The study considers gas compression properties,gas slippage,back pressure(BP),phase transition(PT),well depth,and differences in gas-liquid physical properties.A new temperature model for multiphase flow is proposed b...The study considers gas compression properties,gas slippage,back pressure(BP),phase transition(PT),well depth,and differences in gas-liquid physical properties.A new temperature model for multiphase flow is proposed by considering phase transition in the drilling process.The mathematical model of multiphase flow is solved using the finite difference method with annulus mesh division for grid nodes,and a module for multiphase flow calculation and analysis is developed.Numerical results indicate that the temperature varies along the annulus with the variation of gas influx at the bottom of the well.During the process of controlled pressure drilling,as gas slips along the annulus to the wellhead,its volume continuously expands,leading to an increase in the gas content within the annulus,and consequently,an increase in the pressure drop caused by gas slippage.The temperature increases with the increase in BP and decreases in gas influx rate and wellbore diameter.During gas influx,the thermal conductivity coefficient for the gas-drilling mud two phases is significantly weakened,resulting in a considerable change in temperature along the annulus.In the context of MPD,the method of slightly changing the temperature along the annulus by controlling the back pressure is feasible.展开更多
Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydra...Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydration.An infrared spectral method and a thermogravimetric technique were used to characterize the chemical composition of the HLMP and evaluate its heat stability.Experiments were conducted to measure the linear swelling,rolling recovery rate,and bentonite inhibition rate and evaluate accordingly the inhibition performance of the HLMP.Moreover,the HLMP was characterized through measurements of the zeta potential,particle size distribution,contact angles,and interlayer space testing.As confirmed by the results,the HLMP could successfully be synthesized with a favorable heat stability.Furthermore,favorable results were found for the inhibitory processes of the HLMP on swelling and dispersed hydration during mud shale hydration.The positively charged HLMP could be electrically neutralized with clay particles,thereby inhibiting diffusion in the double electron clay layers.The hydrophobic group in the HLMP molecular structure resulted in the formation of a hydrophobic membrane on the rock surface,enhancing the hydrophobicity of the rock.In addition,the small molecules of the HLMP could plug the spaces between the layers of bentonite crystals,thereby reducing the entry of water molecules and inhibiting shale hydration.展开更多
High-temperature thin-film thermocouples(TFTCs)have attracted significant attention in the aerospace and steel metallurgy industry.However,previous studies on TFTCs have primarily focused on the two-dimensional planar...High-temperature thin-film thermocouples(TFTCs)have attracted significant attention in the aerospace and steel metallurgy industry.However,previous studies on TFTCs have primarily focused on the two-dimensional planar-type,whose thermal sensitive area has to be perpendicular to the test environment,and therefore affects the thermal fluids pattern or loses accuracy.In order to address this problem,recent studies have developed three-dimensional probe-type TFTCs,which can be set parallel to the test environment.Nevertheless,the probe-type TFTCs are limited by their measurement threshold and poor stability at high temperatures.To address these issues,in this study,we propose a novel probe-type TFTC with a sandwich structure.The sensitive layer is compounded with indium oxide doped zinc oxide and fabricated using screen-printing technology.With the protection of sandwich structure on electrode film,the sensor demonstrates robust high-temperature stability,enabling continuous working at 1200℃ above 5 h with a low drift rate of 2.3℃·h^(−1).This sensor exhibits a high repeatability of 99.3% when measuring a wide range of temperatures,which is beyond the most existing probe-type TFTCs reported in the literature.With its excellent high-temperature performance,this temperature sensor holds immense potentials for enhancing equipment safety in the aerospace engineering and ensuring product quality in the steel metallurgy industry.展开更多
The research progress of deep and ultra-deep drilling fluid technology systematically reviewed,the key problems existing are analyzed,and the future development direction is proposed.In view of the high temperature,hi...The research progress of deep and ultra-deep drilling fluid technology systematically reviewed,the key problems existing are analyzed,and the future development direction is proposed.In view of the high temperature,high pressure and high stress,fracture development,wellbore instability,drilling fluid lost circulation and other problems faced in the process of deep and ultra-deep complex oil and gas drilling,scholars have developed deep and ultra-deep high-temperature and high-salt resistant water-based drilling fluid technology,high-temperature resistant oil-based/synthetic drilling fluid technology,drilling fluid technology for reservoir protection and drilling fluid lost circulation control technology.However,there are still some key problems such as insufficient resistance to high temperature,high pressure and high stress,wellbore instability and serious lost circulation.Therefore,the development direction of deep and ultra-deep drilling fluid technology in the future is proposed:(1)The technology of high-temperature and high-salt resistant water-based drilling fluid should focus on improving high temperature stability,improving rheological properties,strengthening filtration control and improving compatibility with formation.(2)The technology of oil-based/synthetic drilling fluid resistant to high temperature should further study in the aspects of easily degradable environmental protection additives with low toxicity such as high temperature stabilizer,rheological regulator and related supporting technologies.(3)The drilling fluid technology for reservoir protection should be devoted to the development of new high-performance additives and materials,and further improve the real-time monitoring technology by introducing advanced sensor networks and artificial intelligence algorithms.(4)The lost circulation control of drilling fluid should pay more attention to the integration and application of intelligent technology,the research and application of high-performance plugging materials,the exploration of diversified plugging techniques and methods,and the improvement of environmental protection and production safety awareness.展开更多
