目的评价奥赛利定应用于老年全膝关节置换术(TKA)术后患者自控静脉镇痛(PCIA)的效果及安全性。方法采用前瞻性、双盲、单中心、随机对照设计,纳入84例择期全麻下TKA患者,随机分为奥赛利定组与舒芬太尼组(各42例),均行术后48 h PCIA。主...目的评价奥赛利定应用于老年全膝关节置换术(TKA)术后患者自控静脉镇痛(PCIA)的效果及安全性。方法采用前瞻性、双盲、单中心、随机对照设计,纳入84例择期全麻下TKA患者,随机分为奥赛利定组与舒芬太尼组(各42例),均行术后48 h PCIA。主要结局指标为术后24 h静态视觉模拟评分法(VAS)评分,次要结局指标为术后6、12、24、48 h静态和动态VAS评分;术后首次按压PCIA时间、术后48 h内PCIA有效按压次数(D1)、术后48 h内PCIA总按压次数(D2)、D1/D2比值、补救镇痛发生率;拔管后5、10、20、30 min Ramsay镇静评分、术前24 h及术后24、48 h恢复质量量表-15(QoR-15)评分、术前1晚及术后第1、2晚阿森斯失眠量表(AIS)评分、满意度评分、术后住院时间;术后48 h内不良事件发生情况(恶心呕吐、呼吸抑制、尿潴留、头晕等)。结果奥赛利定组与舒芬太尼组所有时间点的VAS评分、Ramsay评分、镇痛泵按压相关指标及补救镇痛发生率比较,差异均无统计学意义(P>0.05)。奥赛利定组D1/D2比值、术后24、48 h QoR-15评分、满意度评分均高于舒芬太尼组(P<0.05),术后第1晚AIS评分、恶心呕吐发生率低于舒芬太尼组(P<0.05)。结论本研究在TKA患者中系统比较了奥赛利定与舒芬太尼作为PCIA用药的镇痛效能及安全性,结果显示奥赛利定不仅镇痛效果与舒芬太尼相当,更在安全性及舒适度等方面具有明显优势,奥赛利定显著降低了术后恶心呕吐发生率,并提升了术后恢复质量、睡眠质量及总体满意度。展开更多
Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea(SCS). In...Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea(SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and overpressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.展开更多
The instability of continental slopes damages marine engineering equipment,such as submarine pipelines,resulting in the generation of tsunamis,which endangers the safety of nearshore personnel.Therefore,research on th...The instability of continental slopes damages marine engineering equipment,such as submarine pipelines,resulting in the generation of tsunamis,which endangers the safety of nearshore personnel.Therefore,research on the instability of continental slopes where submarine landslides usually occur is crucial to the risk evaluation of deepwater drilling.Previous studies were mainly based on simplified 2D and 3D models,which extend the 2D model applied on submarine slopes with complex topography.In this study,a numerical model with bathymetric data from the Qiongdongnan Basin was established.Furthermore,3D slope stability analysis and static and dynamic analyses were conducted.The static analysis found two discussions where slopes are most likely to occur.Through the analysis of different seismic forces,the dynamic result showed that an instability area is added to the two positions where the static analysis is unstable.Topography scatters and transmits seismic waves and controls the accumulation and diffusion of seismic energy.3D calculations and analysis revealed that the direction of slope instability is closely related to terrain inclination,slope,terrain effect,and terrain curvature.Data showed that instability situations could not be derived from a single direction or profile data.Such situations are an important factor in slope stability analysis and are critical to the prediction and evaluation of marine geological disasters.展开更多
More than 90%of natural gas hydrates(hereinafter,hydrate for short)in the South China Sea are non-diagenetic ore bodies,so they cannot be exploited easily by means of the conventional methods.In this paper,the solid f...More than 90%of natural gas hydrates(hereinafter,hydrate for short)in the South China Sea are non-diagenetic ore bodies,so they cannot be exploited easily by means of the conventional methods.In this paper,the solid fluidization method,as one of the revolutionary technologies in efficient exploitation of non-diagenetic natural gas hydrates,was,for the first time,put forward by Academician Zhou Shouwei.And it is successfully applied in the Shenhu Area of the South China Sea based on the technologies,equipment and processes which rely on domestic independent intellectual property rights.During the production test of fluidization,the ore bodies of hydrates are broken by the jet at the bottom hole into fine particles and carried upward by the drilling fluid.When the phase equilibrium state is reached with the increase of temperature and the decrease of pressure affected by the operation parameters,which is different from conventional phase equilibrium state,the hydrates bearing solid particles are decomposed,and consequently liquid-solid flow in the annulus becomes complex gas-liquid-solid multiphase flow.Therefore,it is necessary to optimize the construction parameters design so as to meet the high-level requirements of well control safety.In this paper,the engineering parameters are optimally designed based on the engineering geological characteristics of the target block,combined with the analysis on complex multiphase flow in the wellbore.Then,a theoretical model and a numerical calculation method for the multiphase