Gas flexible pipes are critical multi-layered equipment for offshore oil and gas development.Under high pressure conditions,small molecular components of natural gas dissolve into the polymer inner liner of the flexib...Gas flexible pipes are critical multi-layered equipment for offshore oil and gas development.Under high pressure conditions,small molecular components of natural gas dissolve into the polymer inner liner of the flexible pipes and further diffuse into the annular space,incurring annular pressure build-up and/or production of acidic environment,which poses serious challenges to the structure and integrity of the flexible pipes.Gas permeation in pipes is a complex phenomenon governed by various factors such as internal pressure and temperature,annular structure,external temperature.In a long-distance gas flexible pipe,moreover,gas permeation exhibits non-uniform features,and the gas permeated into the annular space flows along the metal gap.To assess the complex gas transport behavior in long-distance gas flexible pipes,a mathematical model is established in this paper considering the multiphase flow phenomena inside the flexible pipes,the diffusion of gas in the inner liner,and the gas seepage in the annular space under varying permeable properties of the annulus.In addition,the effect of a variable temperature is accounted.A numerical calculation method is accordingly constructed to solve the coupling mathematical equations.The annular permeability was shown to significantly influence the distribution of annular pressure.As permeability increases,the annular pressure tends to become more uniform,and the annular pressure at the wellhead rises more rapidly.After annular pressure relief followed by shut-in,the pressure increase follows a convex function.By simulating the pressure recovery pattern after pressure relief and comparing it with test results,we deduce that the annular permeability lies between 123 and 512 m D.The results help shed light upon assessing the annular pressure in long distance gas flexible pipes and thus ensure the security of gas transport in the emerging development of offshore resources.展开更多
Offshore carbon dioxide(CO_(2)) geological storage(OCGS) represents a significant strategy for addressing climate change by curtailing greenhouse gas emissions. Nonetheless, the risk of CO_(2) leakage poses a substant...Offshore carbon dioxide(CO_(2)) geological storage(OCGS) represents a significant strategy for addressing climate change by curtailing greenhouse gas emissions. Nonetheless, the risk of CO_(2) leakage poses a substantial concern associated with this technology. This study introduces an innovative approach for establishing OCGS leakage scenarios, involving four pivotal stages, namely, interactive matrix establishment, risk matrix evaluation, cause–effect analysis, and scenario development, which has been implemented in the Pearl River Estuary Basin in China. The initial phase encompassed the establishment of an interaction matrix for OCGS systems based on features, events, and processes. Subsequent risk matrix evaluation and cause–effect analysis identified key system components, specifically CO_(2) injection and faults/features. Building upon this analysis, two leakage risk scenarios were successfully developed, accompanied by the corresponding mitigation measures. In addition, this study introduces the application of scenario development to risk assessment, including scenario numerical simulation and quantitative assessment. Overall, this research positively contributes to the sustainable development and safe operation of OCGS projects and holds potential for further refinement and broader application to diverse geographical environments and project requirements. This comprehensive study provides valuable insights into the establishment of OCGS leakage scenarios and demonstrates their practical application to risk assessment, laying the foundation for promoting the sustainable development and safe operation of ocean CO_(2) geological storage projects while proposing possibilities for future improvements and broader applications to different contexts.展开更多
Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,dr...Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,drilling a multilateral well does not always increase the flow rate when compared to two single-horizontal wells due to competition in production inside the mother-bore.Here,a holistic approach is proposed to find the optimum balance between single and multilateral wells in an offshore oil development.In so doing,the integrated approach finds the highest Net Present Value(NPV)configuration of the field considering drilling,subsurface,production and financial analysis.The model employs stochastic perturbation and Markov Chain Monte-Carlo methods to solve the global maximising-NPV problem.In addition,a combination of Mixed-Integer Linear Programming(MILP),an improved Dijkstra algorithm and a Levenberg-Marquardt optimiser is proposed to solve the rate allocation problem.With the outcome from this analysis,the model suggests the optimum development including number of multilateral and single horizontal wells that would result in the highest NPV.The results demonstrate the potential for modelling to find the optimal use of petroleum facilities and to assist with planning and decision making.展开更多