Multi-gradient drilling is a new offshore drilling method.The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise cont...Multi-gradient drilling is a new offshore drilling method.The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore pressure.In this study,a new heat transfer model is proposed by which the variable mass flow is properly taken into account.Using this model,the effects of the main factors influencing the wellbore temperature are analyzed.The results indicate that at the position where the separation injection device is installed,the temperature increase of the fluid in the drill pipe is mitigated due to the inflow/outflow of hollow spheres,and the temperature drop of the fluid in the annulus also decreases.In addition,a lower separation efficiency of the device,a shallower installation depth and a smaller circulating displacement tend to increase the temperature near the bottom of the annulus,thereby helping to reduce the hydrate generation area and playing a positive role in the prevention and control of hydrates in deepwater drilling.展开更多
Many researches on drilling force and temperature have been done with the aim to reduce the labour intensiveness of surgery, avoid unnecessary damage and improve drilling quality. However, there has not been a systema...Many researches on drilling force and temperature have been done with the aim to reduce the labour intensiveness of surgery, avoid unnecessary damage and improve drilling quality. However, there has not been a systematic study of mid- and high-speed drilling under dry and physiological conditions（injection of saline）. Furthermore, there is no consensus on optimal drilling parameters. To study these parameters under dry and physiological drilling conditions, pig humerus bones are drilled with medical twist drills operated using a wide range of drilling speeds and feed rates. Drilling force and temperature are measured using a YDZ-II01W dynamometer and a NEC TVS-500EX thermal infrared imager, respectively, to evaluate internal bone damage. To evaluate drilling quality, bone debris and hole morphology are observed by SEM（scanning electron microscopy）. Changes in drilling force and temperature give similar results during drilling such that the value of each parameter peaks just before the drill penetrates through the osteon of the compact bone into the trabeculae of the spongy bone. Drilling temperatures under physiological conditions are much lower than those observed under dry conditions, while a larger drilling force occurs under physiological conditions than dry conditions. Drilling speed and feed rate have a significant influence on drilling force, temperature, bone debris and hole morphology. The investigation of the effect of drilling force and temperature on internal bone damage reveals that a drilling speed of 4500 r/min and a feed rate of 50 mm/min are recommended for bone drilling under physiological conditions. Drilling quality peaks under these optimal parameter conditions. This paper proposes the optimal drilling parameters under mid- and high-speed surgical drilling, considering internal bone damage and drilling quality, which can be looked as a reference for surgeons performing orthopedic operations.展开更多
To maintain tight control over rheological properties of high-density water-based drilling fluids, it is essential to understand the factors influencing the theology of water-based drilling fluids. This paper examines...To maintain tight control over rheological properties of high-density water-based drilling fluids, it is essential to understand the factors influencing the theology of water-based drilling fluids. This paper examines temperature effects on the rheological properties of two types of high-density water-based drilling fluids （fresh water-based and brine-based） under high temperature and high pressure （HTHP） with a Fann 50SL rheometer. On the basis of the water-based drilling fluid systems formulated in laboratory, this paper mainly describes the influences of different types and concentration of clay, the content of a colloid stabilizer named GHJ-1 and fluid density on the rheological parameters such as viscosity and shear stress. In addition, the effects of aging temperature and aging time of the drilling fluid on these parameters were also examined. Clay content and proportions for different densities of brine-based fluids were recommended to effectively regulate the rheological properties. Four theological models, the Bingham, power law, Casson and H-B models, were employed to fit the rheological parameters. It turns out that the H-B model was the best one to describe the rheological properties of the high-density drilling fluid under HTHP conditions and power law model produced the worst fit. In addition, a new mathematical model that describes the apparent viscosity as a function of temperature and pressure was established and has been applied on site.展开更多
The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental ...The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental results show that the apparent viscosity,plastic viscosity and yield point decrease with the increase of temperature,and increase with the increase of pressure.The effect of pressure on the apparent viscosity,plastic viscosity and yield point is considerable at ambient temperature.However,this effect gradually reduces with the increase of temperature.The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells.On the basis of numerous experiments,the model for predict the apparent viscosity,plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis.It is confirmed that the calculated data are in good agreement with the measured data,and the correlation coefficients are more than 0.98.The model is convenient for use and suitable for the application in drilling operations.展开更多
Temperature curves reflect geothermal gradients and local temperature anomalies, thus providing a new understanding of the underground reservoir conditions. When encountering caverns or fractures and fissures during d...Temperature curves reflect geothermal gradients and local temperature anomalies, thus providing a new understanding of the underground reservoir conditions. When encountering caverns or fractures and fissures during drilling, lost circulation may occur and result in a change to the original formation temperature field, and in severe cases, even the conventional open hole well logging data cannot be obtained. This paper uses finite element analysis software COMSOL to establish a heat transfer model for the wellbore/reservoir formation system during drilling and shut-in in the presence of lost circulation, and a case study is made in a carbonate reservoir in the Tahe oilfield. On the basis of the above, we analyze the temperature distribution in the leakage zone, and the studies have shown that the leakage and petrophysical properties have an impact on the temperature of the wellbore and formation, hence we can estimate the reservoir permeability using the temperature data. In addition, the determination of the temperature recovery time after some drilling fluids have leaked into the formation will help in recognizing the subsurface temperature field of the carbonate formation correctly, thus enhancing production logging interpretation accuracy and improving the understanding of later measurements.展开更多
