Effect of Droplet Size on the Reaction Kinetics of Emulsified Acid With Calcite
- Saleh H. Al-Mutairi (Saudi Aramco) | Hisham A. Nasr-El-Din (Texas A&M University) | Alfred D. Hill (Texas A&M University) | Ali Al-Aamri (Saudi Aramco)
- Document ID
- Society of Petroleum Engineers
- SPE Journal
- Publication Date
- December 2009
- Document Type
- Journal Paper
- 606 - 616
- 2009. Society of Petroleum Engineers
- 4.1.5 Processing Equipment, 2.5.2 Fracturing Materials (Fluids, Proppant), 4.2.3 Materials and Corrosion, 5.6.5 Tracers, 3.2.4 Acidising, 3.3.1 Production Logging, 5.8.7 Carbonate Reservoir, 1.8 Formation Damage, 4.1.2 Separation and Treating, 3 Production and Well Operations
- acidizing, droplet size distribution, acid fracturing, reaction kinetics of emulsified acids, acid-in-oil emulsion, emulsified acid
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- 643 since 2007
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Unlike other acid systems, such as gelled and viscoelastic surfactant-based (VES) acids, where the mobility of hydrogen ion controls the overall rate of the reaction, emulsified acid/calcite reaction involves the transport of acid droplets in the diesel phase to the rock surface, breaking of acid droplets, and then the actual reaction on the surface. A limited number of papers have been published on the reaction kinetics of emulsified acid. However, none of the published work considered the effect of acid droplet size on the reaction of emulsified acid. The objective of this work is to examine the effect of the acid droplet size on the reaction rate of emulsified acid with calcite.
The acid was 15 wt% HCl emulsified in diesel with 70 to 30 acid-to-diesel volume ratio. The emulsifier concentration was varied from 1 to 10 gpt. All emulsions were characterized by measuring the droplet size distribution, viscosity, and thermal stability. Diffusivities were measured using the rotating disk device. The experiments were carried out at 25, 50, and 85°C, under 1,000 psi pressure, and disk rotational speeds from 100 to 1,000 rev/min. Samples of the reacting acid were collected and analyzed to measure calcium concentration in the reactor.
The effect of the acid droplet size on the overall reaction rate was significant. The diffusion rate of acid droplets to the surface of the disk was found to decrease with increasing emulsifier concentration because of higher viscosities and smaller droplet sizes. The effective diffusion coefficient of emulsified acid was found to increase linearly with the average droplet size. Emulsions with low emulsifier concentrations (1 gpt) had average droplet sizes of nearly 13 µm. These emulsions were found to have high effective diffusion coefficients (5.093×10-9 cm2/s) and low retardation. On the other hand, emulsions with high emulsifier concentrations (10 gpt) had smaller average droplet sizes (nearly 6 µm) and found to have low effective diffusion coefficients (4.905×10-11 cm2/s) and high retardations.
The new sets of data can be used to determine the optimum emulsified acid formulation to yield deeper acid penetration in the formation. It is suggested that droplet size can be adjusted to produce the desired diffusion coefficients for acid fracturing treatments.
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Al-Mohammad, A.M., Nasr-El-Din, H.A., Al-Aamri, A.M., and Al-Fuwaires, O.2006. Reaction of Calcite withSurfactant-Based Acids. Paper SPE 102838 presented at the SPE AnnualTechnical Conference and Exhibition, San Antonio, Texas, USA, 24-27 September.doi: 10.2118/102838-MS.
Al-Mutairi, S.H., Hill, A.D., and Nasr-El-Din, H.A. 2008. Effect of Droplet Size, EmulsifierConcentration, and Acid-Volume Fraction on the Rheological Properties andStability of Emulsified Acids. SPE Prod & Oper 23(4): 484-497. SPE-107741-PA. doi: 10.2118/107741-PA.
Becher, P. 1957. Emulsions: Theory and Practice, 52. New York:Reinhold Publishing.
Boomer, D.R., McCune, C.C., and Fogler, H.S. 1972. Rotating disk apparatus forreaction rate studies in corrosive liquid environments. Review ofScientific Instruments 43 (2): 225-229. doi:10.1063/1.1685599.
