含蜡原油乳状液凝胶结构裂降行为模型
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摘要
在常温或深海低温条件下,含蜡原油与水形成的W/O型乳状液易发生胶凝,容易对管道再启动安全性造成威胁。基于含蜡原油乳状液凝胶复杂的流变行为,分别探讨黏塑性和黏弹性两类含蜡原油触变模型对其乳状液凝胶的适用性。通过对比目前常用于含蜡原油的4种黏塑性触变模型,以及近期发展的黏弹性触变模型,筛选出能够准确描述乳状液凝胶加载后整个流变响应过程的模型。通过实验数据拟合发现,滕厚兴提出的黏弹性触变模型对包括屈服前蠕变和屈服后裂降的整个过程的描述最准确;在黏塑性触变模型中,滕厚兴提出的黏塑性模型对屈服点后裂降过程的描述结果偏差最小,而传统的Houska黏塑性模型对乳状液凝胶裂降过程的描述效果不佳,主要是由于该模型的速率方程与实际裂降过程不符。由于黏塑性触变模型无法描述屈服点之前的黏弹性响应,因此推荐采用滕厚兴的黏弹性触变模型进行管道再启动计算。
Under atmospheric temperature or deep sea low temperature, W/O emulsion composed of waxy crude oil and water tends to gelatinize, threatening the restart safety of pipelines. Based on the complex rheological properties of waxy crude oil emulsion gel, two kinds of thixotropic models proposed for waxy crude oil(i.e., the viscoplastic thixotropy model and the viscoelastic thixotropy model) were investigated in terms of their applicability to the emulsion gels. The rheological model that could accurately describe the whole rheological response process after the adding of emulsion gel was selected by comparing four viscoplasticity models which are commonly used for waxy crude oil and the viscoelasticity models which are developed recently. The experimental data fitting results show that the viscoelasticity model developed by Teng Houxing provides the most accurate description on the whole rheological response, including the creep before the yielding and the breakdown after the yielding. Among all viscoplastic thixotropy models, the one developed by Teng Houxing is the least deviated in the description of breakdown process after the yielding point, while the traditional Houska model can not describe the breakdown process of emulsion gel properly mainly because its rate equation can not reflect the actual breakdown process accurately. To sum up, the viscoplastic thixotropy models can not describe the viscoelastic response before the yielding point, so it is recommended to adopt the viscoelastic thixotropy model developed by Teng to perform pipeline restart calculation.
Under atmospheric temperature or deep sea low temperature, W/O emulsion composed of waxy crude oil and water tends to gelatinize, threatening the restart safety of pipelines. Based on the complex rheological properties of waxy crude oil emulsion gel, two kinds of thixotropic models proposed for waxy crude oil(i.e., the viscoplastic thixotropy model and the viscoelastic thixotropy model) were investigated in terms of their applicability to the emulsion gels. The rheological model that could accurately describe the whole rheological response process after the adding of emulsion gel was selected by comparing four viscoplasticity models which are commonly used for waxy crude oil and the viscoelasticity models which are developed recently. The experimental data fitting results show that the viscoelasticity model developed by Teng Houxing provides the most accurate description on the whole rheological response, including the creep before the yielding and the breakdown after the yielding. Among all viscoplastic thixotropy models, the one developed by Teng Houxing is the least deviated in the description of breakdown process after the yielding point, while the traditional Houska model can not describe the breakdown process of emulsion gel properly mainly because its rate equation can not reflect the actual breakdown process accurately. To sum up, the viscoplastic thixotropy models can not describe the viscoelastic response before the yielding point, so it is recommended to adopt the viscoelastic thixotropy model developed by Teng to perform pipeline restart calculation.
引文
[1]CHANG C,NGUYEN Q D,R?NNINGSEN H P.Isothermal start-up of pipeline transporting waxy crude oil[J].Journal of Non-Newtonian Fluid Mechanics,1999,87(2):127-154.
