Effect of GOR on Gas Diffusivity in Reservoir-Fluid Systems
- Ram R. Ratnakar (Shell International Exploration and Production) | Birol Dindoruk (Shell International Exploration and Production)
- Document ID
- Society of Petroleum Engineers
- SPE Journal
- Publication Date
- February 2020
- Document Type
- Journal Paper
- 185 - 196
- 2020.Society of Petroleum Engineers
- Henry's constant, pressure-decay test, late transient solution, diffusivity, gas-to-oil ratio
- 3 in the last 30 days
- 100 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 35.00|
Molecular diffusion plays a dominant role in various reservoir processes, especially in the absence of convective mixing. In general, gas diffusion in oils depends on several factors such as pressure, temperature, oil viscosity, and gas/oil ratio (GOR). Out of these factors, the effects of GOR and live-oil-compositional changes on diffusivity are rare or not available in the literature. The current work fills this gap and presents the experimental observations on the effect of GOR on gas diffusivity in reservoir-fluid systems.
Synthetic live oils were created by combining stock-tank oil (STO) and methane in various ratios. Constant-composition-expansion (CCE) experiments were performed with these oils to obtain their bubblepoints and liquid densities in relation to GOR. Methane diffusivity in these oils was obtained from pressure-decay (PD) tests at high-pressure/high-temperature (HP/HT) conditions. The diffusion and solubility parameters were estimated from PD data using the diffusion model and integral-based linear regression presented in previous work (Ratnakar and Dindoruk 2015, 2018). The experimental and modeling methodologies are presented here in sufficient detail to allow readers to replicate and evaluate the results.
In this work, we experimentally investigated the effect of GOR on methane diffusivity in oils at HP/HT conditions using PD tests. In particular,
- We present experimental data for bubblepoints and liquid density of synthetic oils with various GOR values. For the range of GORs considered, these measurements show that the bubblepoint pressure increases linearly with GOR.
- Late-transient solution (LTS) of the PD model was used to obtain diffusivity parameters by regressing against experimental data. It is found that as the GOR value increases (that is, when oil becomes lighter), the diffusivity value increases, which is in accordance with the Stokes-Einstein relation.
- Most importantly, an empirical correlation is developed on the basis of a limited data set to describe the variation in diffusivity values with GOR. This can be important when experimental data are available for the STO but not for the live oils. It can also be extremely useful in gas-injection processes where the amount of gas dissolved in the oil varies, leading to variations in diffusivity.
|File Size||1 MB||Number of Pages||12|
Bosse, D. and Bart, H.-J. 2006. Prediction of Diffusion Coefficients in Liquid Systems. Ind Eng Chem Res 45: 1822–1828. https://doi.org/10.1021/ie0487989.
Boustani, A. and Maini, B. B. 2001. The Role of Diffusion and Convective Dispersion in Vapor Extraction Process. J Can Pet Technol 40 (4): 68–77. PETSOC-01-04-05. https://doi.org/10.2118/01-04-05.
Campbell, B. T. and Orr, F. M. 1985. Flow Visualization of CO2-Crude Oil Mixtures. Society of Petroleum Engineers Journal 25 (5): 665–678. SPE-11958-PA. https://doi.org/10.2118/11958-PA.
Civan, F. and Rasmussen, M. L. 2001. Accurate Measurement of Gas Diffusivity in Oil and Brine Under Reservoir Conditions. Presented at the SPE Production and Operations Symposium, Oklahoma City, Oklahoma, 24–27 March. SPE-67319-MS. https://doi.org/10.2118/67319-MS.
Civan, F. and Rasmussen, M. L. 2002. Improved Measurement of Gas Diffusivity for Miscible Gas Flooding Under Non-Equilibrium Versus Equilibrium Conditions. Presented at the SPE/DOE Improved Oil Recovery Symposium, Tulsa, Oklahoma, 13–17 April. SPE-75135-MS. https://doi.org/10.2118/75135-MS.
Civan, F. and Rasmussen, M. L. 2003. Analysis and Interpretation of Gas Diffusion in Quiescent Reservoir, Drilling and Completion Fluids: Equilibrium Versus Non-Equilibrium Models. Presented at the SPE Annual Technical Conference and Exhibition, Denver, Colorado, 5–8 October. SPE-84072-MS. https://doi.org/10.2118/84072-MS.
Creux, P., Meyer, V., Cordelier, P. R. et al. 2005. Diffusivity in Heavy Oils. Presented at the SPE International Thermal Operations and Heavy Oil Symposium, Calgary, Alberta, Canada, 1–3 November. SPE-97798-MS. https://doi.org/10.2118/97798-MS.
Dill, K. A. and Bromberg, S. 2003. Molecular Driving Forces: Statistical Thermodynamics in Chemistry and Biology. New York, New York: Garland Science, Taylor & Francis Group, LLC.