Buijse, M.A. and van Domelen, M.S. 1998. Novel Application of Emulsified Acidsto Matrix Stimulation of Heterogeneous Formations. Paper SPE 39583presented at the SPE Formation Damage Control Conference, Lafayette, Louisiana,USA, 18-19 February. doi: 10.2118/39583-MS.
Conway, M.W., Asadi, M., Penny, G., and Chang, F. 1999. A Comparative Study ofStraight/Gelled/Emulsified Hydrochloric Acid Diffusivity Coefficient UsingDiaphragm Cell and Rotating Disk. Paper SPE 56532 presented at the SPEAnnual Technical Conference and Exhibition, Houston, 3-6 October. doi:10.2118/56532-MS.
de Groote, M. 1933. Process for Increasing the Output of Oil Wells. U.S.Patent No. 1,922,154.
de Rozieres, J., Chang, F.F., and Sullivan, R.B. 1994. Measuring Diffusion Coefficients inAcid Fracturing Fluids and Their Application to Gelled and EmulsifiedAcids. Paper SPE 28552 presented at the SPE Annual Technical Conference andExhibition, New Orleans, 25-28 September. doi: 10.2118/28552-MS.
Exner, F.M. 1900. Notiz zu Brown's Molecularbewegung. Annalen derPhysik 2 (8): 843-847.
Fredd, C.N. 1998. The Influence of Transport and Reaction on WormholeFormation in Carbonate Porous Media: A Study of Alternative Stimulation Fluids.PhD dissertation, University of Michigan, Ann Arbor, Michigan.
Fredd, C.N. and Fogler, H.S. 1998. The kinetics of calcitedissolution in acetic acid solutions. Chem. Eng. Sci. 53 (22): 3863-3874. doi: 10.1016/S0009-2509(98)00192-4.
Fuks, D., Pelleg, J., Rashkeev, S., and Dorfman, S. 1994. The curvature of the self-diffusionArrhenius plot through the mono-vacancy mechanism. Zeitschrift fürPhysik B Condensed Matter 95 (2): 189-195. doi:10.1007/BF01312191.
Gibbs, G.B. 1965. On the temperaturedependence of the activation energy for diffusion. Acta Metallurgica 13 (8): 926-927. doi: 10.1016/0001-6160(65)90085-4.
Gregory, D.P. and Riddiford, A.C. 1956. Transport to the Surface of aRotating Disk. J. Chem. Soc. Abstr. 33: 3756-3764.
Hansford, G.S. and Litt, M. 1968. Mass transport from arotating disk into power-law liquids. Chem. Eng. Sci. 23 (8): 849-864. doi: 10.1016/0009-2509(68)80020-X.
Hoefner, M.L. and Fogler, H.S. 1985. Effective Matrix Acid Stimulation ofCarbonates Using Microemulsions. Chemical Engineering Progress 81: 40-44.
Instruction Manual. Program "analysette 22" Laser-Particle-Sizer 32Bitfor Windows, edition 04/2002, Section 6.3, 50-57. 2002. Idar-Oberstein,Germany: Fritsch GmbH.
Kasza, P., Dziadkiewicz, M., and Czupski, M. 2006. From Laboratory Research toSuccessful Practice: A Case Study of Carbonate Formation Emulsified AcidTreatments. Paper SPE 98261 presented at the International Symposium andExhibition on Formation Damage Control, Lafayette, Louisiana, USA, 15-17February. doi: 10.2118/98261-MS.
Knorr, P. and Herzig, C. 1995. Tracer diffusion ofhafnium, niobium and zirconium in Hf-Nb alloys. Journal of Physics:Condensed Matter 7 (48): 9185-9200. doi:10.1088/0953-8984/7/48/009.
Levich, V.G. 1962. Physicochemical Hydrodynamics, 78. EnglewoodCliffs, New Jersey: Prentice-Hall Inc.
Li, Y., Sullivan, R.B., de Rozieres, J., Gaz, G.L., and Hinkel, J.J. 1993.An Overview of Current AcidFracturing Technology With Recent Implications for Emulsified Acids. PaperSPE 26581 presented at the SPE Annual Technical Conference and Exhibition,Houston, 3-6 October. doi: 10.2118/26581-MS.