[2]CHILINGARIAN G V,ROBERTSON J O,KUMAR S.Surface operations in petroleum production[M].New York:Elsevier Science Publication Co.Inc.,1987:2-3.
[3]GHOSH S,PRADHAN M,PATEL T,et al.Long-term stability of crystal-stabilized water-in-oil emulsions[J].Journal of Colloid and Interface Science,2015,460:247-257.
[4]VISINTIN R F G,LOCKHART T P,LAPASIN R,et al.Structure of waxy crude oil emulsion gels[J].Journal of NonNewtonian Fluid Mechanics,2008,149(1):34-39.
[5]SUN G Y,ZHANG J J,LI H Y.Structural behaviors of waxy crude oil emulsion gels[J].Energy&Fuels,2014,28(6):3718-3729.
[6]孙广宇,张劲军.W/O型原油乳状液及其凝胶流变特性研究进展[J].油气储运,2016,35(3):229-240.SUN G Y,ZHANG J J.Progress in rheological studies of W/Oemulsion and its gel[J].Oil&Gas Storage and Transportation,2016,35(3):229-240.
[7]HAJ-SHAFIEI S,GHOSH S,ROUSSEAU D.Kinetic stability and rheology of wax-stabilized water-in-oil emulsions at different water cuts[J].Journal of Colloid and Interface Science,2013,410:11-20.
[8]黄启玉,王蕾.微观液滴分布对含蜡原油乳状液流变性的影响[J].石油学报,2013,34(4):765-774.HUANG Q Y,WANG L.Effect of droplet distribution on rheological properties of water-in-oil emulsion in waxy crude oils[J].Acta Petrolei Sinica,2013,34(4):765-774.
[9]王玮,宫敬,李晓平.非牛顿稠油包水乳状液的剪切稀释性[J].石油学报,2010,31(6):1024-1026.WANG W,GONG J,LI X P.Shear thinning behaviors of nonNewtonian water-in-heavy-oil emulsions[J].Acta Petrolei Sinica,2010,31(6):1024-1026.
[10]SUN G Y,ZHANG J J.Structural breakdown and recovery of waxy crude oil emulsion gels[J].Rheologica Acta,2015,54(9-10):817-829.
[11]GUO L P,ZHANG J J,SUN G Y,et al.Thixotropy and its estimation of water-in-waxy crude emulsion gels[J].Journal of Petroleum Science and Engineering,2015,131:86-95.
[12]国丽萍,张劲军.含蜡原油乳状液触变性研究[J].工程热物理学报,2009,30(2):246-248.GUO L P,ZHANG J J.Study on thixotropy of waxy crude oil emulsion[J].Journal of Engineering Thermophysics,2009,30(2):246-248.
[13]YAN D F,LUO Z M.Rheological properties of Daqing crude oil and their application in pipeline transportation[J].SPEProduction Engineering,1987,2(4):267-276.
[14]KANéM,DJABOUROV M,VOLLE J L.Rheology and structure of waxy crude oils in quiescent and under shearing conditions[J].Fuel,2004,83(11):1591-1605.
[15]NGUYEN Q D,BOGER D V.Thixotropic behaviour of concentrated bauxite residue suspensions[J].Rheologica Acta,1985,24(4):427-437.
[16]DEKRETSER R G,BOGER D V.A structural model for the time-dependent recovery of mineral suspensions[J].Rheologica Acta,2001,40(6):582-590.
[17]MEWIS J,WAGNER N J.Thixotropy[J].Advances in Colloid and Interface Science,2009,147-148:214-227.
[18]ROUSSEL N.A thixotropy model for fresh fluid concretes:Theory,validation and applications[J].Cement and Concrete Research,2006,36(10):1797-1806.
[19]V I N A Y G,W A C H S A,A G A S S A N T J F.N u m e r i c a l simulation of non-isothermal viscoplastic waxy crude oil flows[J].Journal of Non-Newtonian Fluid Mechanics,2005,128(2):144-162.
[20]DAVIDSON M R,NGUYEN Q D,R?NNINGSEN H P.Restart model for a multi-plug gelled waxy oil pipeline[J].Journal of Petroleum Science and Engineering,2007,59(1):1-16.
