed zone and more solid particles flow with water towards the tubing outlet with the increase of inlet flowing velocity.The decision is made to reduce the screen width,tubing ID and inclination angle to maintain to be greater than critical deposition velocity in order to prevent solids settling.And it provides the theoretical basis and technical reserves for solid control and offers an effective approach to enhance tubing cleaning in deviated strings.展开更多
AIM: To evaluate the long-term treatment outcomes in patients who underwent revision of external dacryocysto- rhinostomy (DCR) and nasal intubation by bicanalicular silicone tubing (BSTI) under endonasal endoscopic gu...AIM: To evaluate the long-term treatment outcomes in patients who underwent revision of external dacryocysto- rhinostomy (DCR) and nasal intubation by bicanalicular silicone tubing (BSTI) under endonasal endoscopic guidance. · METHODS: Data from 28 patients with recurrent dacryocystitis were retrospectively reviewed. Revision external DCR and bicanalicular nasal intubation by silicone tubing under endonasal endoscopic guidance was performed in 28 eyes of 28 patients. The patients were evaluated with respect to the reason of recurrence, time to recurrence, time to revision, duration of follow-up and surgical success. · RESULTS: Endoscopic endonasal examination detected an osteotomy-side obstruction by the excessive granulation tissue in 24 patients (86%), nasal septal deviation in three patients (10%) and nasal polyp in one patient (4%). Recurrence occurred after a mean duration of 5.3±3.7 months following the first operation. The mean time between the first DCR operation and the revision DCR was 11.5 ± 9.3 months. After a mean follow-up of 14.9±7.8 months, the rate of anatomic success alone was 85% (24/28); the rate of subjective success was 78% (22/28). · CONCLUSION: Revision external DCR and bicanalicular nasal intubation by silicone tubing under endonasal endoscopic guidance can be recommended in patients with recurrent dacryocystitis as a surgical approach that achieves satisfactory objective and subjective success rates.展开更多
BACKGROUND Transendoscopic enteral tubing(TET)has been used in China as a novel delivery route for fecal microbiota transplantation(FMT)into the whole colon with a high degree of patient satisfaction among adults.AIM ...BACKGROUND Transendoscopic enteral tubing(TET)has been used in China as a novel delivery route for fecal microbiota transplantation(FMT)into the whole colon with a high degree of patient satisfaction among adults.AIM To explore the recognition and attitudes of FMT through TET in patients with inflammatory bowel disease(IBD).METHODS An anonymous questionnaire,evaluating their awareness and attitudes toward FMT and TET was distributed among IBD patients in two provinces of Eastern and Southwestern China.Question formats included single-choice questions,multiple-choice questions and sorting questions.Patients who had not undergone FMT were mainly investigated for their cognition and acceptance of FMT and TET.Patients who had experience of FMT,the way they underwent FMT and acceptance of TET were the main interest.Then all the patients were asked whether they would recommend FMT and TET.This study also analyzed the preference of FMT delivery in IBD patients and the patient-related factors associated with it.RESULTS A total of 620 eligible questionnaires were included in the analysis.The survey showed that 44.6%(228/511)of patients did not know that FMT is a therapeutic option in IBD,and 80.6%(412/511)of them did not know the concept of TET.More than half(63.2%,323/511)of the participants stated that they would agree to undergo FMT through TET.Of the patients who underwent FMT via TET[62.4%(68/109)],the majority[95.6%(65/68)]of them were satisfied with TET.Patients who had undergone FMT and TET were more likely to recommend FMT than patients who had not(94.5%vs 86.3%,P=0.018 and 98.5%vs 87.8%,P=0.017).Patients’choice for the delivery way of FMT would be affected by the type of disease and whether the patient had the experience of FMT.When compared to patients without experience of FMT,Crohn’s disease and ulcerative colitis patients who had experience of FMT preferred mid-gut TET(P<0.001)and colonic TET(P<0.001),respectively.CONCLUSION Patients’experience of FMT through TET lead them to maintain a positive attitude towards FMT.The present findings highlighted the significance of patient education on FMT and TET.展开更多
The main failure modes of tubing and casing in current service conditions are represented in this study.The progress of the tubing and casing application technology and the problems that should be focused on during ap...The main failure modes of tubing and casing in current service conditions are represented in this study.The progress of the tubing and casing application technology and the problems that should be focused on during application are introduced,with special attention paid to the reliability of the pipe string design and the connection sealing properties.The necessary work that should be undertaken in future research is also summarized.展开更多