Dindoruk, B. and Christman, P. G. 2004. PVT Properties and Viscosity Correlations for Gulf of Mexico Oils. SPE Res Eval & Eng 7 (6): 427–437. SPE-89030-PA. https://doi.org/10.2118/89030-PA.
Etminan, S. R., Maini, B. B., Hassanzadeh, H. et al. 2009. Determination of Concentration Dependent Diffusivity Coefficient in Solvent Gas Heavy Oil Systems. Presented at the SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, 4–7 October. SPE-124832-MS. https://doi.org/10.2118/124832-MS.
Grogan, A. T. and Pinczewski, W. V. 1987. The Role of Molecular Diffusion Processes in Tertiary CO2 Flooding. J Pet Technol 39 (5): 591–602. SPE-12706-PA. https://doi.org/10.2118/12706-PA.
Hayduk, W. and Minhas, B. S. 1982. Correlations for Predictions of Molecular Diffusivities in Liquids. Can J Chem Eng 60 (2): 295–299. https://doi.org/10.1002/cjce.5450600213.
Huang, E. T. S. and Tracht, J. H. 1974. The Displacement of Residual Oil by Carbon Dioxide. Presented at the SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, 22–24 April. SPE-4735-MS. https://doi.org/10.2118/4735-MS.
Jamialahmadi, M., Emadi, M., and Mu¨ller-Steinhagen, H. 2006. Diffusion Coefficients of Methane in Liquid Hydrocarbons at High Pressure and Temperature. J Pet Sci Eng 53 (1–2): 47–60. https://doi.org/10.1016/j.petrol.2006.01.011.
Li, X. and Yortsos, Y. C. 1995. Theory of Multiple Bubble Growth in Porous Media by Solute Diffusion. Chem Eng Sci 50 (8): 1247–1271. https://doi.org/10.1016/0009-2509(95)98839-7.
Moganty, S. S. and Baltus, R. E. 2010. Diffusivity of Carbon Dioxide in Room-Temperature Ionic Liquids. Ind Eng Chem Res 49 (19): 9370–9376. https://doi.org/10.1021/ie101260j.
Pedersen, K. S., Christensen, P. L., Shaikh, J. A. et al. 2006. Phase Behavior of Petroleum Reservoir Fluids. Boca Raton, Florida: CRC Press.
Petrosky, G. E., Jr. and Farshad, F. F. 1993. Pressure–Volume–Temperature Correlations for Gulf of Mexico Crude Oils. Presented at the SPE Annual Technical Conference and Exhibition, Houston, Texas, 3–6 October. SPE-26644-MS. https://doi.org/10.2118/26644-MS.
Ratnakar, R. R. and Balakotaiah, V. 2014. Coarse-Graining of Diffusion–Reaction Models With Catalyst Archipelagos. Chem Eng Sci 110: 44–54. https://doi.org/10.1016/j.ces.2013.08.011.
Ratnakar, R. R. and Dindoruk, B. 2015. Measurement of Gas Diffusivity in Heavy Oils and Bitumens by Use of Pressure-Decay Test and Establishment of Minimum Time Criteria for Experiments. SPE J. 20 (5): 1167–1180. SPE-170931-PA. https://doi.org/10.2118/170931-PA.
Ratnakar, R. R. and Dindoruk, B. 2018. Analysis and Interpretation of Pressure-Decay Tests for Gas/Bitumen and Oil/Bitumen Systems: Methodology Development and Application of New Linearized and Robust Parameter-Estimation Technique Using Laboratory Data. SPE J. 24 (3): 951–972. SPE-181514-PA. https://doi.org/10.2118/181514-PA.
Ratnakar, R. R., Kalia, N., and Balakotaiah, V. 2012. Carbonate Matrix Acidizing With Gelled Acids: An Experiment-Based Modeling Study. Presented at the SPE International Production and Operations Conference and Exhibition, Doha, Qatar, 14–16 May. SPE-154936-MS. https://doi.org/10.2118/154936-MS.
Ratnakar, R. R., Kalia, N., and Balakotaiah, V. 2013. Modeling, Analysis and Simulation of Wormhole Formation in Carbonate Rocks With In Situ Cross-Linked Acids. Chem Eng Sci 90: 179–199. https://doi.org/10.1016/j.ces.2012.12.019.
Ratnakar, R. R., Lewis, E. J., and Dindoruk, B. 2018. Effect of Dilution on Acoustic and Transport Properties of Reservoir Fluid Systems. Presented at the SPE EOR Conference at Oil and Gas West Asia, Muscat, Oman, 26–28 March, SPE-190480-MS. https://doi.org/10.2118/190480-MS.
Renner, T. A. 1988. Measurement and Correlation of Diffusion Coefficients for CO2 and Rich-Gas Applications. SPE Res Eng 3 (2): 517–523. SPE-15391-PA. https://doi.org/10.2118/15391-PA.