[21]VINAY G,WACHS A,FRIGAARD I.Start-up transients and efficient computation of isothermal waxy crude oil flows[J].Journal of Non-Newtonian Fluid Mechanics,2007,143(2):141-156.
[22]滕厚兴,张劲军.含蜡原油触变模型研究现状[J].油气储运,2013,32(9):923-938.TENG H X,ZHANG J J.Review of the thixotropic models for waxy crude[J].Oil&Gas Storage and Transportation,2013,32(9):923-938.
[23]B U R G O S G R,A L E X A N D R O U A N,E N T O V V.Thixotropic rheology of semisolid metal suspensions[J].Journal of Materials Processing Technology,2001,110(2):164-176.
[24]CAWKWELL M G,CHARLES M E.Characterization of Canadian arctic thixotropic gelled crude oils utilizing an eightparameter model[J].Journal of Pipelines,1989,7:251-264.
[25]CROSS M M.Rheology of non-Newtonian fluids:A new flow equation for pseudoplastic systems[J].Journal of Colloid Science,1965,20(5):417-437.
[26]GUO L P,ZHANG J J,HAN S P,et al.Evaluation of thixotropic models for waxy crudes based on stepwise shearing measurements[J].Petroleum Science and Technology,2013,31(9):895-901.
[27]HOUSKA M.Engineering aspects of the rheology of thixotropic liquids[D].Prague:Czech Techincal University of Prague,1981:47-83.
[28]MOORE F.The rheology of ceramic slips and bodies[J].Transactions of the British Ceramic Society,1959,58:470-494.
[29]WORRALL W,ETULIANI S.Viscosity changes during the ageing of clay-water suspensions[J].Transactions of the British Ceramic Society,1964,63:167-185.
[30]贾邦龙,张劲军.六参数含蜡原油触变模型[J].石油学报,2012,33(6):1080-1085.JIA B L,ZHANG J J.A six-parameter thixotropic model for waxy crude oil[J].Acta Petrolei Sinica,2012,33(6):1080-1085.
[31]WACHS A,VINAY G,FRIGAARD I.A 1.5D numerical model for the start up of weakly compressible flow of a viscoplastic and thixotropic fluid in pipelines[J].Journal of Non-Newtonian Fluid Mechanics,2009,159(1):81-94.
[32]AHMADPOUR A,SADEGHY K,MADDAH-SADATIEHS R.The effect of a variable plastic viscosity on the restart problem of pipelines filled with gelled waxy crude oils[J].Journal of Non-Newtonian Fluid Mechanics,2014,205:16-27.
[33]ZHANG J J,GUO L P,TENG H X.Evaluation of thixotropic models for waxy crude oils based on shear stress decay at constant shear rates[J].Applied Rheology,2010,20(5):53944-53950.
[34]TENG H X,ZHANG J J.A new thixotropic model for waxy crude[J].Rheologica Act,2013,52(10-12):903-911.
[35]赵晓东.改性原油输送管道启动过程非稳态水力、热力计算方法研究[D].北京:中国石油大学(北京),1999:42-61.ZHthermalcomputation of the restart process of the PPD-beneficiated crude oil pipeline[D].Beijing:China University of Petroleum(Beijing),1999:42-61.
[36]PAULO D S.Modeling the thixotropic behavior of structured fluids[J].Journal of Non-Newtonian Fluid Mechanics,2009,164(1):66-75.
[37]PAULO D E S M.Thixotropic elasto-viscoplastic model for structured fluids[J].Soft Matter,2011,7(6):2471-2483.
[38]PAULO D E S M,THOMPSON R L.A critical overview of elasto-viscoplastic thixotropic modeling[J].Journal of NonNewtonian Fluid Mechanics,2012,187-188:8-15.
[39]PAULO D E S M,THOMPSON R L.A unified approach to model elasto-viscoplastic thixotropic yield-stress materials and apparent yield-stress fluids[J].Rheologica Acta,2013,52(7):673-694.