There are many problems associated with coiled tubing drilling operations, such as great circulation pressure loss inside pipe, difficulties in weight on bit(WOB) transferring, and high probability of differential sti...There are many problems associated with coiled tubing drilling operations, such as great circulation pressure loss inside pipe, difficulties in weight on bit(WOB) transferring, and high probability of differential sticking. Aiming at these problems, solids-free brine drilling fluid system was developed on the basis of formulation optimization with brine base fluid experiment, which was evaluated and applied to field drilling. Based on the optimization of flow pattern regulator, salt-resisting filtrate reducer, high performance lubricant and bit cleaner, the basic formula of the solids-free brine drilling fluid system was formed: brine +(0.1%-0.2%) Na OH +(0.2%-0.4%) HT-XC +(2.0%-3.0%) YLJ-1 +(0.5%-2.0%) SDNR +(1.0%-2.5%) FT-1 A +(1.0%-5.0%) SD-505 + compound salt density regulator. Lab evaluation showed that the fluid had satisfactory temperature resistance(up to 150 ℃), excellent cuttings tolerance(up to 25%), and strong inhibition(92.7% cuttings recovery); Moreover, its lubrication performance was similar to that of all oil-based drilling fluid. The wellbore could be fairly cleaned at annular up-flow velocity of more than 0.8 m/s if the ratio of yield point to plastic viscosity was kept above 0.5. This fluid system has been applied in the drilling of three coiled tubing sidetracking wells in the Liaohe Oilfield, during which the system was stable and easy to adjust, resulting in excellent cuttings transportation, high ROP, regular hole size, and no down hole accidents. In summary, the solids-free brine drilling fluid system can meet the technical requirements of coiled tubing drilling.展开更多
Due to the influence of multiple factors such as internal and external formation and mechanical pressure, medium corrosion and construction operation environment, a tubing collapse failure occurred in an oil well. In ...Due to the influence of multiple factors such as internal and external formation and mechanical pressure, medium corrosion and construction operation environment, a tubing collapse failure occurred in an oil well. In order to determine the failure cause of the tubing, physical and chemical tests and mechanical properties analysis were carried out on the failed tubing sample and the intact tubing. The results show that the chemical composition, ultrasonic and magnetic particle inspection, metallographic test, Charpy impact energy and external pressure mechanical property test of the failed tubing all meet the requirements of API Spec 5CT-2021 standard, but the yield strength of the failed tubing does not meet the requirements of API Spec 5CT-2021 standard. Through the analysis of the working conditions, it can be seen that the anti-extrusion strength of the tubing collapse does not meet the API 5C3 anti-extrusion strength standard. The failure type of the well tubing is tubing collapse caused by large internal and external pressure difference.展开更多
Salt caverns are extensively utilized for storing various substances such as fossil energy,hydrogen,compressed air,nuclear waste,and industrial solid waste.In China,when the salt cavern is leached through single-well ...Salt caverns are extensively utilized for storing various substances such as fossil energy,hydrogen,compressed air,nuclear waste,and industrial solid waste.In China,when the salt cavern is leached through single-well water solution mining with oil as a cushion,engineering challenges arise with the leaching tubing,leading to issues like damage and instability.These problems significantly hinder the progress of cavern construction and the control of cavern shape.The primary cause of this is the flowinduced vibration instability of leaching tubing within a confined space,which results in severe bending or damage to the tubing.This study presents a model experimental investigation on the dynamic characteristics of leaching tubing using a self-developed liquid-solid coupling physical model experiment apparatus.The experiment utilizes a silicone-rubber pipe(SRP)and a polycarbonate pipe(PCP)to examine the effects of various factors on the dynamic stability of cantilevered pipes conveying fluid.These factors include external space constraint,flexural rigidity,medium outside the pipe,overhanging length,and end conditions.The experiments reveal four dynamic response phenomena:water hammer,static buckling,chaotic motion,and flutter instability.The study further demonstrates that the length of the external space constraint has a direct impact on the flutter critical flow velocity of the cantilevered pipe conveying fluid.Additionally,the flutter critical flow velocity is influenced by the end conditions and different external media.展开更多