The phenomenon of heat accumulation and transportation in the composite materials is a very typical and critical issue during drilling process.In this study,a three-dimensional temperature field prediction model is pr...The phenomenon of heat accumulation and transportation in the composite materials is a very typical and critical issue during drilling process.In this study,a three-dimensional temperature field prediction model is proposed using finite difference method,based on the partly homogenization hypothesis of material,to predict temperature field in the process of drilling unidirectional carbon fiber/epoxy(C/E)composites.According to the drilling feed motion,drilling process is divided into four stages to study the temperature distributing characteristics.The results show that the temperature distribution predicted by numerical study has a good agreement with the experimental results.The temperature increases with increasing the drilling depth,and the burn phenomena is observed due to the heat accumulation,especially at the drill exit.Due to the fiber orientation,an elliptical shape of the temperature field along the direction is found for both numerical and experimental studies of C/E composites drilling process.展开更多
Drilling fluids face failure during drilling deep reservoir with high temperature and high salt.The experimental results show that high temperature and salinity reduce the negative charge on the surface of bentonite i...Drilling fluids face failure during drilling deep reservoir with high temperature and high salt.The experimental results show that high temperature and salinity reduce the negative charge on the surface of bentonite in the drilling fluid and cause the coalescence of bentonite particles.As a result,the particles coalesce,the grid structure is destroyed,and the rheological properties,rock-carrying capacity and filtration properties are lost.To resolve the foregoing,in this study,0.05-wt%carbon nanotubes are introduced into a 4%bentonite drilling fluid under conditions where the temperature and concentration of added Na Cl reach 180°C and 10 wt%,respectively.The carbon nanotubes adsorb on the bentonite surface and increase the space among bentonite particles.The steric hindrance prevents the coalescence of bentonite in high temperature and high salt environment.Thus bentonite maintains the small size distribution of bentonite and supports the bentonite grid structure in the drilling fluid.As a result,the rock-carrying capacity of the drilling fluid increases by 85.1%.Moreover,the mud cake formed by the accumulation of small-sized bentonite particles is dense;consequently,the filtration of bentonite drilling fluid reduced by 30.2%.展开更多
With the rapid development of deepwater drilling operations,more and more complex technical challenges have to be faced due to the rigorous conditions encountered.One of these challenges is that the drilling fluid use...With the rapid development of deepwater drilling operations,more and more complex technical challenges have to be faced due to the rigorous conditions encountered.One of these challenges is that the drilling fluid used must had good rheological properties at low temperatures and high ability to inhibit hydrate formation.Synthetic drilling fluid has been widely applied to deepwater drilling operations due to its high penetration rate,excellent rheological properties,good ability to prevent hydrate formation,and high biodegradability.A synthetic drilling fluid formulation was developed in our laboratory.The rheological properties of this drilling fluid at low temperatures （0-20 °C） were tested with a 6-speed viscometer and its ability to inhibit hydrate formation was evaluated at 20 MPa CH 4 gas and 0 °C by differential scanning calorimetry （DSC）.Several factors influencing the low temperature rheological properties of this synthetic drilling fluid were studied in this paper.These included the viscosity of the base fluid,the amount of CEMU and organic clay,and the water volume fraction.展开更多
Drilling is regarded as the most complex manufacturing process compared with other conventional machining processes.During the drilling process,most of the energy consumed in metal cutting is converted to heat and inc...Drilling is regarded as the most complex manufacturing process compared with other conventional machining processes.During the drilling process,most of the energy consumed in metal cutting is converted to heat and increases temperature considerably.The resulting thermal phenomena are important since they influence the mode of deformation,the final metallurgical state of the machined surface,and the rate of tool wear.Hence,understanding the temperature characteristics in the drilling process is crucial for enhancing the drill performance and process efficiency.Extensive efforts have been conducted to measure and control the drilling tool temperature successively.However,very few studies have been conducted from a comprehensive perspective to review all the efforts.To address this gap in the literature,a rigorous review concerning the state-of-the-art results and advances in drilling tool temperature is presented in this paper by referring to the wide comparisons among literature analyses.The multiple aspects of drilling tool temperature are precisely detailed and discussed in terms of theoretical analysis and thermal modeling,methods for temperature measuring,the effect of cutting parameters,tool geometries and hole-making methods on temperature and temperature controlling by different cooling methods.In conclusion,several possible future research directions are discussed to offer potential insights for the drilling community and future researchers.展开更多
The working conditions of the MK-3 type full hydraulic tunnel drilling machine during the course of drilling were analyzed. Based on the energy balance governing equations for the drill rod, the temperature field of d...The working conditions of the MK-3 type full hydraulic tunnel drilling machine during the course of drilling were analyzed. Based on the energy balance governing equations for the drill rod, the temperature field of drill rod at the normal and non-normal working conditions was numerically obtained. The numerical results show that the maximum temperature at the head of drill rod under the normal working circumstance is insufficient to ignite the gas. But under the non-normal working condition, the local high temperature can ignite the gas easily and cause the fire. In order to prevent the gas fire, the occurrence of the non-normal operating condition must be prevented as far as possible during the drilling.展开更多
Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle（B4C） reinforced metal matrix composites（MMCs） with different drills. The effect of particle content, ...Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle（B4C） reinforced metal matrix composites（MMCs） with different drills. The effect of particle content, cutting speed, feed rate and tool material on the maximum drilling temperature was investigated. The drilling parameters were optimized based on multiple performance characteristics in terms of the maximum cutting temperature and tool wear. According to the results, the most influential control factors on the cutting temperatures are found to be particle fraction, feed rate and interaction between the cutting speed and particle content, respectively. The influences of the cutting speed and drill material on the drilling temperature are found to be relatively lower for the used range of parameters. Minimum cutting temperatures are obtained with lower particle fraction and cutting speed, with relatively higher feed rates and carbide tools. The results reveal that optimal combination of the drilling parameters can be used to obtain both minimum cutting temperature and tool wear.展开更多