[40]DORAISWAMY D,MUJUMDAR A N,TSAO I,et al.The Cox-Merz rule extended:A rheological model for concentrated suspensions and other materials with a yield stress[J].Journal of Rheology,1991,35(4):647-685.
[41]DULLAERT K,MEWIS J.A structural kinetics model for thixotropy[J].Journal of Non-Newtonian Fluid Mechanics,2006,139(1):21-30.
[42]FANG B,JIANG T Q.A novel constitutive equation for viscoelastic-thixotropic fluids and its application in the characterization of blood hysteresis loop[J].Chinese Journal of Chemical Engineering,1998,6(3):264-270.
[43]HUANG S,LU C.The characterization of the time-dependent nonlinear viscoelastic of an LDPE melt using a simple thixotropy model[J].Acta Mechanica Sinica,2005,21(4):330-335.
[44]LABANDA J,MARCO P,LLORENS J.Rheological model to predict the thixotropic behaviour of colloidal dispersions[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects,2004,249(1):123-126.
[45]LABANDA J,LLORENS J.A structural model for thixotropy of colloidal dispersions[J].Rheologica Acta,2006,45(3):305-314.
[46]MUJUMDAR A,BERIS A N,METZNER A B.Transient phenomena in thixotropic systems[J].Journal of NonNewtonian Fluid Mechanics,2002,102(2):157-178.
[47]TENG H,ZHANG J J.Modeling the viscoelasto-plastic behavior of waxy crude[J].Petroleum Science,2013,10(3):395-401.
[48]TENG H X,ZHANG J J.Modeling the thixotropic behavior of waxy crude[J].Industrial&Engineering Chemistry Research,2013,52(23):8079-8089.
[49]ZHU C,SMAY J E.Thixotropic rheology of concentrated alumina colloidal gels for solid freeform fabrication[J].Journal of Rheology,2011,55(3):655-672.
[2]CHILINGARIAN G V,ROBERTSON J O,KUMAR S.Surface operations in petroleum production[M].New York:Elsevier Science Publication Co.Inc.,1987:2-3.
[3]GHOSH S,PRADHAN M,PATEL T,et al.Long-term stability of crystal-stabilized water-in-oil emulsions[J].Journal of Colloid and Interface Science,2015,460:247-257.
[4]VISINTIN R F G,LOCKHART T P,LAPASIN R,et al.Structure of waxy crude oil emulsion gels[J].Journal of NonNewtonian Fluid Mechanics,2008,149(1):34-39.
[5]SUN G Y,ZHANG J J,LI H Y.Structural behaviors of waxy crude oil emulsion gels[J].Energy&Fuels,2014,28(6):3718-3729.
[6]孙广宇,张劲军.W/O型原油乳状液及其凝胶流变特性研究进展[J].油气储运,2016,35(3):229-240.SUN G Y,ZHANG J J.Progress in rheological studies of W/Oemulsion and its gel[J].Oil&Gas Storage and Transportation,2016,35(3):229-240.
[7]HAJ-SHAFIEI S,GHOSH S,ROUSSEAU D.Kinetic stability and rheology of wax-stabilized water-in-oil emulsions at different water cuts[J].Journal of Colloid and Interface Science,2013,410:11-20.
[8]黄启玉,王蕾.微观液滴分布对含蜡原油乳状液流变性的影响[J].石油学报,2013,34(4):765-774.HUANG Q Y,WANG L.Effect of droplet distribution on rheological properties of water-in-oil emulsion in waxy crude oils[J].Acta Petrolei Sinica,2013,34(4):765-774.
[9]王玮,宫敬,李晓平.非牛顿稠油包水乳状液的剪切稀释性[J].石油学报,2010,31(6):1024-1026.WANG W,GONG J,LI X P.Shear thinning behaviors of nonNewtonian water-in-heavy-oil emulsions[J].Acta Petrolei Sinica,2010,31(6):1024-1026.
