Role of Asphaltene Precipitation in VAPEX Process
- P. Haghighat (University of Calgary) | B.B. Maini (University of Calgary)
- Document ID
- Society of Petroleum Engineers
- Journal of Canadian Petroleum Technology
- Publication Date
- March 2010
- Document Type
- Journal Paper
- 14 - 21
- 2010. Society of Petroleum Engineers
- 4.3.3 Aspaltenes, 2.4.3 Sand/Solids Control, 4.1.2 Separation and Treating, 1.8 Formation Damage, 5.5 Reservoir Simulation, 5.4.6 Thermal Methods, 5.4.7 Chemical Flooding Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex), 5.8.5 Oil Sand, Oil Shale, Bitumen, 5.3.2 Multiphase Flow, 4.3.1 Hydrates, 4.1.9 Heavy Oil Upgrading, 4.1.5 Processing Equipment, 4.6 Natural Gas, 5.3.9 Steam Assisted Gravity Drainage, 5.4.10 Microbial Methods
- asphaltene precipitation, vapour extraction (VAPEX), in situ de-asphalting
- 1 in the last 30 days
- 975 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 35.00|
VAPEX (vapour extraction) is an oil recovery process, in which heavy oil or bitumen is mobilized by injection of a low molecular weight hydrocarbon solvent and is drained by gravity to a horizontal production well. It has attracted considerable attention because of its potential applicability to problematic reservoirs and the potential for in-situ upgrading of heavy oil during the process.
Oil drainage rate under VAPEX is controlled by the viscosity of solvent diluted oil and can be affected substantially by de-asphalting. In-situ de-asphalting can be advantageous because it reduces the oil viscosity and leads to production of upgraded oil. However, the precipitated asphaltenes can also plug the pores of the formation and cause severe damage to the permeability.
The objective of the current work was to determine whether the beneficial effects of asphaltene precipitation would outweigh any formation damage. The effects of in-situ precipitation and deposition of asphaltenes on the rate of oil drainage and the quality of the produced oil under different operating conditions were experimentally evaluated. The experiments were conducted in a physical model, packed with 140 - 200 mesh sand, and propane was used as the solvent. The quality of the produced oil samples was evaluated through the SARA technique and viscosity measurements.
The experimental results show that the oil produced at higher injection pressures was substantially upgraded, but the viscosity reduction by asphaltene precipitation did not lead to higher production rates. The effect of viscosity reduction was negated by the accompanying damage to formation permeability. The huff and puff injection of toluene into the production well, to remove damage from the near well zone, was tried but proved to be ineffective. It led to production of oil with higher asphaltene content with no improvement in the rate of oil production compared to the lower pressure operation without asphaltene precipitation. However, co-injection of toluene with propane was successful in increasing the rate of production and the extent of upgrading obtained was encouraging.
|File Size||1 MB||Number of Pages||7|
1. Upreti, S.R., Lohi, A., Kapadia, R.A., and El-Haj, R. 2007. Vapor Extraction of Heavy Oil andBitumen: A Review. Energy & Fuels 21 (3): 1562-1574.doi:10.1021/ef060341j.
2. Butler, R.M. and Mokrys, I.J. 1989. Solvent Analog Model ofSteam-Assisted Gravity Drainage. AOSTRA Journal of Research 5(1): 17-32.
3. Speight, J.G. 1978. The Structure of Petroleum Asphaltenes: CurrentConcepts, No. 81. Edmonton, Alberta: Information Series, Alberta ResearchCouncil.
4. Firoozabadi, A. 1999. Thermodynamics of Hydrocarbon Reservoirs.New York: McGraw-Hill.
5. Das, S.K. 1998. VAPEX: AnEfficient Process for the Recovery of Heavy Oil and Bitumen. SPE J.3 (3): 232-237. SPE-50941-PA. doi: 10.2118/50941-PA.
6. Nghiem, L.X., Sammon, P.H., and Kohse, B.F. 2001. Modeling Asphaltene Precipitation andDispersive Mixing in the VAPEX Process. Paper SPE 66361 presented at theSPE Reservoir Simulation Symposium, Houston, 11-14 February. doi:10.2118/66361-MS.
7. Mokrys, I.J. and Butler, K.M. 1993. In-Situ Upgrading of Heavy Oils andBitumen by Propane De-Asphalting: The VAPEX Process. Paper SPE 25452presented at the SPE Production Operations Symposium, Oklahoma City, Oklahoma,USA, 21-23 March. doi: 10.2118/25452-MS.
8. Das, S.K. and Butler, R.M. 1998. Mechanism of the Vapour ExtractionProcess for Heavy Oil and Bitumen. J. Pet. Sci. Eng. 21 (1-2):43-59.
9. Talbi, K. and Maini, B.B. 2003. Evaluation of CO2 Based VAPEX Processfor the Recovery of Bitumen from Tar Sand Reservoirs. Paper SPE 84868presented at the SPE International Improved Oil Recovery Conference in AsiaPacific, Kuala Lumpur, 20-21 October. doi: 10.2118/84868-MS.
10. Yazdani, A.J. and Maini, B.B. 2004. New Experimental Model Design forVAPEX Process Experiments. Paper CIPC 2004-263 presented at the CanadianInternational Petroleum Conference, Calgary, 8-10 June. doi:10.2118/2004-263.
11. Yazdani, A.J. and Maini, B.B. 2006. Further Investigation of DrainageHeight Effect on Production Rate in VAPEX. Paper SPE 101684 presented atthe SPE Annual Technical Conference Exhibition, San Antonio, Texas, USA, 24-27September. doi: 10.2118/101684-MS.