Decreasing the risks and geohazards associated with drilling engineering in high-temperature high-pressure(HTHP) geologic settings begins with the implementation of pre-drilling prediction techniques(PPTs). To improve...Decreasing the risks and geohazards associated with drilling engineering in high-temperature high-pressure(HTHP) geologic settings begins with the implementation of pre-drilling prediction techniques(PPTs). To improve the accuracy of geopressure prediction in HTHP hydrocarbon reservoirs offshore Hainan Island, we made a comprehensive summary of current PPTs to identify existing problems and challenges by analyzing the global distribution of HTHP hydrocarbon reservoirs, the research status of PPTs, and the geologic setting and its HTHP formation mechanism. Our research results indicate that the HTHP formation mechanism in the study area is caused by multiple factors, including rapid loading, diapir intrusions, hydrocarbon generation, and the thermal expansion of pore fluids. Due to this multi-factor interaction, a cloud of HTHP hydrocarbon reservoirs has developed in the Ying-Qiong Basin, but only traditional PPTs have been implemented, based on the assumption of conditions that do not conform to the actual geologic environment, e.g., Bellotti's law and Eaton's law. In this paper, we focus on these issues, identify some challenges and solutions, and call for further PPT research to address the drawbacks of previous works and meet the challenges associated with the deepwater technology gap. In this way, we hope to contribute to the improved accuracy of geopressure prediction prior to drilling and provide support for future HTHP drilling offshore Hainan Island.展开更多
The Qaidam Basin in the NE Tibetan Plateau has contributed the largest amount of potash in China.However,how the potash was formed has long been a subject of debate.Here we carried out a deep drilling
The wellbore temperature has an important effect on design and drilling of deep well.<b> </b>Based on energy conservation equations and actual drilling data of one deep well, the wellbore temperature distr...The wellbore temperature has an important effect on design and drilling of deep well.<b> </b>Based on energy conservation equations and actual drilling data of one deep well, the wellbore temperature distribution was simulated and the influence of different parameters on the wellbore temperature was revealed <span>using the software of Hydraulics Analysis System. The results show that,</span> while drilling, the mud temperature in wellbore gradually decreases from the formation temperature to the stable temperature, and it is higher than the mud <span>inlet temperature on ground, the annular temperature is higher than the </span>temperature in drill string, and the bottom hole temperature is higher than the ground temperature. The effect of geothermal gradient on wellbore temperature is great, while the mud density is negligible. The bottom hole temperature increases with the increase of mud inlet temperature, geothermal gradient, mud thermal conductivity and decrease of mud flow rate, mud specific heat and mud density.展开更多
Combined with the current research status in this area at home and abroad, with the improvement of salt and high temperature resistance as the research goal, the laboratory research of salt and high temperature resist...Combined with the current research status in this area at home and abroad, with the improvement of salt and high temperature resistance as the research goal, the laboratory research of salt and high temperature resistant drilling fluid system has been carried out, and lubricants, inhibitors and stabilizers have been optimized. The final drilling fluid formula is: water + 3% sepiolite + 0.3% Na<sub>2</sub>CO<sub>3</sub> + 3% RH-225 + 3% KCOOH + 3% G-SPH + 3% CQA-10 + 1.5% ZX-1 + Xinjiang barite, density 2.2 g/cm<sup>3</sup>, using hot-rolling furnace, environmental scanning electron microscope, high temperature and high pressure plugging instrument and Zeiss microscopes and other instruments use core immersion experiments, permeability recovery value experiments, and static stratification index methods to perform temperature resistance, reservoir protection, plugging performance, and static settlement stability performance of the configured drilling fluid., Inhibition performance, biological toxicity, salt resistance, anti-pollution performance have been tested, and it is concluded that the temperature resistance is good under the condition of 210°C, and the salt resistance can meet the requirements of 20% NaCl + 0.5% CaCl<sub>2</sub> concentration. It has a good reservoir protection effect, the permeability recovery value can reach more than 90%, the performance of restraining water dispersion and cuttings expansion is good, the heat roll recovery rate can reach more than 85%, and the SSSI value shows that its settlement stability performance is good;Its plugging performance is good under high temperature and high pressure. It laid the foundation for the next step to promote the field application of the drilling fluid system.展开更多
基金support by the financial support of the National Nature Science Foundation of China(No.52274001,No.52074018)China Petrochemical Corporation(No.p21069)The financial support of Fundamental Research Funds for the Central Universities(buctrc202017)。
文摘The study considers gas compression properties,gas slippage,back pressure(BP),phase transition(PT),well depth,and differences in gas-liquid physical properties.A new temperature model for multiphase flow is proposed by considering phase transition in the drilling process.The mathematical model of multiphase flow is solved using the finite difference method with annulus mesh division for grid nodes,and a module for multiphase flow calculation and analysis is developed.Numerical results indicate that the temperature varies along the annulus with the variation of gas influx at the bottom of the well.During the process of controlled pressure drilling,as gas slips along the annulus to the wellhead,its volume continuously expands,leading to an increase in the gas content within the annulus,and consequently,an increase in the pressure drop caused by gas slippage.The temperature increases with the increase in BP and decreases in gas influx rate and wellbore diameter.During gas influx,the thermal conductivity coefficient for the gas-drilling mud two phases is significantly weakened,resulting in a considerable change in temperature along the annulus.In the context of MPD,the method of slightly changing the temperature along the annulus by controlling the back pressure is feasible.