flow,temperature and pressure of complex media in wellbores and the phase equilibrium and decomposition of natural gas hydrates were established.And the multiphase flow in the wellbore during the production test of fluidization was analyzed under different operating parameters by means of numerical simulation,software emulation and experimental verification.And thus,the design optimization scheme of on-site engineering parameters of production test of marine natural gas hydrate fluidization was prepared.It is pointed out that the diameter of jet fluidization well section shall not be excessively large;and that it is necessary to increase the flow rate and density of drilling fluid and apply wellhead back pressure to ensure the cutting carrying safety and to mitigate well control risks.The results of this basic theoretical study can provide significant support to field operation and improvement of output in production tests.展开更多
Gas hydrate(hereinafter,"hydrate"for short)in the marine environment mostly lies in weakly consolidated sediments,so its undisturbed coring is difficult and costly.In view of this,it is necessary to understa...Gas hydrate(hereinafter,"hydrate"for short)in the marine environment mostly lies in weakly consolidated sediments,so its undisturbed coring is difficult and costly.In view of this,it is necessary to understand the relationship between acoustic properties and elastic mechanical properties of hydrates through laboratory experiments.In this paper,samples of hydrate sediments were prepared indoors.Then,petrophysical experiments were carried out on these samples to measure the electric parameters and acoustic parameters of hydrate sediments.Finally,according to the theory of elasticity,the dynamic elastic mechanical parameters under three axial compressions,three particle sizes and three shale contents were calculated to analyze their effects on the dynamic elastic mechanical parameters of hydrate sediments under different conditions.And the following research results were obtained.First,when the hydrate saturation is in a certain range,it is in a proportional relationship with the elastic parameters of sediments.Second,when the hydrate saturation is constant,the dynamic Young's modulus of hydrate sediments increases,but the Poisson's ratio has little to do with the axial compression as particle sizes(0.125-1.180 mm)and axial compression increase and shale content decreases.Third,a model of the relationship between the elastic parameters and the shale content and axial compression is established.In conclusion,the dynamic elastic mechanical indexes of gas hydrate obtained from the acoustic logging methodology will solve the above difficulties and the research results provide a reference for calculating the mechanical properties of hydrate sediments by use of logging data.展开更多
In the core process of fractured marine gas hydrate(hereinafter referred to as hydrate)particles being transported up to the surface platform by airtight pipeline in the solid fluidization exploitation of marine gas h...In the core process of fractured marine gas hydrate(hereinafter referred to as hydrate)particles being transported up to the surface platform by airtight pipeline in the solid fluidization exploitation of marine gas hydrate reservoirs,influenced by the rising temperature and the dropping pressure,the solid hydrates will decompose and produce a large amount of gas at a certain critical point,causing the liquidesolid two-phase flow in the wellbore to change into complicated gaseliquidesolid multiphase non-equilibrium flow,which further aggravate well control,solid phase transportation and other safety risks.In view of this,the dynamic hydrate decomposition law in the above process was studied in this paper by establishing multiphase wellbore flow mathematical models of wellbore temperature and pressure field,hydrate phase equilibrium,hydrate dynamic decomposition in multiphase riser pipe flow,wellbore multiphase flow coupled hydrate dynamic decomposition,and a numerical calculation method was proposed and verified.The following results were obtained.First,by numerical model analysis,the effects of liquid phase displacement,solid throughput(daily gas production rate)and wellhead back pressure under different construction parameters on multi-phase non-equilibrium pipe flow were obtained.In addition,the field construction guidance measures were put forward based on multiphase non-equilibrium pipe flow characteristics as follows:to properly increase the solid throughput so as to increase the natural gas production,to appropriately increase the liquid-phase displacement and the wellhead back pressure so as to ensure well control safety.This study provides not only a theoretical basis for the prediction of multiphase non-equilibrium pipe flow in the solid fluidization exploitation,but a technical support for the field construction parameter optimization and well control safety.展开更多