China has a wide sea waters with their offshore continental shelf covering over 1 million km?.Rich oil-gas resources are lying under the sea waters.In accordance with the conventional international assessment method f...China has a wide sea waters with their offshore continental shelf covering over 1 million km?.Rich oil-gas resources are lying under the sea waters.In accordance with the conventional international assessment method for oil and gas resources,it is expected that the gas reserve volume in China is approximately 14000 billion cu.m.Particularly,the Yinggehai Basin,Qiongdo-ngnan Basin and Zhushan Depression in the Pearl River Mouth basin of the South China Sea are rapidly subsiding basins with more than 100 million km2 of prospects for exploration,where the geological conditions are favourable for generation of rich natural gas.展开更多
Baoshan Iron ＆ Steel Co.,Ltd., （referred to as Baosteel） in China first succeeded in developing the U-ing-O- ing-Expanding （UOE） longitudinal submerged arc welded pipes （SAWLs） offshore linepipe of a maximum th...Baoshan Iron ＆ Steel Co.,Ltd., （referred to as Baosteel） in China first succeeded in developing the U-ing-O- ing-Expanding （UOE） longitudinal submerged arc welded pipes （SAWLs） offshore linepipe of a maximum thickness/ outside diameter （T/D） 0.042 in 2011. Described in this paper is the research and development of the X70 UOE SAWL pipes by the company. The result shows that the said X70 linepipe has been in compliance with relevant requirements as specified in Specifications DNV-OS-F101 ,and has been successfully used in the South China Sea deepwater gas pipeline project.展开更多
The west part of the northern continental shelf of the South China Sea lies in the west of the longitude of 113°10'E,consisting of three basins named Yinggehai.Qiongdongnan and Zhu-3 De-pression,covering an a...The west part of the northern continental shelf of the South China Sea lies in the west of the longitude of 113°10'E,consisting of three basins named Yinggehai.Qiongdongnan and Zhu-3 De-pression,covering an area about 18.5X10^(4)km.展开更多
The integrated development of marine ranching and offshore renewable energy is a new development mode of marine industry which develops and uses marine resources intensively and ecologically.China has taken the lead i...The integrated development of marine ranching and offshore renewable energy is a new development mode of marine industry which develops and uses marine resources intensively and ecologically.China has taken the lead in carrying out active exploration,which is of great significance for implementing the concept of green development,seizing the opportunity of Marine economic development and promoting the construction of modern marine ranching.However,in the initial stage of integrated development,in order to ensure sustainable development,it is necessary to focus on the major problems that have emerged or may arise in the areas of ecological protection,technology research and development,financial support and policy support.To solve or prevent these problems,we should strengthen policy toplevel design,policy innovation,international cooperation and first-mover advantage.展开更多
基金supported by the Natural Science Research Project of Guangling College of Yangzhou University,China (ZKZD18004)General Program of Natural Science Research in Higher Education Institutions of Jiangsu Province,China (20KJD430006)。
文摘Gas flexible pipes are critical multi-layered equipment for offshore oil and gas development.Under high pressure conditions,small molecular components of natural gas dissolve into the polymer inner liner of the flexible pipes and further diffuse into the annular space,incurring annular pressure build-up and/or production of acidic environment,which poses serious challenges to the structure and integrity of the flexible pipes.Gas permeation in pipes is a complex phenomenon governed by various factors such as internal pressure and temperature,annular structure,external temperature.In a long-distance gas flexible pipe,moreover,gas permeation exhibits non-uniform features,and the gas permeated into the annular space flows along the metal gap.To assess the complex gas transport behavior in long-distance gas flexible pipes,a mathematical model is established in this paper considering the multiphase flow phenomena inside the flexible pipes,the diffusion of gas in the inner liner,and the gas seepage in the annular space under varying permeable properties of the annulus.In addition,the effect of a variable temperature is accounted.A numerical calculation method is accordingly constructed to solve the coupling mathematical equations.The annular permeability was shown to significantly influence the distribution of annular pressure.As permeability increases,the annular pressure tends to become more uniform,and the annular pressure at the wellhead rises more rapidly.After annular pressure relief followed by shut-in,the pressure increase follows a convex function.By simulating the pressure recovery pattern after pressure relief and comparing it with test results,we deduce that the annular permeability lies between 123 and 512 m D.The results help shed light upon assessing the annular pressure in long distance gas flexible pipes and thus ensure the security of gas transport in the emerging development of offshore resources.
