Insight from MRI and Micro-Model Studies of Transport of Solvent into Heavy Oil During Vapex

Fisher, Douglas; Singhal, A.K.; Goldman, Jon; Clive, Jackson; Randall, and

doi:10.2523/79024-ms

Cited by 4 publications

(2 citation statements)

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“…More recently, some state-of-the-art techniques have been applied to estimate the diffusion coefficients of hydrocarbon solvents in heavy oil and bitumen, such as magnetic resonance imaging (MRI), − low field nuclear magnetic resonance (NMR) spectra, and X-ray computer-assisted tomography (CAT) scanning . These techniques require extremely expensive and highly sophisticated apparatuses, which have to be operated by specially trained technicians.…”

Section: Introductionmentioning

confidence: 99%

New Experimental Method for Measuring Gas Diffusivity in Heavy Oil by the Dynamic Pendant Drop Volume Analysis (DPDVA)

Yang

2005

Ind. Eng. Chem. Res.

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This paper presents a new experimental method and its computational scheme for measuring gas diffusivity in heavy oil at high pressures and elevated temperatures by the dynamic pendant drop volume analysis (DPDVA). In the experiment, a see-through windowed high-pressure cell is first filled with a test gas at a prespecified pressure and temperature. Then, a heavy oil sample is introduced by using a syringe pump to form a pendant drop inside the pressure cell. Due to the oil swelling effect, the subsequent dissolution of the gas into the pendant oil drop causes its volume to increase until the saturation state is reached. The sequential digital images of the dynamic pendant oil drop are acquired and analyzed by applying computer-aided image acquisition and processing techniques to measure the oil drop volumes at different times. A mass-transfer model is developed theoretically to describe the diffusion process of the gas into the pendant heavy oil drop. This model is numerically solved by applying the semidiscrete Galerkin finite element method. The volume of the dynamic pendant oil drop is calculated from the numerically predicted transient gas concentration distribution inside the pendant oil drop. The gas diffusivity in heavy oil and the swelling factor of gas-saturated heavy oil are, thus, determined by finding the best fit of the theoretically calculated volumes of the dynamic pendant oil drop to the experimentally measured data. This novel experimental technique is applied to measure CO 2 diffusivities in a heavy oil sample and the swelling factors of a CO 2 -saturated heavy oil at P ) 2, 3, 4, 5, and 6 MPa and T ) 23.9 °C.

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Section: Introductionmentioning

confidence: 99%

New Experimental Method for Measuring Gas Diffusivity in Heavy Oil by the Dynamic Pendant Drop Volume Analysis (DPDVA)

Yang

2005

Ind. Eng. Chem. Res.

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“…Das and Butler and Kok et al analyzed the asphaltene deposition by the VAPEX process in a Hele-Shaw cell, while this work has been studied in a sand-packed cell, with their movement and distribution. Fisher et al conducted the VAPEX studies using magnetic resonance imaging and revealed that, within the solvent−oil mixing regions, asphaltene precipitated and eventually deposited on the solid surfaces , but the behavior of precipitated asphaltene (streaks), such as their movement and distribution, was not investigated.…”

Section: Introductionmentioning

confidence: 99%

Study of Asphaltene and Metal Upgrading in the Vapor Extraction (VAPEX) Process

et al. 2010

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The effect of the vapor dew point and matrix permeability on the movement of deposited streaks in the vapor extraction (VAPEX) process was investigated. Furthermore, the distribution of residual hydrocarbons, asphaltenes, resins, and metal chelate in the VAPEX cell was determined. Finally, the pattern of viscosity distribution in the VAPAX cell was calculated using a Computer Modelling Group (CMG) simulator. The experiments were conducted in sand packed on the Iranian bitumen by propane solvent. Asphaltene, resin, and vanadium chelate were measured in residual hydrocarbon of swept zone via American Society for Testing and Materials (ASTM) D6560 and D1548 test methods. The results demonstrated that in vapor dew point and high permeable matrices, precipitated streaks moved faster than other conditions. Distributions of asphaltene, resin, and vanadium chelate showed a reduction in their facial concentration from the vapor injection port to the oil production port, while the distribution of dissolved vanadium chelate in asphaltene and resin precipitated following a reverse pattern. Moreover, there was a good agreement between the Gillespie equation and experimental data, in which the colloidal volume fraction was divided into volume fractions of asphaltenes, resins, and metal chelates.