基金The work is supported by the Integration and Testing of Safe and Fast Drilling and Completion Technologies for Complex Ultra-Deep Wells(2020F-46)Major Technology Field Test of Joint-Stock Company(Drilling and Production Engineering).Xuyang received the grant.
文摘Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydration.An infrared spectral method and a thermogravimetric technique were used to characterize the chemical composition of the HLMP and evaluate its heat stability.Experiments were conducted to measure the linear swelling,rolling recovery rate,and bentonite inhibition rate and evaluate accordingly the inhibition performance of the HLMP.Moreover,the HLMP was characterized through measurements of the zeta potential,particle size distribution,contact angles,and interlayer space testing.As confirmed by the results,the HLMP could successfully be synthesized with a favorable heat stability.Furthermore,favorable results were found for the inhibitory processes of the HLMP on swelling and dispersed hydration during mud shale hydration.The positively charged HLMP could be electrically neutralized with clay particles,thereby inhibiting diffusion in the double electron clay layers.The hydrophobic group in the HLMP molecular structure resulted in the formation of a hydrophobic membrane on the rock surface,enhancing the hydrophobicity of the rock.In addition,the small molecules of the HLMP could plug the spaces between the layers of bentonite crystals,thereby reducing the entry of water molecules and inhibiting shale hydration.
基金supports from the National Key Research and Development Program of China(2022YFB3207502).
文摘High-temperature thin-film thermocouples(TFTCs)have attracted significant attention in the aerospace and steel metallurgy industry.However,previous studies on TFTCs have primarily focused on the two-dimensional planar-type,whose thermal sensitive area has to be perpendicular to the test environment,and therefore affects the thermal fluids pattern or loses accuracy.In order to address this problem,recent studies have developed three-dimensional probe-type TFTCs,which can be set parallel to the test environment.Nevertheless,the probe-type TFTCs are limited by their measurement threshold and poor stability at high temperatures.To address these issues,in this study,we propose a novel probe-type TFTC with a sandwich structure.The sensitive layer is compounded with indium oxide doped zinc oxide and fabricated using screen-printing technology.With the protection of sandwich structure on electrode film,the sensor demonstrates robust high-temperature stability,enabling continuous working at 1200℃ above 5 h with a low drift rate of 2.3℃·h^(−1).This sensor exhibits a high repeatability of 99.3% when measuring a wide range of temperatures,which is beyond the most existing probe-type TFTCs reported in the literature.With its excellent high-temperature performance,this temperature sensor holds immense potentials for enhancing equipment safety in the aerospace engineering and ensuring product quality in the steel metallurgy industry.
基金Supported by the Projects of National Natural Science Foundation of China(52288101,52174014,52374023)。
文摘The research progress of deep and ultra-deep drilling fluid technology systematically reviewed,the key problems existing are analyzed,and the future development direction is proposed.In view of the high temperature,high pressure and high stress,fracture development,wellbore instability,drilling fluid lost circulation and other problems faced in the process of deep and ultra-deep complex oil and gas drilling,scholars have developed deep and ultra-deep high-temperature and high-salt resistant water-based drilling fluid technology,high-temperature resistant oil-based/synthetic drilling fluid technology,drilling fluid technology for reservoir protection and drilling fluid lost circulation control technology.However,there are still some key problems such as insufficient resistance to high temperature,high pressure and high stress,wellbore instability and serious lost circulation.Therefore,the development direction of deep and ultra-deep drilling fluid technology in the future is proposed:(1)The technology of high-temperature and high-salt resistant water-based drilling fluid should focus on improving high temperature stability,improving rheological properties,strengthening filtration control and improving compatibility with formation.(2)The technology of oil-based/synthetic drilling fluid resistant to high temperature should further study in the aspects of easily degradable environmental protection additives with low toxicity such as high temperature stabilizer,rheological regulator and related supporting technologies.(3)The drilling fluid technology for reservoir protection should be devoted to the development of new high-performance additives and materials,and further improve the real-time monitoring technology by introducing advanced sensor networks and artificial intelligence algorithms.(4)The lost circulation control of drilling fluid should pay more attention to the integration and application of intelligent technology,the research and application of high-performance plugging materials,the exploration of diversified plugging techniques and methods,and the improvement of environmental protection and production safety awareness.
