Lumped-Component Characterization of Crude Oils for Compositional Simulation

Techniques have been developed to experimentally and theoretically determine phase behaviour and viscosity reduction of CO 2 -heavy oil systems at high pressures and elevated temperatures. Experimentally, vapour-liquid phase boundaries (i.e., saturation pressure lines) and the swelling factors are measured by conducting PVT tests at pressures up to 11094.0 kPa and temperatures up to 362.75 K, respectively. The viscosity of CO 2 -saturated heavy oil is measured at 319.15 K. Theoretically, the heavy oil sample is respectively characterized as a single-and multi-pseudocomponent(s). An exponential distribution function is used to split the plus fraction of heavy oil up to C 105ϩ , while a logarithm-type lumping method is used to group the single carbon numbers (SCNs) into multiple pseudocomponents. Then, the Peng-Robinson equation of state (PR EOS) coupled with the modified alpha function is applied to quantify the phase and volumetric behaviour of the CO 2 -heavy oil systems. The binary interaction parameters (BIPs) for CO 2 -pseudocomponent(s) pair are tuned to match the measured saturation pressures. Compared with the characterization scheme of treating heavy oil as a single pseudocomponent, the absolute average relative deviation (AARD) for the predicted saturation pressures can be improved from 5.27% to 4.56% by characterizing the heavy oil as six pseudocomponents. With the optimum BIPs, the swelling factors are predicted by the PR EOS with and without the volume translation technique, respectively. It is found that the introduction of the volume shift to each (pseudo)component in the PR EOS is able to provide more accurate prediction in both characterization schemes with AARD of 1.88% (oil as a single pseudocomponent) and 1.39% (oil as six pseudocomponents), respectively.

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“…Therefore, the SCNs are lumped into six pseudocomponents by using the following mixing rule (Hong, 1982),…”

Section: Scn Propertiesmentioning

confidence: 99%

Phase Behaviour and Viscosity Reduction of CO2-Heavy Oil Systems at High Pressures and Elevated Temperatures

Yang

Fan

2014

Day 1 Tue, June 10, 2014

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“…40 % and 60 %). When they showed very good comparison as shown in the figure 8 for the case of Crude A and 20 % carbon dioxide, the simulator was used for all the other proportions of carbon dioxide to produce a pressure-composition diagram similar to Hong's typical diagram (Hong, 1982).…”

Section: Crude Oil Swelling In Presence Of Comentioning

confidence: 99%

Phase Behavior Aspects of Carbon Dioxide (CO2) Miscible Flooding in Tight Cores: A Case Study

et al. 2010

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Carbon dioxide flooding process has been a proven valuable tertiary enhanced oil recovery technique. Although the petroleum industry has been applying the technique to produce heavy oil, it can be an effective tool to yield appreciable recoveries from complicated formations to produce comparatively lighter oil. The focus of experimental studies has been on the production of heavy oil and Carbon dioxide application to a wide range of other geological conditions and for wide range of petroleum fluids has been a less traversed path. Especially the process can be applied to tight formations where normal production procedures are not economically viable. This unviability may be due to rock or rock-fluid interactive properties. A research program for evaluation of the feasibility of development of such tight formations in the Middle East has been initiated. The research work included determination of minimum miscibility pressure (MMP), CO2 Core flooding and phase behavior investigation. Since both these processes are governed by the phase behavior; an investigation of phase behavior and PVT properties of reservoir fluids when combined with carbon dioxide are an integral part for a complete evaluation of crude oil extraction process. This paper presents the experimental and simulated phase behavior data for various mixtures of a live crude oil and carbon dioxide. The data helped in designing of the slim tube investigations and core flooding experiments. The phase behavior during a CO2 flooding is a very complex process. Three mechanisms; oil swelling, reduction of oil viscosity, and the acidization of carbonate help obtaining better recovery in a CO2 flooding process. First two are the mechanisms boosting the miscibility between CO2 and reservoir oil. The other parameters which effect phase behavior during a CO2 flooding are the temperature, pressure and rock-fluid interactive properties of the reservoir. Carbon dioxide can be first contact miscible with crude oils, but usually at very high pressure. Attaining and operating a flooding process at these pressures is not financially desirable. Multi contact miscible process is preferred as the economical process for the carbon dioxide flooding. The phase behavior of the original oil and after addition of different amounts of CO2 was studied by performing Constant Composition Expansion (CCE) tests. The bubble point pressure determined for the original oil sample and with increasing carbon dioxide. The phase behavior properties like bubble point pressure amount of liquid for the mixture with carbon dioxide range matched well with Equation of State (EOS) simulations. A comparison of the average density of the crude oil CO2 mixtures confirmed the swelling process. A material balance study between the injected and produced material from the core was also done for verification.

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“…Hong (1982) used the weight fraction average, , for the mixing parameter in characterizing the fractions. Hong (1982) used the weight fraction average, , for the mixing parameter in characterizing the fractions.…”

Section: Lee's Lumping Schemementioning

confidence: 99%

An Approach for Characterization and Lumping of Plus Fractions of Heavy Oil

Rodriguez

Hamouda

2008

International Thermal Operations and Heavy Oil Symposium

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Heavy Oil fluids contain large concentrations of high molecular weight components, hence large content of the plus fractions, such as . Different approaches have been developed to characterize the petroleum plus fractions to improve prediction of the pseudo-components properties by equations of state (EOS).A method is developed, in this work, to split the plus fraction into single carbon numbers (SCN); generating the mole fraction and the respective molecular weight. The developed method is based on the relationships between three parameter gamma distribution (TPG), experimental mole fraction, molecular weight and single carbon number data obtained from literature and industrial contacts. TPG is used to fit the trend of the compositional analysis. The characterized mole distribution as function of single carbon number is generated by integrating the TPG between the limiting molecular weights (). The limiting molecular weights are determined simultaneously during the integration process by fitting the characterized and experimental mole fractions.The developed method is easy to use. In addition the approach is not dependent on fixed molecular weights assumption that only normal carbon numbers exist in the composition.There are several correlations generated to predict physico-chemical properties as a function of SCN. Those correlations have been originally developed to work with light oil. The developed approach together along with some of the correlations is tested for heavy oil samples to identify the ranges where they can be applied. Two lumping schemes are used to group the single carbon numbers into pseudo-components. The properties for each pseudo-component, in this work, are used to predict PVT data, constant volume depletion, using Peng-Robinson equation of state, PVTP commercial simulator.

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Lumped-Component Characterization of Crude Oils for Compositional Simulation

Cited by 50 publications

References 1 publication

Phase Behaviour and Viscosity Reduction of CO2-Heavy Oil Systems at High Pressures and Elevated Temperatures

Phase Behaviour and Viscosity Reduction of CO2-Heavy Oil Systems at High Pressures and Elevated Temperatures

Phase Behavior Aspects of Carbon Dioxide (CO2) Miscible Flooding in Tight Cores: A Case Study

An Approach for Characterization and Lumping of Plus Fractions of Heavy Oil

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