塔式立管气液两相流的压力波动特性试验研究
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摘要
为了研究深水油气田塔式立管系统气液两相流压力波动特性,通过室内试验分析了不同流型下的压力变化特征、压力波动幅值等。室内试验得到了6种流型,每种流型对应特定的压力波动形式,且最大波动幅度出现在严重段塞流向稳定流转变过程中的过渡流型Ⅱ上。通过分析立管底部的最大、最小压力,得出如下规律:压力波动幅值随折算气速的增加呈现先增大后减小的趋势,且流型的转变对气速的敏感性高于液速。通过概率密度函数(Probability Density Function,PDF)和累计分布函数(Cumulative Distribution Function,CDF)的统计学分析,得出系统压力的PDF和CDF曲线在各种流型下的分布形态:下倾管底部压力PDF曲线在严重段塞流下高压区单峰特征显著;过渡流型下左右两峰相当,呈两端高、中间低的形态;稳定流型下峰值数量增加、压力范围集中;CDF曲线在高压区的拐点与PDF曲线的峰值对应。跨接管底部压力PDF曲线峰值均处于低压区,且中间高、两端低。在严重段塞流下,曲线呈现双峰和三峰分布,稳定流表现为单峰对称分布。结合压力PDF和CDF曲线可辅助分析和判别流型,并直观获得塔式立管系统压力概率分布特征,以此作为其疲劳损坏和安全评估的参考依据。(图8,表1,参21)
In order to investigate the pressure fluctuation characteristics of gas-liquid two-phase flow in the hybrid tower riser system in deep-water oil and gas fields, an indoor test was carried out in this paper to analyze the varying characteristics,amplitude fluctuation and other characteristics of pressure in different flow patterns. In the test, six flow patterns were identified.Each flow pattern is corresponding to the specific pressure fluctuating pattern, and the maximum fluctuating amplitude occurs in the transitional flow pattern Ⅱ during the transform from the severe slugging flow to stable flow. It is shown that the pressure fluctuation amplitude increases firstly and then decreases with the increase of the superficial gas velocity by analyzing the maximum and minimum pressures at the bottom of the riser, and the change of flow pattern is more sensitive to gas velocity than liquid velocity. The pressure distribution characteristics under different flow patterns were obtained based on the statistical analysis of Probability Density Function(PDF) and Cumulative Distribution Function(CDF). In the working condition of severe slugging,the PDF curve for the pressure at the bottom of the downward inclined pipeline presents the remarkable characteristic of single peak in the high pressure zone, that in the transitional flow pattern has two equal peaks at the right and the left sides in the form of high in both ends and low in the middle, and that in the stable flow pattern has more peaks with a narrow range of pressure. The turning point of CDF in the high pressure zone corresponds to the peak of the PDF curve. The peaks of the PDF curves for the pressure at the bottom of the jumper pipe are in the range of low pressure zone and they are high in the middle and low in both ends. The PDF curves present two or three peaks in the working condition of severe slugging and a single symmetrical peak in the pattern of stable flow. In conclusion, combined with PDF and CDF curves of pipeline pressure, flow patterns can be discriminated and analyzed, and the system pressure probability distribution characteristics can be attained intuitively, so as to provide the important basis for the fatigue damage and safety assessment of pipelines.(8 Figures, 1 Table, 21 References)
In order to investigate the pressure fluctuation characteristics of gas-liquid two-phase flow in the hybrid tower riser system in deep-water oil and gas fields, an indoor test was carried out in this paper to analyze the varying characteristics,amplitude fluctuation and other characteristics of pressure in different flow patterns. In the test, six flow patterns were identified.Each flow pattern is corresponding to the specific pressure fluctuating pattern, and the maximum fluctuating amplitude occurs in the transitional flow pattern Ⅱ during the transform from the severe slugging flow to stable flow. It is shown that the pressure fluctuation amplitude increases firstly and then decreases with the increase of the superficial gas velocity by analyzing the maximum and minimum pressures at the bottom of the riser, and the change of flow pattern is more sensitive to gas velocity than liquid velocity. The pressure distribution characteristics under different flow patterns were obtained based on the statistical analysis of Probability Density Function(PDF) and Cumulative Distribution Function(CDF). In the working condition of severe slugging,the PDF curve for the pressure at the bottom of the downward inclined pipeline presents the remarkable characteristic of single peak in the high pressure zone, that in the transitional flow pattern has two equal peaks at the right and the left sides in the form of high in both ends and low in the middle, and that in the stable flow pattern has more peaks with a narrow range of pressure. The turning point of CDF in the high pressure zone corresponds to the peak of the PDF curve. The peaks of the PDF curves for the pressure at the bottom of the jumper pipe are in the range of low pressure zone and they are high in the middle and low in both ends. The PDF curves present two or three peaks in the working condition of severe slugging and a single symmetrical peak in the pattern of stable flow. In conclusion, combined with PDF and CDF curves of pipeline pressure, flow patterns can be discriminated and analyzed, and the system pressure probability distribution characteristics can be attained intuitively, so as to provide the important basis for the fatigue damage and safety assessment of pipelines.(8 Figures, 1 Table, 21 References)
引文
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[12]XIE C,GUO L,LI W,et al.The influence of backpressure on severe slugging in multiphase flow pipeline-riser systems[J].Chemical Engineering Science,2017,163:68-82.
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[14]BALI?O J L.Modeling and simulation of severe slugging in air-water systems including inertial effects[J].Journal of Computational Science,2014,5(3):482-495.
[15]AZEVEDO G R,BALI?O J L,BURR K P.Linear stability analysis for severe slugging in air-water systems considering different mitigation mechanisms[J].International Journal of Multiphase Flow,2015,73:238-250.
