Recycling gas drilling is a new drilling technology. This paper can be divided into three parts, with the purpose of introducing and analyzing the characteristics of this new technology. First, the major equipment cha...Recycling gas drilling is a new drilling technology. This paper can be divided into three parts, with the purpose of introducing and analyzing the characteristics of this new technology. First, the major equipment characteristic of this technology was introduced. Secondly, compared with conventional gas drilling, Angel＇s model was used to analyze the wellbore flow characteristics. Due to the closed loop and the effect of back pressure caused by the equipment, the gas flow rate decreases dramatically during drilling. Apart from this, it is also found that the kinetic energy at the casing shoe is always smaller than that at the top of the collar. The proposing of the drilling limit concept points out the basic difference between the two gas drilling technologies. Lastly, according to the results of the theoretical analysis, gas supplement operations for the wellbore must be conducted. Thus, two gas supplement schemes are presented in this paper, to provide some guidance for field operations.展开更多
The directional and cluster drilling technology developed very fast in 1980s.4317 directional wells were completed by CNPC during the period of the"Seventh Five-Year Plan”which was 4.65 times.that of the"Si...The directional and cluster drilling technology developed very fast in 1980s.4317 directional wells were completed by CNPC during the period of the"Seventh Five-Year Plan”which was 4.65 times.that of the"Sixth Five-Year Plan".The CNPC completed 1759 directional wells in 1991 and 1900 direetional wells in 1992.which was 20%of the total wells completed in the same years.展开更多
Ultra-deep formations in China contain rich hydrocarbon resources.In recent years,the number of ultradeep wells has been continuously increasing.However,efforts to facilitate tlte drilling and exploration of these ult...Ultra-deep formations in China contain rich hydrocarbon resources.In recent years,the number of ultradeep wells has been continuously increasing.However,efforts to facilitate tlte drilling and exploration of these ultra-deep reservoirs are facing many challenges,such as complicated formation pressures,complicated formation lithologic features,complicated formation fluids,difficulties in the accurate calculation of formation parameters,difficulties in borehole structure design optimization,instabilities in the performances of drilling fluid and key cementing materials/systems,high temperature-resistance and pressure-resistance requirements for downhole tools and instruments,complicated engineering problems,and slow drilling speeds.Under such circumstances,it is very difficult to ensure the performance of such drilling operations.In order to address these challenges,SINOPEC has developed relevant drilling technologies for ultra-deep wells in complicated geological conditions through intensive research on accurate descriptions of complex geologic characteristics,borehole structure design optimization,fast drilling techniques for deep and hard formations,temperature-resistant highdensity drilling fluid,anti-channeling cementing in high-pressure gas wells,borehole trajectory control in ultra-deep horizontal wells and other key technologies.These technologies can provide sound engineering and technical support for tlte exploration and development of hydrocarbon resources in ultra-deep formations in China.展开更多
By benchmarking with the iteration of drilling technology,fracturing technology and well placement mode for shale oil and gas development in the United States and considering the geological characteristics and develop...By benchmarking with the iteration of drilling technology,fracturing technology and well placement mode for shale oil and gas development in the United States and considering the geological characteristics and development difficulties of shale oil in the Jiyang continental rift lake basin,East China,the development technology system suitable for the geological characteristics of shale oil in continental rift lake basins has been primarily formed through innovation and iteration of the development,drilling and fracturing technologies.The technology system supports the rapid growth of shale oil production and reduces the development investment cost.By comparing it with the shale oil development technology in the United States,the prospect of the shale oil development technology iteration in continental rift lake basins is proposed.It is suggested to continuously strengthen the overall three-dimensional development,improve the precision level of engineering technology,upgrade the engineering technical indicator system,accelerate the intelligent optimization of engineering equipment,explore the application of complex structure wells,form a whole-process integrated quality management system from design to implementation,and constantly innovate the concept and technology of shale oil development,so as to promote the realization of extensive,beneficial and high-quality development of shale oil in continental rift lake basins.展开更多
A procedure to recognize individual discontinuities in rock mass from measurement while drilling(MWD)technology is developed,using the binary pattern of structural rock characteristics obtained from in-hole images for...A procedure to recognize individual discontinuities in rock mass from measurement while drilling(MWD)technology is developed,using the binary pattern of structural rock characteristics obtained from in-hole images for calibration.Data from two underground operations with different drilling technology and different rock mass characteristics are considered,which generalizes the application of the methodology to different sites and ensures the full operational integration of MWD data analysis.Two approaches are followed for site-specific structural model building:a discontinuity index(DI)built from variations in MWD parameters,and a machine learning(ML)classifier as function of the drilling parameters and their variability.The prediction ability of the models is quantitatively assessed as the rate of recognition of discontinuities observed in borehole logs.Differences between the parameters involved in the models for each site,and differences in their weights,highlight the site-dependence of the resulting models.The ML approach offers better performance than the classical DI,with recognition rates in the range 89%to 96%.However,the simpler DI still yields fairly accurate results,with recognition rates 70%to 90%.These results validate the adaptive MWD-based methodology as an engineering solution to predict rock structural condition in underground mining operations.展开更多