Influenced by the low temperature of seawater,non-equilibrium formation of natural gas hydrate(hereinafter referred to as hydrate)in the wellbore of a gas/water-producing well is prominent,which increases the risks of...Influenced by the low temperature of seawater,non-equilibrium formation of natural gas hydrate(hereinafter referred to as hydrate)in the wellbore of a gas/water-producing well is prominent,which increases the risks of safety,such as wellbore blockage.In this paper,a wellbore temperature and pressure distribution model and a theoretical model of non-equilibrium hydrate formation and decomposition in marine gas/water-producing wells in the production process of water-bearing natural gas were established on the basis of the previously established methane hydrate phase equilibrium model and hydrate formation and decomposition dynamics model.Then,numerical simulation calculation was carried out on the basis of finite difference method,and thus a set of risk prediction method for the non-equilibrium hydrate formation(hereinafter referred to as hydrate formation risk prediction method)suitable for the production process of marine gas/water-producing well was developed.On this basis,the reliability of the prediction method was verified by using the data of one certain onshore gas production well LN-X,and then the non-equilibrium hydrate formation and decomposition laws in the wellbore of marine gas/water-producing wells under the influences of different parameters were studied.And the following research results were obtained.First,with the increase of daily gas production or water cut,both the hydrate formation area in the wellbore and the amount of hydrate substances decrease.As a result,wellbore blockage is less likely to happen,which is more favorable for the safe production of marine gas/water-producing wells.Second,the higher the wellhead tubing pressure is,the larger the hydrate formation area in the wellbore is and the greater the amount of hydrate substance is.As a result,the wellbore is blocked more easily,which is more unfavorable for the safe production of marine gas/water-producing wells.Third,even under different sea surface temperatures,the range of hydrate formation area is consistent,and so is the range of hydrate decomposition area.The amount of hydrate substance is only different near the wellhead.The higher the sea surface temperature,the lower the amount of hydrate substance.In conclusion,the proposed hydrate formation risk prediction method is reliable,and the research results can provide theoretical guidance for the safe production management of offshore gas reservoirs.展开更多
文摘目的评价奥赛利定应用于老年全膝关节置换术(TKA)术后患者自控静脉镇痛(PCIA)的效果及安全性。方法采用前瞻性、双盲、单中心、随机对照设计,纳入84例择期全麻下TKA患者,随机分为奥赛利定组与舒芬太尼组(各42例),均行术后48 h PCIA。主要结局指标为术后24 h静态视觉模拟评分法(VAS)评分,次要结局指标为术后6、12、24、48 h静态和动态VAS评分;术后首次按压PCIA时间、术后48 h内PCIA有效按压次数(D1)、术后48 h内PCIA总按压次数(D2)、D1/D2比值、补救镇痛发生率;拔管后5、10、20、30 min Ramsay镇静评分、术前24 h及术后24、48 h恢复质量量表-15(QoR-15)评分、术前1晚及术后第1、2晚阿森斯失眠量表(AIS)评分、满意度评分、术后住院时间;术后48 h内不良事件发生情况(恶心呕吐、呼吸抑制、尿潴留、头晕等)。结果奥赛利定组与舒芬太尼组所有时间点的VAS评分、Ramsay评分、镇痛泵按压相关指标及补救镇痛发生率比较,差异均无统计学意义(P>0.05)。奥赛利定组D1/D2比值、术后24、48 h QoR-15评分、满意度评分均高于舒芬太尼组(P<0.05),术后第1晚AIS评分、恶心呕吐发生率低于舒芬太尼组(P<0.05)。结论本研究在TKA患者中系统比较了奥赛利定与舒芬太尼作为PCIA用药的镇痛效能及安全性,结果显示奥赛利定不仅镇痛效果与舒芬太尼相当,更在安全性及舒适度等方面具有明显优势,奥赛利定显著降低了术后恶心呕吐发生率,并提升了术后恢复质量、睡眠质量及总体满意度。
基金supported by the National Natural Science Foundation of China (Nos. 41576049, 4166 6002)the Key Research Projects of Frontier Science of the Chinese Academy of Sciences (No. QYZDB-SSWSYS025)+1 种基金Qingdao National Laboratory for Marine Science and Technology (No. 2016ASKJ13)Key Science and Technology Foundation of Sanya (Nos. 2017PT 13, 2017PT14)
文摘Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea(SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and overpressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.
基金This study was supported by the National Key Research and Development Program of China(No.2019YFC0312301)the Nation Natural Science Foundation of China(No.U1701245).