Riazi, M. R. 1996. A New Method for Experimental Measurement of Diffusion Coefficients in Reservoir Fluids. J Pet Sci Eng 14 (3–4): 235–250. https://doi.org/10.1016/0920-4105(95)00035-6.
Riazi, M. R. and Whitson, C. H. 1993. Estimating Diffusion Coefficients of Dense Fluids. Ind. Eng. Chem. Res. 32 (12): 3081–3088. https://doi.org/10.1021/ie00024a018.
Sachs, W. 1998. The Diffusional Transport Methane in Liquid Water: Method and Result of Experimental Investigation at Elevated Pressure. J Pet Sci Eng 21 (3–4): 53–164. https://doi.org/10.1016/S0920-4105(98)00048-5.
Sheikha, H., Pooladi-Darvish, M., and Mehrotra, A. K. 2005. Development of Graphical Methods for Estimating the Diffusivity Coefficient of Gases in Bitumen From Pressure-Decay Data. Energy Fuels 19 (5): 2041–2049. https://doi.org/10.1021/ef050057c.
Shelton, J. L. and Schneider, F. N. 1975. The Effects of Water Injection on Miscible Flooding Methods Using Hydrocarbons and Carbon Dioxide. SPE J. 15 (3): 217–226. SPE-4580-PA. https://doi.org/10.2118/4580-PA.
Sigmund, P. M. 1976. Prediction of Molecular Diffusion at Reservoir Conditions. Part I—Measurements and Predictions of Binary Dense Gas Diffusion Coefficients. J Can Pet Technol 15 (2): 48–57. PETSOC-76-02-05. https://doi.org/10.2118/76-02-05.
Song, L., Kantzas, A., and Bryan, J. L. 2010. Investigation of CO2 Diffusivity in Heavy Oil Using X-Ray Computer-Assisted Tomography Under Reservoir Conditions. Presented at the SPE International Conference on CO2 Capture, Storage, and Utilization. New Orleans, Louisiana, 10–12 November. SPE-138205-MS. https://doi.org/10.2118/138205-MS.
Stalkup, F. J. 1970. Displacement of Oil by Solvent at High Water Saturation. Society of Petroleum Engineers Journal 10 (4): 337–348. SPE-2419-PA. https://doi.org/10.2118/2419-PA.
Standing, M. B. 1977. Volumetric and Phase Behavior of Oil Field Hydrocarbon Systems, p. 130. Dallas, Texas: Society of Petroleum Engineers.
Vignes, A. 1966. Diffusion in Binary Solutions. Variation of Different Coefficient with Composition. Ind. Eng. Chem. Fund. 5 (2): 189–199. https://doi.org/10.1021/i160018a007.
Wen, Y. W. and Kantzas, A. 2005. Monitoring Bitumen-Solvent Interactions With Low-Field Nuclear Magnetic Resonance and X-Ray Computer-Assisted Tomography. Energy Fuels 19 (4): 1319–1326. https://doi.org/10.1021/ef049764g.
Yang, C. and Gu, Y. 2006. Diffusion Coefficients and Oil Swelling Factor of Carbon Dioxide, Methane, Ethane, Propane, and Their Mixtures in Heavy Oil. Fluid Phase Equilib 243 (1–2): 64–73. https://doi.org/10.1016/j.fluid.2006.02.020.
Yanze, Y. and Clemens, T. 2012. The Role of Diffusion for Nonequilibrium Gas Injection Into a Fractured Reservoir. SPE Res Eval & Eng 15 (1): 60–71. SPE-142724-PA. https://doi.org/10.2118/142724-PA.
Zamanian, E., Hemmati, M., and Beiranvand, M. S. 2012. Determination of Gas-Diffusion and Interface-Mass-Transfer Coefficients in Fracture-Heavy Oil Saturated Porous Matrix System. Nafta Sci J 63 (11–12): 351–358.
Zhang, Y. P., Hyndman, C. L., and Maini, B. B. 2000. Measurement of Gas Diffusivity in Heavy Oils. J Pet Sci Eng 25 (1–2): 37–47. https://doi.org/10.1016/S0920-4105(99)00031-5.
Zheng, S. and Yang, D. 2017. Determination of Individual Diffusion Coefficients of C3H8/n-C4H10/CO2/Heavy-Oil Systems at High Pressures and Elevated Temperatures by Dynamic Volume Analysis. SPE J. 22 (3): 799–816. SPE-179618-PA. https://doi.org/10.2118/179618-PA.
Zheng, S., Li, H. A., Sun, H. et al. 2016. Determination of Diffusion Coefficient for Alkane Solvent–CO2 Mixtures in Heavy Oil With Consideration of Swelling Effect. Ind. Eng. Chem. Res. 55 (6): 1533–1549. https://doi.org/10.1021/acs.iecr.5b03929.