基金funded by the Key Program of National Natural Science Foundation of China (Grant No.51734010)the Startup Fund of Changzhou University Science Research (Grant No.ZMF22020060).
文摘Multi-gradient drilling is a new offshore drilling method.The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore pressure.In this study,a new heat transfer model is proposed by which the variable mass flow is properly taken into account.Using this model,the effects of the main factors influencing the wellbore temperature are analyzed.The results indicate that at the position where the separation injection device is installed,the temperature increase of the fluid in the drill pipe is mitigated due to the inflow/outflow of hollow spheres,and the temperature drop of the fluid in the annulus also decreases.In addition,a lower separation efficiency of the device,a shallower installation depth and a smaller circulating displacement tend to increase the temperature near the bottom of the annulus,thereby helping to reduce the hydrate generation area and playing a positive role in the prevention and control of hydrates in deepwater drilling.
基金Supported by Foundation for High-level Talents in Higher Education of Guangdong,China (Grant No.501111018)Panyu District Science and Technology Program of China (Grant No.2009-Z-53-1)
文摘Many researches on drilling force and temperature have been done with the aim to reduce the labour intensiveness of surgery, avoid unnecessary damage and improve drilling quality. However, there has not been a systematic study of mid- and high-speed drilling under dry and physiological conditions（injection of saline）. Furthermore, there is no consensus on optimal drilling parameters. To study these parameters under dry and physiological drilling conditions, pig humerus bones are drilled with medical twist drills operated using a wide range of drilling speeds and feed rates. Drilling force and temperature are measured using a YDZ-II01W dynamometer and a NEC TVS-500EX thermal infrared imager, respectively, to evaluate internal bone damage. To evaluate drilling quality, bone debris and hole morphology are observed by SEM（scanning electron microscopy）. Changes in drilling force and temperature give similar results during drilling such that the value of each parameter peaks just before the drill penetrates through the osteon of the compact bone into the trabeculae of the spongy bone. Drilling temperatures under physiological conditions are much lower than those observed under dry conditions, while a larger drilling force occurs under physiological conditions than dry conditions. Drilling speed and feed rate have a significant influence on drilling force, temperature, bone debris and hole morphology. The investigation of the effect of drilling force and temperature on internal bone damage reveals that a drilling speed of 4500 r/min and a feed rate of 50 mm/min are recommended for bone drilling under physiological conditions. Drilling quality peaks under these optimal parameter conditions. This paper proposes the optimal drilling parameters under mid- and high-speed surgical drilling, considering internal bone damage and drilling quality, which can be looked as a reference for surgeons performing orthopedic operations.
文摘To maintain tight control over rheological properties of high-density water-based drilling fluids, it is essential to understand the factors influencing the theology of water-based drilling fluids. This paper examines temperature effects on the rheological properties of two types of high-density water-based drilling fluids （fresh water-based and brine-based） under high temperature and high pressure （HTHP） with a Fann 50SL rheometer. On the basis of the water-based drilling fluid systems formulated in laboratory, this paper mainly describes the influences of different types and concentration of clay, the content of a colloid stabilizer named GHJ-1 and fluid density on the rheological parameters such as viscosity and shear stress. In addition, the effects of aging temperature and aging time of the drilling fluid on these parameters were also examined. Clay content and proportions for different densities of brine-based fluids were recommended to effectively regulate the rheological properties. Four theological models, the Bingham, power law, Casson and H-B models, were employed to fit the rheological parameters. It turns out that the H-B model was the best one to describe the rheological properties of the high-density drilling fluid under HTHP conditions and power law model produced the worst fit. In addition, a new mathematical model that describes the apparent viscosity as a function of temperature and pressure was established and has been applied on site.
基金Project(50574061) supported by the National Natural Science Foundation of ChinaProject(IRT0411) supported by the Changjiang Scholars and Innovative Research Team,Ministry of Education
文摘The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental results show that the apparent viscosity,plastic viscosity and yield point decrease with the increase of temperature,and increase with the increase of pressure.The effect of pressure on the apparent viscosity,plastic viscosity and yield point is considerable at ambient temperature.However,this effect gradually reduces with the increase of temperature.The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells.On the basis of numerous experiments,the model for predict the apparent viscosity,plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis.It is confirmed that the calculated data are in good agreement with the measured data,and the correlation coefficients are more than 0.98.The model is convenient for use and suitable for the application in drilling operations.
文摘Temperature curves reflect geothermal gradients and local temperature anomalies, thus providing a new understanding of the underground reservoir conditions. When encountering caverns or fractures and fissures during drilling, lost circulation may occur and result in a change to the original formation temperature field, and in severe cases, even the conventional open hole well logging data cannot be obtained. This paper uses finite element analysis software COMSOL to establish a heat transfer model for the wellbore/reservoir formation system during drilling and shut-in in the presence of lost circulation, and a case study is made in a carbonate reservoir in the Tahe oilfield. On the basis of the above, we analyze the temperature distribution in the leakage zone, and the studies have shown that the leakage and petrophysical properties have an impact on the temperature of the wellbore and formation, hence we can estimate the reservoir permeability using the temperature data. In addition, the determination of the temperature recovery time after some drilling fluids have leaked into the formation will help in recognizing the subsurface temperature field of the carbonate formation correctly, thus enhancing production logging interpretation accuracy and improving the understanding of later measurements.