文摘This study presents a comprehensive mechanical analysis of P110S oil tubing subjected to thermal and chemical coupling effects,with particular attention to the presence of rectangular corrosion defects.Drawing on the material’s stress–strain constitutive behavior,thermal expansion coefficient,thermal conductivity,and electrochemical test data,the research incorporates geometric nonlinearities arising from large deformations induced by corrosion.A detailed three-dimensional finite element(FE)model of the corroded P110S tubing is developed to simulate its response under complex loading conditions.The proposed model is rigorously validated through full-scale burst experiments and analytical calculations based on theoretical formulations.Building upon this validation,the Extended Finite Element Method(XFEM)and a failure criterion grounded in damage evolution mechanics are applied to investigate the mechanical behavior of the tubing under the coupled influences of temperature,stress,and chemical corrosion.Special emphasis is placed on the role of rectangular corrosion features in determining failure mechanisms.To further elucidate the impact of multiple interacting parameters,a sensitivity analysis is performed by integrating grey correlation theory with simulation outcomes.Based on these findings,the study systematically explores the elastic–plastic deformation process,crack initiation and propagation behavior,and the burst failure response of tubing specimens with varying axial lengths and depths of corrosion.The proposed methodology provides a robust predictive framework for petroleum engineers to evaluate fracture pressure,diagnose failure modes,assess operational risks,and optimize production strategies.
文摘As shale gas technology has advanced,the horizontal well fracturing model has seen widespread use,leading to substantial improvements in industrial gas output from shale gas wells.Nevertheless,a swift decline in the productivity of individual wells remains a challenge that must be addressed throughout the development process.In this study,gas wells with two different wellbore trajectory structures are considered,and the OLGA software is exploited to perform transient calculations on various tubing depth models.The results can be articulated as follows.In terms of flow patterns:for the deep well A1(upward-buckled),slug flow occurs in the Kick-off Point position and above;for the deep well B1(downward-inclined),slug flow only occurs in the horizontal section.Wells with downward-inclined horizontal sections are more prone to liquid accumulation issues.In terms of comparison to conventional wells,it is shown that deep shale gas wells have longer normal production durations and experience liquid accumulation later than conventional wells.With regard to optimal tubing placement:for well A1(upward-buckled),it is recommended to place tubing at the Kick-off Point position;for well B1(downward-inclined),it is recommended to place tubing at the lower heel of the horizontal section.Finally,in terms of production performance:well A1(upward-buckled)outperforms well B1(downward-inclined)in terms of production and fluid accumulation.In particular,the deep well A1 is 1.94 times more productive and 1.3 times longer to produce than conventional wells.Deep well B1 is 1.87 times more productive and 1.34 times longer than conventional wells.
基金funding provided by the National Natural Science Foundation of China(Grant Nos.51827901 and 52174084)the Natural Science Foundation of Sichuan Provence,China(Grant No.2022NSFSC0005).
文摘The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat-shrinkable tubing,as a seal on the rock surface,is crucial for reconstructing deep rock in situ conditions(ensuring the accuracy and effectiveness of confining pressure and pore pressure).However,there are few reports on testing such material under HTUP condition.Thus,the mechanical and sealing performances of existing heat-shrinkable tubing under HTUP condition is still immature.The motivation of this study is to advance deep rock mechanics and engineering by developing a polymer heat-shrinkable tubing(pressure larger than 140 MPa and temperature greater than 150℃).Experiments using the deep rock in situ thermal insulation coring test system were conducted and compared with conventional heat-shrinkable tubing.The sealing performance of the polymer heat-shrinkable tubing was investigated.The results indicated that deep rock ultrahigh-pressure condition and natural damage to the rock surface are the main causes of conventional heat-shrinkable tubing failure.In contrast,the damage rate of the proposed polymer heat-shrinkable tubing is extremely low,indicating that incorporating base material with high-performances can significantly enhance the pressure resistance of polymer heat-shrinkable tubing.Additionally,through the analysis of experimental results and the three-dimensional(3D)morphology of rock surfaces,the failure behavior of heat-shrinkable tubing under HTUP condition was revealed at the meso-structural level,and the proposed failure criteria,taking into account 3D morphology of rock surfaces and applicable to HTUP condition,have been advanced.The findings offer possibilities for triaxial rock mechanics testing in HTUP condition,providing theoretical and technical support for experiments and engineering applications in deep rock mechanics.