Lund, K., Fogler, H.S., McCune, C.C., and Ault, J.W. 1975. Acidization—II. Thedissolution of calcite in hydrochloric acid. Chem. Eng. Sci. 30 (8): 825-835. doi: 10.1016/0009-2509(75)80047-9.
Nasr-El-Din, H.A., Al-Anazi, H.A., and Mohamed, S.K. 2000. Stimulation of Water Disposal WellsUsing Acid-in-Diesel Emulsions--Case Histories. SPE Prod & Fac 15 (3): 176-182. SPE-65069-PA. doi: 10.2118/65069-PA.
Nasr-El-Din, H.A., Al-Mohammad, A., Al-Aamri, A., and Al-Fuwaires, O. 2008b.Reaction of Gelled Acids WithCalcite. SPE Prod & Oper 23 (3): 353-361.SPE-103979-PA. doi: 10.2118/103979-PA.
Nasr-El-Din, H.A., Al-Mohammad, A.M., Al-Aamri, A.D., Al-Fahad, M.A, andChang, F.F. 2009. QuantitativeAnalysis of Reaction-Rate Retardation in Surfactant-Based Acids. SPEProd & Oper 24 (1): 107-116. SPE-107451-PA. doi:10.2118/107451-PA.
Nasr-El-Din, H.A., Solares, J.R., Al-Mutairi, S.H., and Mahoney, M.D. 2001.Field Application of EmulsifiedAcid-Based System to Stimulate Deep Sour Gas Reservoirs in Saudi Arabia.Paper SPE 71693 presented at the SPE Annual Technical Conference andExhibition, New Orleans, 30 September-3 October. doi: 10.2118/71693-MS.
Navarrete, R.C., Holms, B.A., McConnell, S.B., and Linton, D.E. 1998a. Emulsified Acid Enhances WellProduction in High-Temperature Carbonate Formations. Paper SPE 50612presented at the European Petroleum Conference, The Hague, 20-22 October. doi:10.2118/50612-MS.
Navarrete, R.C., Miller, M.J., and Gordon, J.E. 1998b. Laboratory and Theoretical Studiesfor Optimization of Acid Fracture Stimulation. Paper SPE 39776 presented atthe SPE Permian Basin Oil and Gas Recovery Conference, Midland, Texas, USA,23-26 March. doi: 10.2118/39776-MS.
Nierode, D.E. and Kruk, K.F. 1973. An Evaluation of Acid Fluid LossAdditives, Retarded Acids, and Acidized Fracture Conductivity. Paper SPE4549 presented at the Fall Meeting of the Society of Petroleum Engineers ofAIME, Las Vegas, Nevada, USA, 30 September-3 October. doi: 10.2118/4549-MS.
Nierode, D.E. and Williams, B.B. 1971. Characteristics of Acid Reaction inLimestone Formations. SPE J. 11 (4): 406-418;Trans., AIME, 251. SPE-3101-PA. doi: 10.2118/3101-PA.
Roberts, L.D. and Guin, J.A. 1974. The Effect of Surface Kinetics inFracture Acidizing. SPE J. 14 (4): 385-395;Trans., AIME, 257. SPE-4349-PA. doi: 10.2118/4349-PA.
Roberts, L.D. and Guin, J.A. 1975. A New Method for Predicting AcidPenetration Distance. SPE J. 15 (4): 277-286.SPE-5155-PA. doi: 10.2118/5155-PA.
Taylor, K.C., Al-Ghamdi, A.H., and Nasr-El-Din, H.A. 2004. Effect of Additives on the AcidDissolution Rates of Calcium and Magnesium Carbonates. SPE J. 19 (3): 122-127. SPE-80256-PA. doi: 10.2118/80256-PA.
Taylor, K.C., Nasr-El-Din, H.A., and Mehta, S. 2006. Anomalous Acid Reaction Rates inCarbonate Reservoir Rocks. SPE J. 11 (4): 488-496.SPE-89417-PA. doi: 10.2118/89417-PA.
Williams, B.B. and Nierode, D.E. 1972. Design of Acid FracturingTreatments. J. Pet Tech 24 (7): 849-859; Trans.,AIME, 253. SPE-3720-PA. doi: 10.2118/3720-PA.