基金Projects(51475073,51605076,51875079) supported by the National Natural Science Foundation of ChinaProject(2017YFB1301701) supported by the National Key Research and Development Program of China
文摘The phenomenon of heat accumulation and transportation in the composite materials is a very typical and critical issue during drilling process.In this study,a three-dimensional temperature field prediction model is proposed using finite difference method,based on the partly homogenization hypothesis of material,to predict temperature field in the process of drilling unidirectional carbon fiber/epoxy(C/E)composites.According to the drilling feed motion,drilling process is divided into four stages to study the temperature distributing characteristics.The results show that the temperature distribution predicted by numerical study has a good agreement with the experimental results.The temperature increases with increasing the drilling depth,and the burn phenomena is observed due to the heat accumulation,especially at the drill exit.Due to the fiber orientation,an elliptical shape of the temperature field along the direction is found for both numerical and experimental studies of C/E composites drilling process.
基金financially supported by the Natural Science Foundation of China(Grants 51904328)the Natural Science Foundation of China(Grants U1762212)Fundamental Research Funds for the Central Universities(Grants 27R1702031A)
文摘Drilling fluids face failure during drilling deep reservoir with high temperature and high salt.The experimental results show that high temperature and salinity reduce the negative charge on the surface of bentonite in the drilling fluid and cause the coalescence of bentonite particles.As a result,the particles coalesce,the grid structure is destroyed,and the rheological properties,rock-carrying capacity and filtration properties are lost.To resolve the foregoing,in this study,0.05-wt%carbon nanotubes are introduced into a 4%bentonite drilling fluid under conditions where the temperature and concentration of added Na Cl reach 180°C and 10 wt%,respectively.The carbon nanotubes adsorb on the bentonite surface and increase the space among bentonite particles.The steric hindrance prevents the coalescence of bentonite in high temperature and high salt environment.Thus bentonite maintains the small size distribution of bentonite and supports the bentonite grid structure in the drilling fluid.As a result,the rock-carrying capacity of the drilling fluid increases by 85.1%.Moreover,the mud cake formed by the accumulation of small-sized bentonite particles is dense;consequently,the filtration of bentonite drilling fluid reduced by 30.2%.
基金the financial support from the National Science and Technology Key Projects(2008ZX05056-002-03-04 and 2008ZX05030-005-07-03)
文摘With the rapid development of deepwater drilling operations,more and more complex technical challenges have to be faced due to the rigorous conditions encountered.One of these challenges is that the drilling fluid used must had good rheological properties at low temperatures and high ability to inhibit hydrate formation.Synthetic drilling fluid has been widely applied to deepwater drilling operations due to its high penetration rate,excellent rheological properties,good ability to prevent hydrate formation,and high biodegradability.A synthetic drilling fluid formulation was developed in our laboratory.The rheological properties of this drilling fluid at low temperatures （0-20 °C） were tested with a 6-speed viscometer and its ability to inhibit hydrate formation was evaluated at 20 MPa CH 4 gas and 0 °C by differential scanning calorimetry （DSC）.Several factors influencing the low temperature rheological properties of this synthetic drilling fluid were studied in this paper.These included the viscosity of the base fluid,the amount of CEMU and organic clay,and the water volume fraction.
基金Natural and Science Foundation of China(Grant No.52205455)Fujian Provincial Natural and Science Foundation(Grant No.2021J01560)Fujian Provincial Education and Scientific Research Foundation for Young Teachers(Grant No.JAT190006).
文摘Drilling is regarded as the most complex manufacturing process compared with other conventional machining processes.During the drilling process,most of the energy consumed in metal cutting is converted to heat and increases temperature considerably.The resulting thermal phenomena are important since they influence the mode of deformation,the final metallurgical state of the machined surface,and the rate of tool wear.Hence,understanding the temperature characteristics in the drilling process is crucial for enhancing the drill performance and process efficiency.Extensive efforts have been conducted to measure and control the drilling tool temperature successively.However,very few studies have been conducted from a comprehensive perspective to review all the efforts.To address this gap in the literature,a rigorous review concerning the state-of-the-art results and advances in drilling tool temperature is presented in this paper by referring to the wide comparisons among literature analyses.The multiple aspects of drilling tool temperature are precisely detailed and discussed in terms of theoretical analysis and thermal modeling,methods for temperature measuring,the effect of cutting parameters,tool geometries and hole-making methods on temperature and temperature controlling by different cooling methods.In conclusion,several possible future research directions are discussed to offer potential insights for the drilling community and future researchers.
基金Supported by the "863" Program(2003AA131100-02-06)the National Natural Science Foundation of China(50274061)
文摘The working conditions of the MK-3 type full hydraulic tunnel drilling machine during the course of drilling were analyzed. Based on the energy balance governing equations for the drill rod, the temperature field of drill rod at the normal and non-normal working conditions was numerically obtained. The numerical results show that the maximum temperature at the head of drill rod under the normal working circumstance is insufficient to ignite the gas. But under the non-normal working condition, the local high temperature can ignite the gas easily and cause the fire. In order to prevent the gas fire, the occurrence of the non-normal operating condition must be prevented as far as possible during the drilling.