The general layout of 6th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process f...The general layout of 6th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process flow that is aimed at improving efficiency, while giving attention to stability and safety at the same time. The paper describes the process flow of dual drilling centers and a hierarchical division of rigs based on the different modes of transportation of various drilling support systems. The general layout-centripetal overall arrangement spatially was determined based on drilling efficiency. We derived our modules according to drilling functionality; the modules became our basic layout units. We applied different layout algorithm to mark out the upper and lower decks. That is, the upper deck was designed based on the lowest transportation cost while the lower deck＇s calculations were based on the best-fit scope. Storage configurations in columns and pontoons were also considered for the layout design. Finally the center of gravity was taken into consideration and the general layout was adjusted accordingly, to result in an optimal center of gravity. The methodology of the general layout can provide a reference for implementation of domestic designs of semi-submersible rigs.展开更多
The presence of seam gas in the form of methane or carbon dioxide presents a hazard to underground coal mining operations.In-seam drilling has been undertaken for the past three decades for gas drainage to reduce the ...The presence of seam gas in the form of methane or carbon dioxide presents a hazard to underground coal mining operations.In-seam drilling has been undertaken for the past three decades for gas drainage to reduce the risk of gas outburst and lower the concentrations of seam gas in the underground ventilation.The drilling practices have reflected the standards of the times and have evolved with the development of technology and equipment and the needs to provide a safe mining environment underground.Early practice was to adapt equipment from other felds,with rotary drilling being the only form of drilling available.This form of drainage allowed various levels of gas drainage coverage but with changing emphasis,research and development within the coal industry has created specifc equipment,technology and practices to accurately place in-seam boreholes to provide effcient and effective gas drainage.Research into gas content determination established a standard for the process and safe levels for mining operations to continue.Surveying technology improved from the wire-line,single-shot Eastman survey instruments which was time-dependent on borehole depth to electronic instruments located in the drill string which transmitted accurate survey data to the drilling crew without time delays.This allowed improved directional control and increased drilling rates.Directional drilling technology has now been established as the industry standard to provide effective gas drainage drilling.Exploration was identifed as an additional beneft with directional drilling as it has the ability to provide exploration data from long boreholes.The ability of the technology to provide safe and reliable means to investigate the need for inrush protection and water drainage ahead of mining has been established.Directional drilling technology has now been introduced to the Chinese coal industry for gas drainage through a practice of auditing,design,supply,training and ongoing support.Experienced drilling crews can offer site specifc gas drainage drilling services utilising the latest equipment and technology.展开更多
The present study aims at investigating the effect of temperature variation due to heat transfer between the formation and drilling fluids considering influx from the reservoir in the underbalanced drilling condition....The present study aims at investigating the effect of temperature variation due to heat transfer between the formation and drilling fluids considering influx from the reservoir in the underbalanced drilling condition. Gas-liquid-solid three-phase flow model considering transient thermal interaction with the formation was applied to simulate wellbore fluid to calculate the wellbore temperature and pressure and analyze the influence of different parameters on fluid pressure and temperature distribution in annulus. The results show that the non-isothermal three-phase flow model with thermal consideration gives more accurate prediction of bottom-hole pressure(BHP) compared to other models considering geothermal temperature. Viscous dissipation, the heat produced by friction between the rotating drilling-string and well wall and drill bit drilling, and influx of oil and gas from reservoir have significant impact on the distribution of fluid temperature in the wellbore, which in turn affects the BHP. Bottom-hole fluid temperature decreases with increasing liquid flow rate, circulation time, and specific heat of liquid and gas but it increases with increasing in gas flow rate. It was found that BHP is strongly depended on the gas and liquid flow rates but it has weak dependence on the circulation time and specific heat of liquid and gas. BHP increase with increasing liquid flow rate and decreases with increasing gas flow rate.展开更多
In the recent years,CNPC has examined and approved more than 600 items of gadgets for extensive application.The approved projects inc-lude both single item of advanced and applicable technology and a number of items o...In the recent years,CNPC has examined and approved more than 600 items of gadgets for extensive application.The approved projects inc-lude both single item of advanced and applicable technology and a number of items of supporting technology which are broght together in one area to solve the regional problems and boost the production capacity.As the economic reform is making progress,,theI mandatory planned system will be gradually replaced by the new guiding planned managerial system.展开更多
基金financial support from the National Natural Science Foundation of China (50974021)Major Project of Chinese National Programs for Fundamental Research and Development (973 Program:2010CB226704)
文摘Recycling gas drilling is a new drilling technology. This paper can be divided into three parts, with the purpose of introducing and analyzing the characteristics of this new technology. First, the major equipment characteristic of this technology was introduced. Secondly, compared with conventional gas drilling, Angel＇s model was used to analyze the wellbore flow characteristics. Due to the closed loop and the effect of back pressure caused by the equipment, the gas flow rate decreases dramatically during drilling. Apart from this, it is also found that the kinetic energy at the casing shoe is always smaller than that at the top of the collar. The proposing of the drilling limit concept points out the basic difference between the two gas drilling technologies. Lastly, according to the results of the theoretical analysis, gas supplement operations for the wellbore must be conducted. Thus, two gas supplement schemes are presented in this paper, to provide some guidance for field operations.
