A four coefficient model for extending the heptanes-plus fraction for gas condensate systems

Hosein, Raffie; McCain, William D.; Jagai, Tennyson

doi:10.1016/j.petrol.2012.11.007

Cited by 4 publications

(4 citation statements)

References 10 publications

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“…Furthermore, accurate characterization of SCN properties is very important for phase behaviour calculations of fluid samples employing equations of state . This is a known fact for a wide range of reservoir fluids from gas condensates to heavy oils . Detailed experimental composition analysis of plus fractions is rarely available.…”

Section: Introductionmentioning

confidence: 99%

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Optimal distribution function determination for plus fraction splitting

2019

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Reservoir fluid modelling is one of the most important steps in reservoir simulation and modelling of flow lines as well as surface facilities. One of the most uncertain parameters of the reservoir fluids is the plus fraction. An accurate and consistent splitting scheme can reduce this uncertainty and as a result, enhance the modelling of reservoir fluids. The existing schemes for splitting plus fractions are all based on assuming a specific mole fraction-molecular weight distribution with predefined constant values that may yield inaccurate and inconsistent results. In this study, an optimization-based algorithm was developed to determine the aforementioned controlling parameters of the plus fraction distribution function, enforcing the relationship between specific gravity and molecular weight of the single carbon numbers (SCNs). The introduced optimizationbased splitting technique was applied to different samples, covering a wide range of reservoir fluids, including gas condensates, volatile oils, black oils, and heavy oils. The results showed that the proposed technique yielded a more consistent molecular weight-mole fraction distribution concerning the experimental extended analysis of plus fractions, yielding an average relative error of 25.8 % compared to 76, 33.6, and 45.9 % for the Katz, Ahmed, and Whitson methods, respectively. It was also shown that the proposed method results in more accurate and more consistent phase behaviour predictions than the existing methods concerning the experimental data. Furthermore, the results showed that the introduced optimization-based method yields monotonic split samples regarding specific gravity and molecular weight, while the conventional techniques do not guarantee to preserve the monotonicity.

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Section: Introductionmentioning

confidence: 99%

“…Detailed experimental composition analysis of plus fractions is rarely available. Therefore, mathematical methods, known as splitting schemes, are developed for their characterization …”

Section: Introductionmentioning

confidence: 99%

Optimal distribution function determination for plus fraction splitting

2019

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“…However, the generalized discrete distribution format proposed is only an approximation of the real distribution curve. Other recent works have only evaluated the boiling point distribution of oils using various distribution functions, such as the Kumaraswamy and Weibull extreme functions. , Furthermore, Hosein and colleagues proposed a splitting technique to model the molecular weight distribution in gas condensates.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Bubble Pressure for Crude Oils: The Effect of q-Weibull Distribution for Splitting the Heavy Fraction

et al. 2019

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Thermodynamic calculations involving crude oils require a proper characterization of the heavy-fraction in order to describe the phase behavior. Bubble pressure is a key property, and its calculation depends on splitting the heavyfraction of the crude oil through a distribution function to obtain properties such as molecular weight and specific gravity. Small changes in these properties can significantly affect phase behavior calculations. The exponential and gamma distributions are the most used for splitting but they fail in characterizing many oils. Alternatively, the q-Weibull distribution is proposed to the splitting step instead of the exponential and gamma distributions in order to calculate the molecular weight and specific gravity. These three distributions are critically tested and compared for 13 oils with extended composition selected from the literature, stressing the effect of the characterization methods on the calculation of bubble pressure for reservoir fluids.

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“…Different characterization approaches and combination of mentioned steps are proposed for reservoir fluids. There are many different techniques proposed for splitting (Lohrenz et al 1964;Ahmed et al 1985;Ahmed 1989;Pedersen and Christensen 2007;Hosein and McCain 2012) among which splitting plus fraction into pseudo-components using semicontinuous thermodynamics as proposed by Behrens and Sandler and completed by Whitson and Brulé has attracted more attention (Ezekwe 2011). In this method, three-parameter gamma probability function is utilized to describe molar distribution (Whitson and Brulé 2000).Whitson investigated that light fluids such as gas condensate and volatile oil usually have exponential distribution while some heavier ones follow gamma distribution (Ahmed 1989).…”

Section: Introductionmentioning

confidence: 99%

Impact of fluid characterization on compositional gradient in a volatile oil reservoir

Kiani

Osfouri

Azin

et al. 2015

J Petrol Explor Prod Technol

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Compositional gradient known as a potential of vertically variations in composition (and sometimes areal changes) has a remarkable effect on reservoir management steps such as estimation of initial hydrocarbon in place, design of downstream equipments and prediction of gas-oil contact. One of the main steps in development of compositional grading is to characterize fluid sample. In this study, compositional grading is studied in a volatile oil sample from an oil field in south of Iran. Implemented models are based on isothermal and non-isothermal, i.e., zero diffusion, Hasse and Kempers models. Results illustrated that isothermal and zero diffusion models are in appropriate consistency with field data. Then, effect of C 10? splitting on compositional grading was studied. It was shown that splitting of C 10? to more pseudo-components does not have significant effect on variation in composition of hydrocarbon and non-hydrocarbon components.

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A four coefficient model for extending the heptanes-plus fraction for gas condensate systems

Cited by 4 publications

References 10 publications

Optimal distribution function determination for plus fraction splitting

Optimal distribution function determination for plus fraction splitting

Calculation of Bubble Pressure for Crude Oils: The Effect of q-Weibull Distribution for Splitting the Heavy Fraction

Impact of fluid characterization on compositional gradient in a volatile oil reservoir

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