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Complex Effect of Connate Water in Vapour Extraction Process

Etminan

2007

SPE Annual Technical Conference and Exhibition

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The objective of this work was to study the effect of connate water in the progression of the Vapor Extraction (VAPEX) process for heavy oil recovery. A large fraction of the physical model tests of the VAPEX process reported in the literature have been conducted without any connate water in the system. The absence of connate water was rationalized by suggesting that it has little or no influence on relative permeability of oil and since the vaporized solvent does not dissolve in water, there is no effect of water on the mass transfer process. We have evaluated the effect of connate water on VAPEX performance using physical model experiments carried out in a visual model, with different connate water saturations. Butane was used as the solvent and fine Ottawa sand was used for packing the model to obtain permeability and capillary pressure values comparable to the field conditions. In addition to the visual observations of the size and shape of the vapor chamber, the rates of oil and gas production were monitored during the experiments. The results show that connate water has a measurable effect on the process, both in terms of the shape of the vapour chamber and the drainage rate of the diluted oil. The presence of connate water causes faster spreading of the vapor chamber in the lateral direction and tends to increase the thickness of the mixing zone. This increase in the mixing zone thickness appears to result from capillarity driven fingering phenomenon. The mixing zone had a distinct uneven appearance that was similar to patterns generated by frontal instabilities in miscible displacements. The effect of connate water on drainage rate was an increase in the initial rate but a reduction in the rate subsequently. The presence of mobile water speeds up the communication between the two wells and leads to even faster spreading of the vapor chamber. Finally, the de-asphalting and oil upgrading was more significant in the presence of connate water. Introduction Vapour Extraction process is a non-thermal energy efficient heavy oil emerging technology which requires lower capital costs and lowers environmental pollution. A simple comparison of this solvent based process with conventional thermal processes shows advantages of this new method of heavy and extra heavy oil production. Solvent based non-thermal heavy oil recovery methods are relatively new and need to be further developed. No field results have been reported from any of the pilot test projects that are currently in process. Although several successful SAGD and CSS field projects have been reported, the high cost of steam generation, considerable energy loss, need for water and water treatment(1) are the problems which necessitate finding a more effective and environmentally friendly recovery method. Meanwhile, Solvent based processes have drawn more attention due to their potential advantages. One of the more attractive solvent based processes is the vapour extraction (VAPEX) process. In this process, vaporized light hydrocarbons, like propane and butane or a mixture of these two with carrier gases, are used. VAPEX is a solvent analogue of the SAGD process and uses essentially the same well configuration (1). Solvent dissolves into the bitumen and drastically reduces its viscosity through dilution, swelling and de-asphalting mechanisms (2). It has been noted that vaporized rather than liquid solvents produce a higher driving force for gravity drainage due to higher density difference between bitumen and solvent (3). The optimum pressure for solvent injection is near its dew point pressure where the solvent solubility in the oil is high. The role of carrier gas is to keep the injected solvent in the vapour phase at the operating pressure. Diluted oil drains along the outer edges of the vapour chamber and the chamber propagates little by little toward the reservoir ends. The primary driving force for the oil drainage is gravity. When the chamber's wings reach to the reservoir ends, the oil production rate starts decreasing due to the reduced gravity head.

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Insight from MRI and Micro-Model Studies of Transport of Solvent into Heavy Oil During Vapex

Cited by 4 publications

References 0 publications

New Experimental Method for Measuring Gas Diffusivity in Heavy Oil by the Dynamic Pendant Drop Volume Analysis (DPDVA)

New Experimental Method for Measuring Gas Diffusivity in Heavy Oil by the Dynamic Pendant Drop Volume Analysis (DPDVA)

Study of Asphaltene and Metal Upgrading in the Vapor Extraction (VAPEX) Process

Complex Effect of Connate Water in Vapour Extraction Process

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