文摘Corrosion failure of N80-Q tubing occurred in a gas well.The causes of corrosion failure were investigated through macroscopic morphology,corrosion product analysis,and microbial analysis.The results show that the corrosion patterns of N80-Q tubing were diverse.The failure resulted from the combined action of microbial corrosion,CO_(2)/Cl^(-) corrosion,and erosion corrosion.
基金supported by the National Natural Science Foundation of China(Grant No.52174015)the Scientific Research Project of CNOOC(China)Co.,Ltd.“Research on key technologies for drilling and completion of 20 million cubic meters in Western Nanhai Oilfield”(No.CNOOC-KJ135ZDXM38ZJ05ZJ).
文摘L1 is one of the largest offshore gas fields currently under development.In order to optimize the related design,nodal analysis is applied(including proper consideration of the plant productivity,sensitivity to the tubing size,erosion effects,liquid carrying performance,and tubing string).As a result of such approach,it is shown that 13Cr material should be chosen as the appropriate tubing material.Moreover,3-1/2 inches 9.3 lb/ft N80 tubing,4-1/2 inches 12.75 lb/ft N80 tubing,5-1/2 inches 17 lb/ft N80 tubing should be used for a gas production rate under 80×10^(4)m^(3)/d,between 80×10^(4)m^(3)/d and 120×10^(4)m^(3)/d and above 120×10^(4)m^(3)/d,respectively.
基金supported by the National Major Special Project of Oil and Gas(No.2016ZX05042003-001,2016ZX05066004-002)the Scientific and Technological Research Guidance Project(No.MTKJ2016-279)by the China National Coal Association,and the Jiangsu Provincial Postdoctoral Scientific and Technological Funding Program(No.1601053C).
文摘A shear ram is of great significance to ensuring the safe operation of oil/gas well drilling and production,but the mechanical properties of the ram itself in the shearing process are rarely researched.Based on the basic motion law of the shear ram,combined its structural and operating parameters comprehensively,a model for solving the stress on the cutting edge was established corresponding to three stages(i.e.,shear point contact,cutting and penetrating the drill pipe)according to the wedge stress theory.Then,based on the novel shear ram,the numerical simulation and indoor shear experiment were carried out on CT90 coiled tubing to understand the variation laws of ram stress and shear point stress in the shearing process.And the following research results were obtained.First,when the shear point doesn't contact with the CT90 coiled tubing,the stress at the V-shaped angular center of the ram is the largest,and that at the shear point is extremely small.Second,when the shear point just touches the CT90 coiled tubing,the phenomenon of stress concentration occurs in the vicinity of the shear point of the ram cutting edge.Third,when the shear point cuts into the CT90 coiled tubing,the stress on the shear point and on both wedge edges is the largest,reaching the strength limit of the ram(1050MPa).Fourth,when the shear point enters the annulus after penetrating the CT90 coiled tubing,the ram stress on both sides of the junction between the cutting edge chamfer and the vertical plane is the largest.Fifth,After the CT90 coiled tubing is cut,crack damage occurs in the vicinity of the shear point of the ram cutting edge.In conclusion,the research results can better reflect the stress state of the ram cutting edge and its interaction with the drill pipe in the shearing process,and can provide an important reference for the design,manufacturing and the correct field application of shear rams.
