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Totally found 6 items.

  • [会议] Phase Behaviour of Solvents/Heavy Oil Systems at High Pressures andElevated Temperatures
    In this paper,techniques have been developed to determine multiphase boundaries of solvent(s)/heavy oilmixtures at high pressures and elevated temperatures in pressure-temperature(P-T),enthalpy-temperature(H-T),and pressure-enthalpy(P-H)phase diagrams,respectively.Theoretically,the Peng-Robinsonequation of state(PR EOS)incorporated with a new alpha function as well as the previously developedenthalpy calculation algorithm are used to predict the multiphase boundaries of the solvent(s)/heavy oilsystems by characterizing the heavy oil as a single pseudocomponent.The PR EOS associated with thenewly developed alpha function is found to be accurate in reproducing the experimentally measured VL1L2(V represents the vapour phase,L1 denotes the high density hydrocarbon-rich liquid phase,and L2 refers tothe low density CO2 liquid phase)three-phase boundary pressures with an overall absolute average relativedeviation(AARD)of 2.01% and maximum average relative deviation(MARD)of 3.54%,respectively.Inaddition,the VL1L2 three-phase boundaries are expanded and tended to move toward the region with highertemperatures and lower pressures in the P-T phase diagram with the addition of either C3H8 or n-C4H_(10)toCO2/heavy oil systems compared to those of only CO2 exists in heavy oil systems.The enthalpy changesrapidly with variation of temperature in both H-T and P-H phase diagrams within the three-phase region.Either two-phase(VL1)or three-phase(VL1L2)isenthalpic flash calculations can be performed straightlyto determine phase fractions and compositions together with system temperature without conducting thestability analysis for a provided solvent(s)/heavy oil mixture at a constant enthalpy and pressure with theconstructed H-T phase diagram.
    关键词: -
  • [会议] Materials,Well Designs and Numerical Simulations for the Construction of aLow Loss Zone for Radiofrequency Downhole Heating
    Downhole RF heating continues to be the interest of the petroleum industry because of its advantages overconventional forms of heating.Previous results have shown that without a low-loss dielectric zone(LLZ)around the downhole RF emitter,none of the available linear dipole antennas can work efficiently,and mostof the energy is absorbed preferentially in a few meter radius around the radiating well and will not penetratesubstantially into the reservoir.To circumvent this problem,low-dielectric materials were proposed,whichare composed of a solid mixed with an appropriate binder.These materials were selected to have lowdielectric properties so that the RF absorption is minimized,and at the same time,low porosity to preventwater invasion during the RF heating operation.Four solids,Ottawa sand,solvent deasphalted tar,Poly(p-phenylene sulfide)(PPS)and Polyether ether ketone(PEEK)and four binders(polydicyclo pentadiene(DCPD)and phenol-formaldehyde resins(Novolac),a C-Class cement slurry,and a foamed cement)wereevaluated by measuring their dielectric properties(dielectric constant and loss tangent)in the frequencyrange 1-2000 kHz and temperatures between 25-200℃.All four solids have low RF absorption as well aslow porosity(<1%),and those values did not change significantly with temperature.Also,smaller dielectricproperties were found for DCPD and Novolac than those found for the cement materials,and the DCPDbinder has a dielectric constant almost half and a loss tangent one order of magnitude lower than thosemeasured for the Novolac resin.Three different designs for the construction of LLZ were considered,whichincluded underreaming the oil well,squeezing a solid-containing binder downhole,and creating a casing-less completion.Numerical simulations show that the use of a low-loss zone around the central emitterleads to a very much improved energy and temperature distribution,and higher penetrations(~12 m)thanthe case without it.
    关键词: -
  • [会议] Measurement of Concentration-Dependent Diffusion Coefficient of GaseousSolvents in Bitumen
    A robust and reliable experimental approach was developed and implemented for measurement of theconcentration-dependent molecular diffusion coefficient of gaseous solvents in bitumen mixtures.Thedeveloped methodology relies on accurate measurement of the rate of gas injection throughout the constant-pressure diffusion experiment.The experimental setup was then used for studying the concentration-dependent behavior of the diffusivity of gaseous dimethyl ether(DME)in bitumen at 2.76 MPa and110℃.The estimated values of the molecular diffusion coefficient are in the range of ~1.79-3.72×10-9m~2/s increasing with the initial concentration of DME in bitumen.The results indicate that there exists anoticeable dependency of the molecular diffusion coefficient on the concentration of the solvent in bitumen.The developed methodology finds application in estimation of the concentration-dependent moleculardiffusion coefficient of gaseous solvents in bitumen.