文摘The instability of continental slopes damages marine engineering equipment,such as submarine pipelines,resulting in the generation of tsunamis,which endangers the safety of nearshore personnel.Therefore,research on the instability of continental slopes where submarine landslides usually occur is crucial to the risk evaluation of deepwater drilling.Previous studies were mainly based on simplified 2D and 3D models,which extend the 2D model applied on submarine slopes with complex topography.In this study,a numerical model with bathymetric data from the Qiongdongnan Basin was established.Furthermore,3D slope stability analysis and static and dynamic analyses were conducted.The static analysis found two discussions where slopes are most likely to occur.Through the analysis of different seismic forces,the dynamic result showed that an instability area is added to the two positions where the static analysis is unstable.Topography scatters and transmits seismic waves and controls the accumulation and diffusion of seismic energy.3D calculations and analysis revealed that the direction of slope instability is closely related to terrain inclination,slope,terrain effect,and terrain curvature.Data showed that instability situations could not be derived from a single direction or profile data.Such situations are an important factor in slope stability analysis and are critical to the prediction and evaluation of marine geological disasters.
基金Project supported by National Key Research and Development Program“New Technology for Marine Gas Hydrate Fluidization Test”(No.:2016YFC0304008)National Natural Science Foundation of China Key Program“Research on the Theoretical Aspects and Key Issues in Managed Pressure Drilling Measuring and Controlling”(No.:51334003).
文摘More than 90%of natural gas hydrates(hereinafter,hydrate for short)in the South China Sea are non-diagenetic ore bodies,so they cannot be exploited easily by means of the conventional methods.In this paper,the solid fluidization method,as one of the revolutionary technologies in efficient exploitation of non-diagenetic natural gas hydrates,was,for the first time,put forward by Academician Zhou Shouwei.And it is successfully applied in the Shenhu Area of the South China Sea based on the technologies,equipment and processes which rely on domestic independent intellectual property rights.During the production test of fluidization,the ore bodies of hydrates are broken by the jet at the bottom hole into fine particles and carried upward by the drilling fluid.When the phase equilibrium state is reached with the increase of temperature and the decrease of pressure affected by the operation parameters,which is different from conventional phase equilibrium state,the hydrates bearing solid particles are decomposed,and consequently liquid-solid flow in the annulus becomes complex gas-liquid-solid multiphase flow.Therefore,it is necessary to optimize the construction parameters design so as to meet the high-level requirements of well control safety.In this paper,the engineering parameters are optimally designed based on the engineering geological characteristics of the target block,combined with the analysis on complex multiphase flow in the wellbore.Then,a theoretical model and a numerical calculation method for the multiphase flow,temperature and pressure of complex media in wellbores and the phase equilibrium and decomposition of natural gas hydrates were established.And the multiphase flow in the wellbore during the production test of fluidization was analyzed under different operating parameters by means of numerical simulation,software emulation and experimental verification.And thus,the design optimization scheme of on-site engineering parameters of production test of marine natural gas hydrate fluidization was prepared.It is pointed out that the diameter of jet fluidization well section shall not be excessively large;and that it is necessary to increase the flow rate and density of drilling fluid and apply wellhead back pressure to ensure the cutting carrying safety and to mitigate well control risks.The results of this basic theoretical study can provide significant support to field operation and improvement of output in production tests.
基金supported by the National Key R&D Program of China“New technology for solid fluidization testing of marine gas hydrate”(No.:2016YFC0304008).
文摘Gas hydrate(hereinafter,"hydrate"for short)in the marine environment mostly lies in weakly consolidated sediments,so its undisturbed coring is difficult and costly.In view of this,it is necessary to understand the relationship between acoustic properties and elastic mechanical properties of hydrates through laboratory experiments.In this paper,samples of hydrate sediments were prepared indoors.Then,petrophysical experiments were carried out on these samples to measure the electric parameters and acoustic parameters of hydrate sediments.Finally,according to the theory of elasticity,the dynamic elastic mechanical parameters under three axial compressions,three particle sizes and three shale contents were calculated to analyze their effects on the dynamic elastic mechanical parameters of hydrate sediments under different conditions.And the following research results were obtained.First,when the hydrate saturation is in a certain range,it is in a proportional relationship with the elastic parameters of sediments.Second,when the hydrate saturation is constant,the dynamic Young's modulus of hydrate sediments increases,but the Poisson's ratio has little to do with the axial compression as particle sizes(0.125-1.180 mm)and axial compression increase and shale content decreases.Third,a model of the relationship between the elastic parameters and the shale content and axial compression is established.In conclusion,the dynamic elastic mechanical indexes of gas hydrate obtained from the acoustic logging methodology will solve the above difficulties and the research results provide a reference for calculating the mechanical properties of hydrate sediments by use of logging data.
