Effect of Oil Saturation on the Flow of Emulsified Acids in Carbonate Rocks
- Mohammed A. Sayed (Aramco Services Company) | Ahmed I. Assem (Texas A&M University) | Hisham A. Nasr-El-Din (Texas A&M University)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- February 2014
- Document Type
- Journal Paper
- 29 - 41
- 2014.Society of Petroleum Engineers
- 3.2.4 Acidising, 4.1.2 Separation and Treating, 5.2.1 Phase Behavior and PVT Measurements, 5.8.7 Carbonate Reservoir
- wormholes, emulsified acid, acidizing, acid propagation, droplet size
- 0 in the last 30 days
- 497 since 2007
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Matrix acid treatments in carbonate reservoirs target stimulation of the near-well region. Emulsified acid can be used in matrix acidizing and acid-fracturing treatments. The delayed nature of emulsified acid is useful in creating deep wormholes and etched fracture surfaces. Almost all previous coreflood work was performed on cores fully saturated with water. Therefore, the main objective of the present work is to study the effect of oil saturation in the formation on the flow of emulsified acids in carbonate cores and assess the performance of emulsified acid in stimulating carbonate formations. A coreflood study was conducted using Indiana limestone cores that were 1.5 in. in diameter and 6 in. in length. The effect of the presence of crude oil on the volume of acid to breakthrough was studied. Also, the size, number, and distribution of the wormholes were determined with computed-tomography (CT) images. The effect of the acid injection rate on the performance of emulsified acid was investigated. Cores that were fully saturated with water, fully saturated with crude oil, and saturated with crude oil at irreducible water saturation were used. There was no optimum injection rate for emulsified acids when they were injected into Indiana limestone cores with permeabilities of 47 to 238 md. In such a range of permeability, emulsified acid enhanced the rock permeability when the acid was injected at both high (10.0 cm3/min) and low (0.5 cm3/min) rates. For cores fully saturated with crude oil, the volume of emulsified acid to achieve breakthrough was 2.2 times more than that required to achieve breakthrough in cores fully saturated with water. The increase in emulsified-acid volume refers to the increase in the volume of the continuous phase resulting from the mixture of the crude oil and diesel and the subsequent change in the acid/diesel volume fraction. As a result, more acid was consumed to create wormholes and achieve the breakthrough. The emulsified-acid system was effective in stimulating limestone cores, whether these cores were saturated with water, oil, or oil at irreducible water saturation.
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Al-Anazi, H.A., Nasr-El-Din, H.A., and Mohamed, S.K. 1998. Stimulation of Tight Carbonate Reservoirs Using Acid-in-Diesel Emulsions: Field Application. Presented at the SPE Formation Damage Control Conference, Lafayette, Louisiana, USA, 18–19 February. SPE-39418-MS. http://dx.doi.org/10.2118/39418-MS.
Al-Harbi, M.S., Al-Dhafeeri, A.M., Al-Rufaie, Y.A. et al. 2006. Evaluation of Acid Treatment Results for Water-Injection Wells in Saudi Arabia. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 24-27 September. SPE-101344-MS. http://dx.doi.org/10.2118/101344-MS.
Al-Mutairi, S.H., Al-Obied, M.A., Al-Yami, I. et al. 2012. Wormhole Propagation in Tar During Matrix Acidizing of Carbonate Formations. Presented at the SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 15-17 February. SPE-151560-MS. http://dx.doi.org/10.2118/151560-MS.
Al-Mutairi, S.H., Hill, A.D., and Nasr-El-Din, H.A. 2008. Effect of Droplet Size, Emulsifier Concentration, and Acid-Volume Fraction on the Rheological Properties and Stability of Emulsified Acids. SPE Prod & Oper 23 (4): 484-497. SPE-107741-PA. http://dx.doi.org/10.2118/107741-PA.
Al-Mutairi, S.H., Nasr-El-Din, H.A., and Hill, A.D. 2009. Droplet Size Analysis of Emulsified Acid. Presented at the SPE Saudi Arabia Section Technical Symposium, AlKhobar, Saudi Arabia, 9-11 May. SPE-126155-MS. http://dx.doi.org/10.2118/126155-MS.
Appicciutoli, D., Maier, R.W., Strippoli, P. et al. 2010. Novel Emulsified Acid Boosts Production in a Major Carbonate Oil Field with Asphaltene Problems. Presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19-22 September. SPE-135076-MS. http://dx.doi.org/10.2118/135076-MS.
Bazin, B. and Abdulahad, G. 1999. Experimental Investigation of Some Properties of Emulsified Acid Systems for Stimulation of Carbonate Formations. Presented at the Middle East Oil Show and Conference, Bahrain, 20-23 February. SPE-53237-MS. http://dx.doi.org/10.2118/53237-MS.
Buijse, M.A. and van Domelen, M.S. 2000. Novel Application of Emulsified Acids to Matrix Stimulation of Heterogeneous Formations. SPE Prod & Oper 15 (3): 208-213. SPE-65355-PA. http://dx.doi.org/10.2118/65355-PA.
de Groote, M. 1933. Process for Increasing the Output of Oil Wells. US Patent No. 1,922,154.
Einstein, A. 1906. Eine neue Bestimmung der Moleküldimensionen (A new determination of the molecular dimensions). Ann. Phys. 19 (2): 289–306.
Fattah, W.A. and Nasr-El-Din, H.A. 2010. Acid Emulsified in Xylene: A Cost-Effective Treatment To Remove Asphalting Deposition and Enhance Well Productivity. SPE Prod & Oper 25 (2): 151-154. SPE-117251-PA. http://dx.doi.org/10.2118/117251-PA.