文摘Chinese utilities as well as those worldwide are facing increased demand for additional electricity, reduced plant emissions and greater efficiency. To meet this challenge will require increasing boiler temperature, pressure and coal ash corrosion resistance of the materials of boiler construction of future coal-fired boilers. A new nickel-based tube alloy, INCONEL^R alloy 740, is described aiming at meeting this challenge. Emphasis will be on describing the alloy＇ s mechanical properties, coal-ash and steam corrosion resistance. Microstructural stability as a function of temperature and time is addressed as well as some of the early methodology em- ployed to arrive at the current chemical composition.
基金the National Natural Science Foundation of China (Grant No. 51474232)the National Science and Technology Major Project (Grant No. 2016ZX05022)
文摘To improve the rate of penetration(ROP) in drilling deep and hard formations, this paper proposes a new drilling method called coiled tubing partial underbalanced drilling(CT-PUBD). As a preliminary investigation into the new drilling method, this paper presents predictions of hole cleaning efficiency, drilling speed, cuttings migration and pressure loss in the drilling process with CT-PUBD. Based on numerical simulation and full-scale experimental studies, we conclude that using CT-PUBD, an underbalanced drilling condition can be achieved near the bit while maintaining wellbore safety at the same time. This condition can be achieved using a cuttings discharge device, a rotary packer and a backflow controller.According to the numerical simulations performed in this study, CT-PUBD can achieve high efficiency of hole cleaning.Along the cuttings migration process, the fluid velocities can reach the maximum values in the backflow holes. A full-scale laboratory experimental system was used to test the hydraulic characteristics and obtain the drilling performance of the new technology. The result shows that CT-PUBD significantly improves the ROP compared to the conventional drilling method.
基金Project(2012AA040105)supported by the High-tech Research and Development Program of ChinaProject(2014CB643300)supported by National Basic Research Program of ChinaProject(51741034)supported by National Natural Science Foundation of China
文摘Stress corrosion cracking （SCC） behavior of P 110 tubing steel in simulated C02 injection well annulus environments was investigated through three-point bent tests, potentiodynamic polarization and EIS measurements. The results demonstrate that SCC of P110 tubing steel could occur in acidulous simulated environment, and the sensitivity of SCC increases with the decrease ofpH, as well as increase of sulfide concentration and total environmental pressure. Both anodic dissolution and hydrogen embrittlement make contributions to the SCC. Adequate concentration of corrosion inhibitor can inhibit the occurrence of SCC on account of the inhibition of localized anodic dissolution and cathodic hydrogen evolution.
基金financially supported by the National Science and Technology Major Project of China(Grant No.2011ZX05026-003-02)the National High Technology Research and Development Program of China(863 Program,Grant No.2012AA09A205)
文摘The tubing hanger is an important component of the subsea Christmas tree, experiencing big temperature difference which will lead to very high thermal stresses. On the basis of API 17D/ISO 13628-4 and ASME VIII-1, and by comprehensively considering the erosion of oil and the gravity load of the tubing, a calculation model is established by regarding design pressure and thermal stress, and the method for designing the tubing hanger of the horizontal Christmas tree under big temperature difference condition is developed from the fourth strength theory. The proposed theory for strength design of the tubing hanger in big temperature difference is verified by numerical results from ABAQUS.
基金funded by National Natural Science Foundation of China(Grant No.52074161)National Science and Technology Major Project of China(Grant No.2016ZX05065-001)+2 种基金Taishan Scholar Project of Shandong Province(Grant No.tsqn202211177)Shandong Provincial Plan for Introduction and Cultivation of Young Pioneers in Colleges and Universities(Grant No.2021-QingChuang-30613019)Natural Science Foundation of Shandong Province(Grant No.ZR2022ME173).
文摘Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and sand-oil flow with high production in deviated tubing,solids deposition with water shows obvious non-symmetric distributions in deviated tubing from simulations and experiments.The mathematical model of two phase flow was developed under coupling conditions of deviated tubing,low flow rate and viscosity based on the kinetic theory of granular flow and first-order discrete scheme.The results show that solid-water stratified flow in deviated tubing can be divided into two zones of suspension bed and the moving bed throughout the flow field.The solid flowing velocity with water is negative and particles slide down at the bottom of moving bed zone.The process of solids flow with water in deviated tubing will produce pressure loss and consume the kinetic energy.The thickness of deposited layer and the flowing velocity of solids flow downward with water at the moving bed zone enhance with the decreased inlet flow rate and the increased particle size,tubing inside diameter(ID)and inclination angle.Solids are easier into suspension from the upper part of moving bed zone to suspension bed zone and more solid particles flow with water towards the tubing outlet with the increase of inlet flowing velocity.The decision is made to reduce the screen width,tubing ID and inclination angle to maintain to be greater than critical deposition velocity in order to prevent solids settling.And it provides the theoretical basis and technical reserves for solid control and offers an effective approach to enhance tubing cleaning in deviated strings.