基金Project supported by the National Key R&D Program“New Technology for Marine Hydrate Solid Fluidization Testing”(No.:2016YFC0304008)Strategic Research Project for Medium-and Long-Term Development Strategy Research in China's Engineering Science and Technology“Research on Deep Sea Gas Hydrate Development Strategy for 2035”(No.:2017-ZCQ-5)Key Project of National Natural Science Foundation of China,and“Measurement and Control Theory and Key Issues of Managed Pressure Drilling”(No.:51334003).
文摘In the core process of fractured marine gas hydrate(hereinafter referred to as hydrate)particles being transported up to the surface platform by airtight pipeline in the solid fluidization exploitation of marine gas hydrate reservoirs,influenced by the rising temperature and the dropping pressure,the solid hydrates will decompose and produce a large amount of gas at a certain critical point,causing the liquidesolid two-phase flow in the wellbore to change into complicated gaseliquidesolid multiphase non-equilibrium flow,which further aggravate well control,solid phase transportation and other safety risks.In view of this,the dynamic hydrate decomposition law in the above process was studied in this paper by establishing multiphase wellbore flow mathematical models of wellbore temperature and pressure field,hydrate phase equilibrium,hydrate dynamic decomposition in multiphase riser pipe flow,wellbore multiphase flow coupled hydrate dynamic decomposition,and a numerical calculation method was proposed and verified.The following results were obtained.First,by numerical model analysis,the effects of liquid phase displacement,solid throughput(daily gas production rate)and wellhead back pressure under different construction parameters on multi-phase non-equilibrium pipe flow were obtained.In addition,the field construction guidance measures were put forward based on multiphase non-equilibrium pipe flow characteristics as follows:to properly increase the solid throughput so as to increase the natural gas production,to appropriately increase the liquid-phase displacement and the wellhead back pressure so as to ensure well control safety.This study provides not only a theoretical basis for the prediction of multiphase non-equilibrium pipe flow in the solid fluidization exploitation,but a technical support for the field construction parameter optimization and well control safety.
基金supported by the National Major Research and Development Program Project“Research on Gas-liquid-solid mixed flow and separation technology in deep-sea hydrate production wellbore”(No.2019YFC0312302)“New technology for solid-state fluidization testing of marine hydrate”(No.2016YFC0304008)“Technology and technology of riser inflatable double gradient drilling system”(No.2018YFC0310203).
文摘Influenced by the low temperature of seawater,non-equilibrium formation of natural gas hydrate(hereinafter referred to as hydrate)in the wellbore of a gas/water-producing well is prominent,which increases the risks of safety,such as wellbore blockage.In this paper,a wellbore temperature and pressure distribution model and a theoretical model of non-equilibrium hydrate formation and decomposition in marine gas/water-producing wells in the production process of water-bearing natural gas were established on the basis of the previously established methane hydrate phase equilibrium model and hydrate formation and decomposition dynamics model.Then,numerical simulation calculation was carried out on the basis of finite difference method,and thus a set of risk prediction method for the non-equilibrium hydrate formation(hereinafter referred to as hydrate formation risk prediction method)suitable for the production process of marine gas/water-producing well was developed.On this basis,the reliability of the prediction method was verified by using the data of one certain onshore gas production well LN-X,and then the non-equilibrium hydrate formation and decomposition laws in the wellbore of marine gas/water-producing wells under the influences of different parameters were studied.And the following research results were obtained.First,with the increase of daily gas production or water cut,both the hydrate formation area in the wellbore and the amount of hydrate substances decrease.As a result,wellbore blockage is less likely to happen,which is more favorable for the safe production of marine gas/water-producing wells.Second,the higher the wellhead tubing pressure is,the larger the hydrate formation area in the wellbore is and the greater the amount of hydrate substance is.As a result,the wellbore is blocked more easily,which is more unfavorable for the safe production of marine gas/water-producing wells.Third,even under different sea surface temperatures,the range of hydrate formation area is consistent,and so is the range of hydrate decomposition area.The amount of hydrate substance is only different near the wellhead.The higher the sea surface temperature,the lower the amount of hydrate substance.In conclusion,the proposed hydrate formation risk prediction method is reliable,and the research results can provide theoretical guidance for the safe production management of offshore gas reservoirs.