Gomaa, A.M., Wang, G., and Nasr-El-Din, H.A. 2011. An Experimental Study of a New VES Acid System: Considering the Impact of CO2 Solubility. Presented at the SPE International Symposium on Oilfield Chemistry, The Woodlands, Texas, USA, 11-13 April. SPE-141298-MS. http://dx.doi.org/10.2118/141298-MS.
Hoefner, M.L. and Fogler, H.S. 1985. Effective matrix acidizing in carbonates using microemulsions. Chem. Eng. Prog. 81 (5): 40-44. OSTI ID: 6405788.
Hoefner, M.L., Fogler, H.S., Stenius, P. et al. 1987. Role of Acid Diffusion in Matrix Acidizing of Carbonates. J Pet Technol 39 (2): 203–208. SPE-13564-PA. http://dx.doi.org/10.2118/13564-PA.
Kasza, P., Dziadkiewicz, M., and Czupski, M. 2006. From Laboratory Research to Successful Practice: A Case Study of Carbonate Formation Emulsified Acid Treatments. Presented at the International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana USA, 15-17 February. SPE-98261-MS. http://dx.doi.org/10.2118/98261-MS.
Lynn, J.D. and Nasr-El-Din, H.A. 1999. Formation Damage Associated with Water-Based Drilling Fluids and Emulsified Acid Study. Presented at the SPE European Formation Damage Conference, The Hague, Netherlands, 31 May-1 June. SPE-54718-MS. http://dx.doi.org/10.2118/54718-MS.
Maples, R.E. 2000. Petroleum Refinery Process Economics, second edition. Tulsa, Oklahoma: Penn Well Books.
Metrohm USA. 2010. Metrohm 907 Titrando, http://www.metrohmusa.com/Products/Titration/Potentiometric/Titrando/907-Titrando/index.html (accessed 2013).
Mohamed, S.K., Nasr-El-Din, H.A., and Al-Furaidan, Y.A. 1999. Acid Stimulation of Power Water Injectors and Saltwater Disposal Wells in a Carbonate Reservoir in Saudi Arabia: Laboratory Testing and Field Results. Presented at the SPE Annual Technical Conference and Exhibition, Houston, 3-6 October. SPE-56533-MS. http://dx.doi.org/10.2118/56533-MS.
Nasr-El-Din, H.A., Al-Anazi, H.A., and Mohamed, S.K. 2000. Stimulation of Water-Disposal Wells Using Acid-in-Diesel Emulsions: Case Histories. SPE Prod & Oper 15 (3): 176-182. SPE-65069-PA. http://dx.doi.org/10.2118/65069-PA.
Nasr-El-Din, H.A., Al-Driweesh, S., Al-Muntasheri, G.A. et al. 2003. Acid Fracturing HT/HP Gas Wells Using a Novel Surfactant Based Fluid System. Presented at the SPE Annual Technical Conference and Exhibition, Denver, 5-8 October. SPE-84516-MS. http://dx.doi.org/10.2118/84516-MS.
Otsubo, Y. and Prud'homme, R.K. 1994. Rheology of oil-in-water emulsions. Rheol. Acta 33 (1): 29-37. http://dx.doi.org/10.1007/bf00453461.
Saneifar, M., Nasr-El-Din, H.A., Nasralla, R.A. et al. 2011. Effect of Spent Acids on the Wettability of Sandstones and Carbonates at High Temperature and Pressure. Presented at the SPE European Formation Damage Conference, Noordwijk, The Netherlands, 7-10 June. SPE-144132-MS. http://dx.doi.org/10.2118/144132-MS.
Sayed, M. and Nasr-El-Din, H. 2013. Acid Treatments in High Temperature Dolomitic Carbonate Reservoirs Using Emulsified Acids: A Coreflood Study. Presented at the 2013 SPE Production and Operations Symposium, Oklahoma City, Oklahoma, USA, 23−26 March. SPE-164487-MS. http://dx.doi.org/10.2118/164487-MS.
Sayed, M., Nasr-El-Din, H.A., and Nasrabadi, H. 2013. Reaction of Emulsified Acids With Dolomite. J Can Pet Technol 52 (3): 164-175. SPE-151815-PA. http://dx.doi.org/10.2118/151815-PA.
Sayed, M.A. and Nasr-El-Din, H.A. 2011a. Elastic Properties of Emulsified Acids: Effect of Emulsifier Concentration and Temperature. Presented at the SPE/DGS Saudi Arabia Section Technical Symposium and Exhibition, Al-Khobar, Saudi Arabia, 15-18 May. SPE-149074-MS. http://dx.doi.org/10.2118/149074-MS.
Sayed, M.A.I. and Nasr-El-Din, H. 2011b. Effect of Emulsifier Concentration and Acid Volume Fraction on the Elastic Properties of Emulsified Acids. Presented at the SPE Middle East Oil and Gas Show and Conference, Manama, Bahrain, 25-28 September. SPE-141664-MS. http://dx.doi.org/10.2118/141664-MS.
Sayed, M.A.I., Nasr-El-Din, H.A., Zhang, L. et al. 2012. A New Emulsified Acid to Stimulate Deep Wells In Carbonate Reservoirs: Coreflood and Acid Reaction Studies. Presented at the North Africa Technical Conference and Exhibition, Cairo, Egypt, 20-22 February. SPE-151062-MS. http://dx.doi.org/10.2118/151062-MS.
Shukla, S., Zhu, D., and Hill, A.D. 2006. The Effect of Phase Saturation Conditions on Wormhole Propagation in Carbonate Acidizing. SPE J. 11 (3): 273-281. SPE-82273-PA. http://dx.doi.org/10.2118/82273-PA.
Woelflin, W. 1942. The Viscosity of Crude-Oil Emulsions. API Drilling and Production Practice (1942): 148–153. Paper No. 42-148.