    关键词: Concentration-dependent diffusion coefficient;Dimethyl ether;Bitumen thermal recovery;Solvent-aided recovery
  • [会议] Materials,Well Designs and Numerical Simulations for the Construction of aLow Loss Zone for Radiofrequency Downhole Heating
    Downhole RF heating continues to be the interest of the petroleum industry because of its advantages overconventional forms of heating.Previous results have shown that without a low-loss dielectric zone(LLZ)around the downhole RF emitter,none of the available linear dipole antennas can work efficiently,and mostof the energy is absorbed preferentially in a few meter radius around the radiating well and will not penetratesubstantially into the reservoir.To circumvent this problem,low-dielectric materials were proposed,whichare composed of a solid mixed with an appropriate binder.These materials were selected to have lowdielectric properties so that the RF absorption is minimized,and at the same time,low porosity to preventwater invasion during the RF heating operation.Four solids,Ottawa sand,solvent deasphalted tar,Poly(p-phenylene sulfide)(PPS)and Polyether ether ketone(PEEK)and four binders(polydicyclo pentadiene(DCPD)and phenol-formaldehyde resins(Novolac),a C-Class cement slurry,and a foamed cement)wereevaluated by measuring their dielectric properties(dielectric constant and loss tangent)in the frequencyrange 1-2000 kHz and temperatures between 25-200℃.All four solids have low RF absorption as well aslow porosity(<1%),and those values did not change significantly with temperature.Also,smaller dielectricproperties were found for DCPD and Novolac than those found for the cement materials,and the DCPDbinder has a dielectric constant almost half and a loss tangent one order of magnitude lower than thosemeasured for the Novolac resin.Three different designs for the construction of LLZ were considered,whichincluded underreaming the oil well,squeezing a solid-containing binder downhole,and creating a casing-less completion.Numerical simulations show that the use of a low-loss zone around the central emitterleads to a very much improved energy and temperature distribution,and higher penetrations(~12 m)thanthe case without it.
    关键词: -
  • [会议] Measurement of Concentration-Dependent Diffusion Coefficient of GaseousSolvents in Bitumen
    A robust and reliable experimental approach was developed and implemented for measurement of theconcentration-dependent molecular diffusion coefficient of gaseous solvents in bitumen mixtures.Thedeveloped methodology relies on accurate measurement of the rate of gas injection throughout the constant-pressure diffusion experiment.The experimental setup was then used for studying the concentration-dependent behavior of the diffusivity of gaseous dimethyl ether(DME)in bitumen at 2.76 MPa and110℃.The estimated values of the molecular diffusion coefficient are in the range of ~1.79-3.72×10-9m~2/s increasing with the initial concentration of DME in bitumen.The results indicate that there exists anoticeable dependency of the molecular diffusion coefficient on the concentration of the solvent in bitumen.The developed methodology finds application in estimation of the concentration-dependent moleculardiffusion coefficient of gaseous solvents in bitumen.
    关键词: Concentration-dependent diffusion coefficient;Dimethyl ether;Bitumen thermal recovery;Solvent-aided recovery
  • [会议] Phase Behaviour of Solvents/Heavy Oil Systems at High Pressures andElevated Temperatures
    In this paper,techniques have been developed to determine multiphase boundaries of solvent(s)/heavy oilmixtures at high pressures and elevated temperatures in pressure-temperature(P-T),enthalpy-temperature(H-T),and pressure-enthalpy(P-H)phase diagrams,respectively.Theoretically,the Peng-Robinsonequation of state(PR EOS)incorporated with a new alpha function as well as the previously developedenthalpy calculation algorithm are used to predict the multiphase boundaries of the solvent(s)/heavy oilsystems by characterizing the heavy oil as a single pseudocomponent.The PR EOS associated with thenewly developed alpha function is found to be accurate in reproducing the experimentally measured VL1L2(V represents the vapour phase,L1 denotes the high density hydrocarbon-rich liquid phase,and L2 refers tothe low density CO2 liquid phase)three-phase boundary pressures with an overall absolute average relativedeviation(AARD)of 2.01% and maximum average relative deviation(MARD)of 3.54%,respectively.Inaddition,the VL1L2 three-phase boundaries are expanded and tended to move toward the region with highertemperatures and lower pressures in the P-T phase diagram with the addition of either C3H8 or n-C4H_(10)toCO2/heavy oil systems compared to those of only CO2 exists in heavy oil systems.The enthalpy changesrapidly with variation of temperature in both H-T and P-H phase diagrams within the three-phase region.Either two-phase(VL1)or three-phase(VL1L2)isenthalpic flash calculations can be performed straightlyto determine phase fractions and compositions together with system temperature without conducting thestability analysis for a provided solvent(s)/heavy oil mixture at a constant enthalpy and pressure with theconstructed H-T phase diagram.
    关键词: -
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