[16]SMITH I E,NYDAL O J.The effect of boundary conditions and droplet entrainment on severe slugging using a Lagrangian slug tracking model[J].International Journal of Multiphase Flow,2016,85:245-257.
[17]TAITEL Y,SIMKHIS M,TEVELEV A,et al.Transient gas liquid flow in hilly terrain pipelines[J].International Journal of Multiphase Flow,2016,86:21-27.
[18]ZHANG Z,TAO L.Multiphase transient slugging flow in subsea oil and gas production[C].Busan:ASME 35th International Conference on Ocean,Offshore and Arctic Engineering,2016:1-12.
[19]TANDOH H,CAO Y,AVILA C.Stability of severe slug flow in U-shape riser[C].Colchester:2016 22nd International Conference on Automation and Computing(ICAC),2016:372-377.
[20]LI Q,GUO L,YAO H,et al.The experimental study and real time forcast-control method of the severe slug flow in offshore production riser[C].Calgary:ASME 7th International Pipeline Conference,2008:135-141.
[21]王权,李玉星,胡其会,等.大倾角上倾管气液两相流动特性[J].化工进展,2017,36(8):2822-2829.WANG Q,LI Y X,HU Q H,et al.Characteristics on gas-liquid two-phase flow in large inclination upward pipe[J].Chemical Industry and Engineering Progress,2017,36(8):2822-2829.
[2]王波,何宁,陈国龙.深水油气田开发中的混合立管[J].中国海洋平台,2013,28(1):46-51.WANG B,HE N,CHEN G L.Hybrid riser for deepwater oil&gas field development[J].China Offshore Platform,2013,28(1):46-51.
[3]MOKHATAB S.Severe slugging in a catenary-shaped riser:experimental and simulation studies[J].Petroleum Science&Technology,2007,25(6):719-740.
[4]JIAN S,JUNIOR O,VILANI J,et al.Severe slugging in catenary risers-simplified modeling[C].Riode Janeiro:Offshore Technology Conference,2013:1-16.
[5]高嵩,李巍,尤云祥,等.气液混输悬链线立管系统两相流特性实验[J].力学学报,2012,44(1):71-81.GAO S,LI W,YOU Y X,et al.Experiments on two-phase flow characteristics in a catenary riser system with the gas and liquid mixture transportation[J].Chinese Journal of Theoretical and Applied Mechanics,2012,44(1):71-81.
[6]MONTGOMERY J A.Severe slugging and unstable flows in an S-shaped riser[D].Bedfordshire:Cranfield University,2002:164-168.
[7]MOKHATAB S,TOWLER B F.Severe slugging in flexible risers:review of experimental investigations and OLGApredictions[J].Petroleum Science and Technology,2007,25(7):867-880.
[8]PARK S,NYDAL O J.Study on severe slugging in an S-shaped riser:small-scale experiments compared with simulations[J].Oil and Gas Facilities,2014,3(4):72-80.
[9]彭明,邓道明,李晓平,等.混合立管系统严重段塞流流动特性的实验研究[J].天然气工业,2011,31(11):83-87.PENG M,DENG D M,LI X P,et al.An experimental study of severe slugging in pipeline/hybrid riser systems[J].Natural Gas Industry,2011,31(11):83-87.
[10]王平,宫敬,李清平,等.柔性管段对立管严重段塞流特性的影响[J].石油学报,2013,34(2):380-385.WANG P,GONG J,LI Q P,et al.Influence of the flexible pipe on characteristics of severe slugging in the riser system[J].Acta Petrolei Sinica,2013,34(2):380-385.
[11]GONG J,YANG Z,MA L,et al.Severe slugging in air-water hybrid riser system[J].Advances in Mechanical Engineering,2014:1-10.
[12]XIE C,GUO L,LI W,et al.The influence of backpressure on severe slugging in multiphase flow pipeline-riser systems[J].Chemical Engineering Science,2017,163:68-82.
[13]AZEVEDO G R,BALI?O J L,BURR K P.Influence of pipeline modeling in stability analysis for severe slugging[J].Chemical Engineering Science,2017,161:1-13.
[14]BALI?O J L.Modeling and simulation of severe slugging in air-water systems including inertial effects[J].Journal of Computational Science,2014,5(3):482-495.
[15]AZEVEDO G R,BALI?O J L,BURR K P.Linear stability analysis for severe slugging in air-water systems considering different mitigation mechanisms[J].International Journal of Multiphase Flow,2015,73:238-250.
[16]SMITH I E,NYDAL O J.The effect of boundary conditions and droplet entrainment on severe slugging using a Lagrangian slug tracking model[J].International Journal of Multiphase Flow,2016,85:245-257.
[17]TAITEL Y,SIMKHIS M,TEVELEV A,et al.Transient gas liquid flow in hilly terrain pipelines[J].International Journal of Multiphase Flow,2016,86:21-27.
[18]ZHANG Z,TAO L.Multiphase transient slugging flow in subsea oil and gas production[C].Busan:ASME 35th International Conference on Ocean,Offshore and Arctic Engineering,2016:1-12.
[19]TANDOH H,CAO Y,AVILA C.Stability of severe slug flow in U-shape riser[C].Colchester:2016 22nd International Conference on Automation and Computing(ICAC),2016:372-377.
[20]LI Q,GUO L,YAO H,et al.The experimental study and real time forcast-control method of the severe slug flow in offshore production riser[C].Calgary:ASME 7th International Pipeline Conference,2008:135-141.
[21]王权,李玉星,胡其会,等.大倾角上倾管气液两相流动特性[J].化工进展,2017,36(8):2822-2829.WANG Q,LI Y X,HU Q H,et al.Characteristics on gas-liquid two-phase flow in large inclination upward pipe[J].Chemical Industry and Engineering Progress,2017,36(8):2822-2829.