[10]SUN G Y,ZHANG J J.Structural breakdown and recovery of waxy crude oil emulsion gels[J].Rheologica Acta,2015,54(9-10):817-829.
[11]GUO L P,ZHANG J J,SUN G Y,et al.Thixotropy and its estimation of water-in-waxy crude emulsion gels[J].Journal of Petroleum Science and Engineering,2015,131:86-95.
[12]国丽萍,张劲军.含蜡原油乳状液触变性研究[J].工程热物理学报,2009,30(2):246-248.GUO L P,ZHANG J J.Study on thixotropy of waxy crude oil emulsion[J].Journal of Engineering Thermophysics,2009,30(2):246-248.
[13]YAN D F,LUO Z M.Rheological properties of Daqing crude oil and their application in pipeline transportation[J].SPEProduction Engineering,1987,2(4):267-276.
[14]KANéM,DJABOUROV M,VOLLE J L.Rheology and structure of waxy crude oils in quiescent and under shearing conditions[J].Fuel,2004,83(11):1591-1605.
[15]NGUYEN Q D,BOGER D V.Thixotropic behaviour of concentrated bauxite residue suspensions[J].Rheologica Acta,1985,24(4):427-437.
[16]DEKRETSER R G,BOGER D V.A structural model for the time-dependent recovery of mineral suspensions[J].Rheologica Acta,2001,40(6):582-590.
[17]MEWIS J,WAGNER N J.Thixotropy[J].Advances in Colloid and Interface Science,2009,147-148:214-227.
[18]ROUSSEL N.A thixotropy model for fresh fluid concretes:Theory,validation and applications[J].Cement and Concrete Research,2006,36(10):1797-1806.
[19]V I N A Y G,W A C H S A,A G A S S A N T J F.N u m e r i c a l simulation of non-isothermal viscoplastic waxy crude oil flows[J].Journal of Non-Newtonian Fluid Mechanics,2005,128(2):144-162.
[20]DAVIDSON M R,NGUYEN Q D,R?NNINGSEN H P.Restart model for a multi-plug gelled waxy oil pipeline[J].Journal of Petroleum Science and Engineering,2007,59(1):1-16.
[21]VINAY G,WACHS A,FRIGAARD I.Start-up transients and efficient computation of isothermal waxy crude oil flows[J].Journal of Non-Newtonian Fluid Mechanics,2007,143(2):141-156.
[22]滕厚兴,张劲军.含蜡原油触变模型研究现状[J].油气储运,2013,32(9):923-938.TENG H X,ZHANG J J.Review of the thixotropic models for waxy crude[J].Oil&Gas Storage and Transportation,2013,32(9):923-938.
[23]B U R G O S G R,A L E X A N D R O U A N,E N T O V V.Thixotropic rheology of semisolid metal suspensions[J].Journal of Materials Processing Technology,2001,110(2):164-176.
[24]CAWKWELL M G,CHARLES M E.Characterization of Canadian arctic thixotropic gelled crude oils utilizing an eightparameter model[J].Journal of Pipelines,1989,7:251-264.
[25]CROSS M M.Rheology of non-Newtonian fluids:A new flow equation for pseudoplastic systems[J].Journal of Colloid Science,1965,20(5):417-437.
[26]GUO L P,ZHANG J J,HAN S P,et al.Evaluation of thixotropic models for waxy crudes based on stepwise shearing measurements[J].Petroleum Science and Technology,2013,31(9):895-901.
[27]HOUSKA M.Engineering aspects of the rheology of thixotropic liquids[D].Prague:Czech Techincal University of Prague,1981:47-83.
[28]MOORE F.The rheology of ceramic slips and bodies[J].Transactions of the British Ceramic Society,1959,58:470-494.
[29]WORRALL W,ETULIANI S.Viscosity changes during the ageing of clay-water suspensions[J].Transactions of the British Ceramic Society,1964,63:167-185.