文摘The directional and cluster drilling technology developed very fast in 1980s.4317 directional wells were completed by CNPC during the period of the"Seventh Five-Year Plan”which was 4.65 times.that of the"Sixth Five-Year Plan".The CNPC completed 1759 directional wells in 1991 and 1900 direetional wells in 1992.which was 20%of the total wells completed in the same years.
基金Key National Science and Technology Development Project for the"Twelfth Five-year Plan"-"Development of large-scale oil/gas fields and coalbed methane(CBM)",Subtopic 6:"Key technology for boreholes of oil/gas producers in marine carbonate rocks"(No.:2011ZX05005-006)
文摘Ultra-deep formations in China contain rich hydrocarbon resources.In recent years,the number of ultradeep wells has been continuously increasing.However,efforts to facilitate tlte drilling and exploration of these ultra-deep reservoirs are facing many challenges,such as complicated formation pressures,complicated formation lithologic features,complicated formation fluids,difficulties in the accurate calculation of formation parameters,difficulties in borehole structure design optimization,instabilities in the performances of drilling fluid and key cementing materials/systems,high temperature-resistance and pressure-resistance requirements for downhole tools and instruments,complicated engineering problems,and slow drilling speeds.Under such circumstances,it is very difficult to ensure the performance of such drilling operations.In order to address these challenges,SINOPEC has developed relevant drilling technologies for ultra-deep wells in complicated geological conditions through intensive research on accurate descriptions of complex geologic characteristics,borehole structure design optimization,fast drilling techniques for deep and hard formations,temperature-resistant highdensity drilling fluid,anti-channeling cementing in high-pressure gas wells,borehole trajectory control in ultra-deep horizontal wells and other key technologies.These technologies can provide sound engineering and technical support for tlte exploration and development of hydrocarbon resources in ultra-deep formations in China.
基金Supported by the Strategic Research and Technical Consultation Project of Sinopec Science and Technology CommissionSinopec Major Science and Technology Project(P22037)。
文摘By benchmarking with the iteration of drilling technology,fracturing technology and well placement mode for shale oil and gas development in the United States and considering the geological characteristics and development difficulties of shale oil in the Jiyang continental rift lake basin,East China,the development technology system suitable for the geological characteristics of shale oil in continental rift lake basins has been primarily formed through innovation and iteration of the development,drilling and fracturing technologies.The technology system supports the rapid growth of shale oil production and reduces the development investment cost.By comparing it with the shale oil development technology in the United States,the prospect of the shale oil development technology iteration in continental rift lake basins is proposed.It is suggested to continuously strengthen the overall three-dimensional development,improve the precision level of engineering technology,upgrade the engineering technical indicator system,accelerate the intelligent optimization of engineering equipment,explore the application of complex structure wells,form a whole-process integrated quality management system from design to implementation,and constantly innovate the concept and technology of shale oil development,so as to promote the realization of extensive,beneficial and high-quality development of shale oil in continental rift lake basins.