文摘Offshore carbon dioxide(CO_(2)) geological storage(OCGS) represents a significant strategy for addressing climate change by curtailing greenhouse gas emissions. Nonetheless, the risk of CO_(2) leakage poses a substantial concern associated with this technology. This study introduces an innovative approach for establishing OCGS leakage scenarios, involving four pivotal stages, namely, interactive matrix establishment, risk matrix evaluation, cause–effect analysis, and scenario development, which has been implemented in the Pearl River Estuary Basin in China. The initial phase encompassed the establishment of an interaction matrix for OCGS systems based on features, events, and processes. Subsequent risk matrix evaluation and cause–effect analysis identified key system components, specifically CO_(2) injection and faults/features. Building upon this analysis, two leakage risk scenarios were successfully developed, accompanied by the corresponding mitigation measures. In addition, this study introduces the application of scenario development to risk assessment, including scenario numerical simulation and quantitative assessment. Overall, this research positively contributes to the sustainable development and safe operation of OCGS projects and holds potential for further refinement and broader application to diverse geographical environments and project requirements. This comprehensive study provides valuable insights into the establishment of OCGS leakage scenarios and demonstrates their practical application to risk assessment, laying the foundation for promoting the sustainable development and safe operation of ocean CO_(2) geological storage projects while proposing possibilities for future improvements and broader applications to different contexts.
文摘Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,drilling a multilateral well does not always increase the flow rate when compared to two single-horizontal wells due to competition in production inside the mother-bore.Here,a holistic approach is proposed to find the optimum balance between single and multilateral wells in an offshore oil development.In so doing,the integrated approach finds the highest Net Present Value(NPV)configuration of the field considering drilling,subsurface,production and financial analysis.The model employs stochastic perturbation and Markov Chain Monte-Carlo methods to solve the global maximising-NPV problem.In addition,a combination of Mixed-Integer Linear Programming(MILP),an improved Dijkstra algorithm and a Levenberg-Marquardt optimiser is proposed to solve the rate allocation problem.With the outcome from this analysis,the model suggests the optimum development including number of multilateral and single horizontal wells that would result in the highest NPV.The results demonstrate the potential for modelling to find the optimal use of petroleum facilities and to assist with planning and decision making.
文摘China has a wide sea waters with their offshore continental shelf covering over 1 million km?.Rich oil-gas resources are lying under the sea waters.In accordance with the conventional international assessment method for oil and gas resources,it is expected that the gas reserve volume in China is approximately 14000 billion cu.m.Particularly,the Yinggehai Basin,Qiongdo-ngnan Basin and Zhushan Depression in the Pearl River Mouth basin of the South China Sea are rapidly subsiding basins with more than 100 million km2 of prospects for exploration,where the geological conditions are favourable for generation of rich natural gas.
文摘Baoshan Iron ＆ Steel Co.,Ltd., （referred to as Baosteel） in China first succeeded in developing the U-ing-O- ing-Expanding （UOE） longitudinal submerged arc welded pipes （SAWLs） offshore linepipe of a maximum thickness/ outside diameter （T/D） 0.042 in 2011. Described in this paper is the research and development of the X70 UOE SAWL pipes by the company. The result shows that the said X70 linepipe has been in compliance with relevant requirements as specified in Specifications DNV-OS-F101 ,and has been successfully used in the South China Sea deepwater gas pipeline project.
文摘The west part of the northern continental shelf of the South China Sea lies in the west of the longitude of 113°10'E,consisting of three basins named Yinggehai.Qiongdongnan and Zhu-3 De-pression,covering an area about 18.5X10^(4)km.
文摘The integrated development of marine ranching and offshore renewable energy is a new development mode of marine industry which develops and uses marine resources intensively and ecologically.China has taken the lead in carrying out active exploration,which is of great significance for implementing the concept of green development,seizing the opportunity of Marine economic development and promoting the construction of modern marine ranching.However,in the initial stage of integrated development,in order to ensure sustainable development,it is necessary to focus on the major problems that have emerged or may arise in the areas of ecological protection,technology research and development,financial support and policy support.To solve or prevent these problems,we should strengthen policy toplevel design,policy innovation,international cooperation and first-mover advantage.