[30]贾邦龙,张劲军.六参数含蜡原油触变模型[J].石油学报,2012,33(6):1080-1085.JIA B L,ZHANG J J.A six-parameter thixotropic model for waxy crude oil[J].Acta Petrolei Sinica,2012,33(6):1080-1085.
[31]WACHS A,VINAY G,FRIGAARD I.A 1.5D numerical model for the start up of weakly compressible flow of a viscoplastic and thixotropic fluid in pipelines[J].Journal of Non-Newtonian Fluid Mechanics,2009,159(1):81-94.
[32]AHMADPOUR A,SADEGHY K,MADDAH-SADATIEHS R.The effect of a variable plastic viscosity on the restart problem of pipelines filled with gelled waxy crude oils[J].Journal of Non-Newtonian Fluid Mechanics,2014,205:16-27.
[33]ZHANG J J,GUO L P,TENG H X.Evaluation of thixotropic models for waxy crude oils based on shear stress decay at constant shear rates[J].Applied Rheology,2010,20(5):53944-53950.
[34]TENG H X,ZHANG J J.A new thixotropic model for waxy crude[J].Rheologica Act,2013,52(10-12):903-911.
[35]赵晓东.改性原油输送管道启动过程非稳态水力、热力计算方法研究[D].北京:中国石油大学(北京),1999:42-61.ZHthermalcomputation of the restart process of the PPD-beneficiated crude oil pipeline[D].Beijing:China University of Petroleum(Beijing),1999:42-61.
[36]PAULO D S.Modeling the thixotropic behavior of structured fluids[J].Journal of Non-Newtonian Fluid Mechanics,2009,164(1):66-75.
[37]PAULO D E S M.Thixotropic elasto-viscoplastic model for structured fluids[J].Soft Matter,2011,7(6):2471-2483.
[38]PAULO D E S M,THOMPSON R L.A critical overview of elasto-viscoplastic thixotropic modeling[J].Journal of NonNewtonian Fluid Mechanics,2012,187-188:8-15.
[39]PAULO D E S M,THOMPSON R L.A unified approach to model elasto-viscoplastic thixotropic yield-stress materials and apparent yield-stress fluids[J].Rheologica Acta,2013,52(7):673-694.
[40]DORAISWAMY D,MUJUMDAR A N,TSAO I,et al.The Cox-Merz rule extended:A rheological model for concentrated suspensions and other materials with a yield stress[J].Journal of Rheology,1991,35(4):647-685.
[41]DULLAERT K,MEWIS J.A structural kinetics model for thixotropy[J].Journal of Non-Newtonian Fluid Mechanics,2006,139(1):21-30.
[42]FANG B,JIANG T Q.A novel constitutive equation for viscoelastic-thixotropic fluids and its application in the characterization of blood hysteresis loop[J].Chinese Journal of Chemical Engineering,1998,6(3):264-270.
[43]HUANG S,LU C.The characterization of the time-dependent nonlinear viscoelastic of an LDPE melt using a simple thixotropy model[J].Acta Mechanica Sinica,2005,21(4):330-335.
[44]LABANDA J,MARCO P,LLORENS J.Rheological model to predict the thixotropic behaviour of colloidal dispersions[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects,2004,249(1):123-126.
[45]LABANDA J,LLORENS J.A structural model for thixotropy of colloidal dispersions[J].Rheologica Acta,2006,45(3):305-314.
[46]MUJUMDAR A,BERIS A N,METZNER A B.Transient phenomena in thixotropic systems[J].Journal of NonNewtonian Fluid Mechanics,2002,102(2):157-178.
[47]TENG H,ZHANG J J.Modeling the viscoelasto-plastic behavior of waxy crude[J].Petroleum Science,2013,10(3):395-401.
[48]TENG H X,ZHANG J J.Modeling the thixotropic behavior of waxy crude[J].Industrial&Engineering Chemistry Research,2013,52(23):8079-8089.
[49]ZHU C,SMAY J E.Thixotropic rheology of concentrated alumina colloidal gels for solid freeform fabrication[J].Journal of Rheology,2011,55(3):655-672.