文摘AIM: To evaluate the long-term treatment outcomes in patients who underwent revision of external dacryocysto- rhinostomy (DCR) and nasal intubation by bicanalicular silicone tubing (BSTI) under endonasal endoscopic guidance. · METHODS: Data from 28 patients with recurrent dacryocystitis were retrospectively reviewed. Revision external DCR and bicanalicular nasal intubation by silicone tubing under endonasal endoscopic guidance was performed in 28 eyes of 28 patients. The patients were evaluated with respect to the reason of recurrence, time to recurrence, time to revision, duration of follow-up and surgical success. · RESULTS: Endoscopic endonasal examination detected an osteotomy-side obstruction by the excessive granulation tissue in 24 patients (86%), nasal septal deviation in three patients (10%) and nasal polyp in one patient (4%). Recurrence occurred after a mean duration of 5.3±3.7 months following the first operation. The mean time between the first DCR operation and the revision DCR was 11.5 ± 9.3 months. After a mean follow-up of 14.9±7.8 months, the rate of anatomic success alone was 85% (24/28); the rate of subjective success was 78% (22/28). · CONCLUSION: Revision external DCR and bicanalicular nasal intubation by silicone tubing under endonasal endoscopic guidance can be recommended in patients with recurrent dacryocystitis as a surgical approach that achieves satisfactory objective and subjective success rates.
基金Jiangsu Province Creation Team and Leading Talents Project (to Zhang FM)。
文摘BACKGROUND Transendoscopic enteral tubing(TET)has been used in China as a novel delivery route for fecal microbiota transplantation(FMT)into the whole colon with a high degree of patient satisfaction among adults.AIM To explore the recognition and attitudes of FMT through TET in patients with inflammatory bowel disease(IBD).METHODS An anonymous questionnaire,evaluating their awareness and attitudes toward FMT and TET was distributed among IBD patients in two provinces of Eastern and Southwestern China.Question formats included single-choice questions,multiple-choice questions and sorting questions.Patients who had not undergone FMT were mainly investigated for their cognition and acceptance of FMT and TET.Patients who had experience of FMT,the way they underwent FMT and acceptance of TET were the main interest.Then all the patients were asked whether they would recommend FMT and TET.This study also analyzed the preference of FMT delivery in IBD patients and the patient-related factors associated with it.RESULTS A total of 620 eligible questionnaires were included in the analysis.The survey showed that 44.6%(228/511)of patients did not know that FMT is a therapeutic option in IBD,and 80.6%(412/511)of them did not know the concept of TET.More than half(63.2%,323/511)of the participants stated that they would agree to undergo FMT through TET.Of the patients who underwent FMT via TET[62.4%(68/109)],the majority[95.6%(65/68)]of them were satisfied with TET.Patients who had undergone FMT and TET were more likely to recommend FMT than patients who had not(94.5%vs 86.3%,P=0.018 and 98.5%vs 87.8%,P=0.017).Patients’choice for the delivery way of FMT would be affected by the type of disease and whether the patient had the experience of FMT.When compared to patients without experience of FMT,Crohn’s disease and ulcerative colitis patients who had experience of FMT preferred mid-gut TET(P<0.001)and colonic TET(P<0.001),respectively.CONCLUSION Patients’experience of FMT through TET lead them to maintain a positive attitude towards FMT.The present findings highlighted the significance of patient education on FMT and TET.
文摘The main failure modes of tubing and casing in current service conditions are represented in this study.The progress of the tubing and casing application technology and the problems that should be focused on during application are introduced,with special attention paid to the reliability of the pipe string design and the connection sealing properties.The necessary work that should be undertaken in future research is also summarized.