文摘Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle（B4C） reinforced metal matrix composites（MMCs） with different drills. The effect of particle content, cutting speed, feed rate and tool material on the maximum drilling temperature was investigated. The drilling parameters were optimized based on multiple performance characteristics in terms of the maximum cutting temperature and tool wear. According to the results, the most influential control factors on the cutting temperatures are found to be particle fraction, feed rate and interaction between the cutting speed and particle content, respectively. The influences of the cutting speed and drill material on the drilling temperature are found to be relatively lower for the used range of parameters. Minimum cutting temperatures are obtained with lower particle fraction and cutting speed, with relatively higher feed rates and carbide tools. The results reveal that optimal combination of the drilling parameters can be used to obtain both minimum cutting temperature and tool wear.
基金funded by the National Basic Research Program of China (No. 2015CB251201)the NSFC-Shandong Joint Fund for Marine Science Research Centers (No. U1606401)+3 种基金the Scientific and Technological Innovation Project financially supported by Qingdao National Laboratory for Marine Science and Technology (No. 2016ASKJ13)the Major National Science and Technology Programs (No. 016ZX05024-001-002)the Natural Science Foundation of Hainan (No. ZDYF2016215)Key Science and Technology Foundation of Sanya (Nos. 2017PT13, 2017PT2014)
文摘Decreasing the risks and geohazards associated with drilling engineering in high-temperature high-pressure(HTHP) geologic settings begins with the implementation of pre-drilling prediction techniques(PPTs). To improve the accuracy of geopressure prediction in HTHP hydrocarbon reservoirs offshore Hainan Island, we made a comprehensive summary of current PPTs to identify existing problems and challenges by analyzing the global distribution of HTHP hydrocarbon reservoirs, the research status of PPTs, and the geologic setting and its HTHP formation mechanism. Our research results indicate that the HTHP formation mechanism in the study area is caused by multiple factors, including rapid loading, diapir intrusions, hydrocarbon generation, and the thermal expansion of pore fluids. Due to this multi-factor interaction, a cloud of HTHP hydrocarbon reservoirs has developed in the Ying-Qiong Basin, but only traditional PPTs have been implemented, based on the assumption of conditions that do not conform to the actual geologic environment, e.g., Bellotti's law and Eaton's law. In this paper, we focus on these issues, identify some challenges and solutions, and call for further PPT research to address the drawbacks of previous works and meet the challenges associated with the deepwater technology gap. In this way, we hope to contribute to the improved accuracy of geopressure prediction prior to drilling and provide support for future HTHP drilling offshore Hainan Island.
文摘The Qaidam Basin in the NE Tibetan Plateau has contributed the largest amount of potash in China.However,how the potash was formed has long been a subject of debate.Here we carried out a deep drilling
文摘The wellbore temperature has an important effect on design and drilling of deep well.<b> </b>Based on energy conservation equations and actual drilling data of one deep well, the wellbore temperature distribution was simulated and the influence of different parameters on the wellbore temperature was revealed <span>using the software of Hydraulics Analysis System. The results show that,</span> while drilling, the mud temperature in wellbore gradually decreases from the formation temperature to the stable temperature, and it is higher than the mud <span>inlet temperature on ground, the annular temperature is higher than the </span>temperature in drill string, and the bottom hole temperature is higher than the ground temperature. The effect of geothermal gradient on wellbore temperature is great, while the mud density is negligible. The bottom hole temperature increases with the increase of mud inlet temperature, geothermal gradient, mud thermal conductivity and decrease of mud flow rate, mud specific heat and mud density.
文摘Combined with the current research status in this area at home and abroad, with the improvement of salt and high temperature resistance as the research goal, the laboratory research of salt and high temperature resistant drilling fluid system has been carried out, and lubricants, inhibitors and stabilizers have been optimized. The final drilling fluid formula is: water + 3% sepiolite + 0.3% Na<sub>2</sub>CO<sub>3</sub> + 3% RH-225 + 3% KCOOH + 3% G-SPH + 3% CQA-10 + 1.5% ZX-1 + Xinjiang barite, density 2.2 g/cm<sup>3</sup>, using hot-rolling furnace, environmental scanning electron microscope, high temperature and high pressure plugging instrument and Zeiss microscopes and other instruments use core immersion experiments, permeability recovery value experiments, and static stratification index methods to perform temperature resistance, reservoir protection, plugging performance, and static settlement stability performance of the configured drilling fluid., Inhibition performance, biological toxicity, salt resistance, anti-pollution performance have been tested, and it is concluded that the temperature resistance is good under the condition of 210°C, and the salt resistance can meet the requirements of 20% NaCl + 0.5% CaCl<sub>2</sub> concentration. It has a good reservoir protection effect, the permeability recovery value can reach more than 90%, the performance of restraining water dispersion and cuttings expansion is good, the heat roll recovery rate can reach more than 85%, and the SSSI value shows that its settlement stability performance is good;Its plugging performance is good under high temperature and high pressure. It laid the foundation for the next step to promote the field application of the drilling fluid system.