基金conducted under the illu MINEation project, funded by the European Union’s Horizon 2020 research and innovation program under grant agreement (No. 869379)supported by the China Scholarship Council (No. 202006370006)
文摘A procedure to recognize individual discontinuities in rock mass from measurement while drilling(MWD)technology is developed,using the binary pattern of structural rock characteristics obtained from in-hole images for calibration.Data from two underground operations with different drilling technology and different rock mass characteristics are considered,which generalizes the application of the methodology to different sites and ensures the full operational integration of MWD data analysis.Two approaches are followed for site-specific structural model building:a discontinuity index(DI)built from variations in MWD parameters,and a machine learning(ML)classifier as function of the drilling parameters and their variability.The prediction ability of the models is quantitatively assessed as the rate of recognition of discontinuities observed in borehole logs.Differences between the parameters involved in the models for each site,and differences in their weights,highlight the site-dependence of the resulting models.The ML approach offers better performance than the classical DI,with recognition rates in the range 89%to 96%.However,the simpler DI still yields fairly accurate results,with recognition rates 70%to 90%.These results validate the adaptive MWD-based methodology as an engineering solution to predict rock structural condition in underground mining operations.
基金Supported by the National High Technology Research and Development Program of China (863 Program) under Grant No.2006AA09A104
文摘The general layout of 6th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process flow that is aimed at improving efficiency, while giving attention to stability and safety at the same time. The paper describes the process flow of dual drilling centers and a hierarchical division of rigs based on the different modes of transportation of various drilling support systems. The general layout-centripetal overall arrangement spatially was determined based on drilling efficiency. We derived our modules according to drilling functionality; the modules became our basic layout units. We applied different layout algorithm to mark out the upper and lower decks. That is, the upper deck was designed based on the lowest transportation cost while the lower deck＇s calculations were based on the best-fit scope. Storage configurations in columns and pontoons were also considered for the layout design. Finally the center of gravity was taken into consideration and the general layout was adjusted accordingly, to result in an optimal center of gravity. The methodology of the general layout can provide a reference for implementation of domestic designs of semi-submersible rigs.
文摘The presence of seam gas in the form of methane or carbon dioxide presents a hazard to underground coal mining operations.In-seam drilling has been undertaken for the past three decades for gas drainage to reduce the risk of gas outburst and lower the concentrations of seam gas in the underground ventilation.The drilling practices have reflected the standards of the times and have evolved with the development of technology and equipment and the needs to provide a safe mining environment underground.Early practice was to adapt equipment from other felds,with rotary drilling being the only form of drilling available.This form of drainage allowed various levels of gas drainage coverage but with changing emphasis,research and development within the coal industry has created specifc equipment,technology and practices to accurately place in-seam boreholes to provide effcient and effective gas drainage.Research into gas content determination established a standard for the process and safe levels for mining operations to continue.Surveying technology improved from the wire-line,single-shot Eastman survey instruments which was time-dependent on borehole depth to electronic instruments located in the drill string which transmitted accurate survey data to the drilling crew without time delays.This allowed improved directional control and increased drilling rates.Directional drilling technology has now been established as the industry standard to provide effective gas drainage drilling.Exploration was identifed as an additional beneft with directional drilling as it has the ability to provide exploration data from long boreholes.The ability of the technology to provide safe and reliable means to investigate the need for inrush protection and water drainage ahead of mining has been established.Directional drilling technology has now been introduced to the Chinese coal industry for gas drainage through a practice of auditing,design,supply,training and ongoing support.Experienced drilling crews can offer site specifc gas drainage drilling services utilising the latest equipment and technology.
文摘The present study aims at investigating the effect of temperature variation due to heat transfer between the formation and drilling fluids considering influx from the reservoir in the underbalanced drilling condition. Gas-liquid-solid three-phase flow model considering transient thermal interaction with the formation was applied to simulate wellbore fluid to calculate the wellbore temperature and pressure and analyze the influence of different parameters on fluid pressure and temperature distribution in annulus. The results show that the non-isothermal three-phase flow model with thermal consideration gives more accurate prediction of bottom-hole pressure(BHP) compared to other models considering geothermal temperature. Viscous dissipation, the heat produced by friction between the rotating drilling-string and well wall and drill bit drilling, and influx of oil and gas from reservoir have significant impact on the distribution of fluid temperature in the wellbore, which in turn affects the BHP. Bottom-hole fluid temperature decreases with increasing liquid flow rate, circulation time, and specific heat of liquid and gas but it increases with increasing in gas flow rate. It was found that BHP is strongly depended on the gas and liquid flow rates but it has weak dependence on the circulation time and specific heat of liquid and gas. BHP increase with increasing liquid flow rate and decreases with increasing gas flow rate.
文摘In the recent years,CNPC has examined and approved more than 600 items of gadgets for extensive application.The approved projects inc-lude both single item of advanced and applicable technology and a number of items of supporting technology which are broght together in one area to solve the regional problems and boost the production capacity.As the economic reform is making progress,,theI mandatory planned system will be gradually replaced by the new guiding planned managerial system.