基金Supported by the China National Science and Technology Major Project(2016ZX05020-004)
文摘There are many problems associated with coiled tubing drilling operations, such as great circulation pressure loss inside pipe, difficulties in weight on bit(WOB) transferring, and high probability of differential sticking. Aiming at these problems, solids-free brine drilling fluid system was developed on the basis of formulation optimization with brine base fluid experiment, which was evaluated and applied to field drilling. Based on the optimization of flow pattern regulator, salt-resisting filtrate reducer, high performance lubricant and bit cleaner, the basic formula of the solids-free brine drilling fluid system was formed: brine +(0.1%-0.2%) Na OH +(0.2%-0.4%) HT-XC +(2.0%-3.0%) YLJ-1 +(0.5%-2.0%) SDNR +(1.0%-2.5%) FT-1 A +(1.0%-5.0%) SD-505 + compound salt density regulator. Lab evaluation showed that the fluid had satisfactory temperature resistance(up to 150 ℃), excellent cuttings tolerance(up to 25%), and strong inhibition(92.7% cuttings recovery); Moreover, its lubrication performance was similar to that of all oil-based drilling fluid. The wellbore could be fairly cleaned at annular up-flow velocity of more than 0.8 m/s if the ratio of yield point to plastic viscosity was kept above 0.5. This fluid system has been applied in the drilling of three coiled tubing sidetracking wells in the Liaohe Oilfield, during which the system was stable and easy to adjust, resulting in excellent cuttings transportation, high ROP, regular hole size, and no down hole accidents. In summary, the solids-free brine drilling fluid system can meet the technical requirements of coiled tubing drilling.
文摘Due to the influence of multiple factors such as internal and external formation and mechanical pressure, medium corrosion and construction operation environment, a tubing collapse failure occurred in an oil well. In order to determine the failure cause of the tubing, physical and chemical tests and mechanical properties analysis were carried out on the failed tubing sample and the intact tubing. The results show that the chemical composition, ultrasonic and magnetic particle inspection, metallographic test, Charpy impact energy and external pressure mechanical property test of the failed tubing all meet the requirements of API Spec 5CT-2021 standard, but the yield strength of the failed tubing does not meet the requirements of API Spec 5CT-2021 standard. Through the analysis of the working conditions, it can be seen that the anti-extrusion strength of the tubing collapse does not meet the API 5C3 anti-extrusion strength standard. The failure type of the well tubing is tubing collapse caused by large internal and external pressure difference.
基金financial support received from the Open Research Fund of the State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences (Grant No.Z019011)the Shandong Provincial Natural Science Foundation (Grant No.ZR2020QE112)+1 种基金the National Natural Science Foundation of China (No.51874273)the Excellent Young Scientists Fund Program of National Natural Science Foundation of China (No.52122403)。
文摘Salt caverns are extensively utilized for storing various substances such as fossil energy,hydrogen,compressed air,nuclear waste,and industrial solid waste.In China,when the salt cavern is leached through single-well water solution mining with oil as a cushion,engineering challenges arise with the leaching tubing,leading to issues like damage and instability.These problems significantly hinder the progress of cavern construction and the control of cavern shape.The primary cause of this is the flowinduced vibration instability of leaching tubing within a confined space,which results in severe bending or damage to the tubing.This study presents a model experimental investigation on the dynamic characteristics of leaching tubing using a self-developed liquid-solid coupling physical model experiment apparatus.The experiment utilizes a silicone-rubber pipe(SRP)and a polycarbonate pipe(PCP)to examine the effects of various factors on the dynamic stability of cantilevered pipes conveying fluid.These factors include external space constraint,flexural rigidity,medium outside the pipe,overhanging length,and end conditions.The experiments reveal four dynamic response phenomena:water hammer,static buckling,chaotic motion,and flutter instability.The study further demonstrates that the length of the external space constraint has a direct impact on the flutter critical flow velocity of the cantilevered pipe conveying fluid.Additionally,the flutter critical flow velocity is influenced by the end conditions and different external media.
