Decision Criterion for Acid-Stimulation Method in Carbonate Reservoirs: Matrix Acidizing or Acid Fracturing?
- Mateus Palharini Schwalbert (Petrobras) | Murtada Saleh Aljawad (King Fahd University of Petroleum and Minerals) | Alfred Daniel Hill (Texas A&M University) | Ding Zhu (Texas A&M University)
- Document ID
- Society of Petroleum Engineers
- SPE Journal
- Publication Date
- October 2020
- Document Type
- Journal Paper
- 2,296 - 2,318
- 2020.Society of Petroleum Engineers
- acid fractured well productivity, acid stimulation, matrix acidizing, acid fracturing
- 25 in the last 30 days
- 135 since 2007
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Most wells in carbonate reservoirs are stimulated. Because of their low cost and simpler operations, acid-stimulation methods are usually preferred if they are sufficient. Matrix acidizing can effectively stimulate carbonate reservoirs, often resulting in skin factors on the order of –3 to –4. In low confining stress and hard rocks, acid fracturing can yield better results than matrix acidizing. However, acid fracturing is less effective in high permeability, high confining stress, or soft rocks. There is a combination of parameters, among them permeability, confining stress, and rock geomechanical properties, that can be used as criteria to decide whether matrix acidizing or acid fracturing is the best acid-stimulation technique for a given scenario.
This study compares the productivity of matrix-acidized and acid-fractured wells in carbonate reservoirs. The criterion used to decide the preferred method is the largest productivity obtained using the same volume of acid for both operations. The productivity of the acid-fractured wells is estimated using a fully coupled acid-fracturing simulator, which integrates the geomechanics (fracture propagation), pad and acid transport, heat transfer, temperature effect on reaction rate, effect of wormhole propagation on acid leakoff, and finally calculates the well productivity by simulating the flow in the reservoir toward the acid fracture. Using this simulator, the acid-fracturing operation is optimized, resulting in the operational conditions (injection rate, type of fluid, amount of pad, and so forth) that lead to the best possible acid fracture that can be created with a given amount of acid. The productivity of the matrix-acidized wells is estimated using the most recent wormhole-propagation models scaled up to field conditions.
Results are presented for different types of rock and reservoir scenarios, such as shallow and deep reservoirs, soft and hard limestones, chalks, and dolomites. Most of the presented results considered vertical wells. A theoretical extension to horizontal wells is also presented using analytical considerations. For each type of reservoir rock and confining stress, there is a cutoff permeability less than which acid fracturing results in a more productive well; at higher than this cutoff permeability, matrix acidizing should be preferred. This result agrees with the general industry practice, and the estimated productivity agrees with the results obtained in the field. However, the value of the cutoff permeability changes for each case, and simple equations for calculating it are presented. For example, for harder rocks or shallower reservoirs, acid fracturing is more efficient up to higher permeabilities than in softer rocks or at deeper depths.
This method provides an engineered criterion to decide the best acid-stimulation method for a given carbonate reservoir. The decision criterion is presented for several different scenarios. A simplified concise analytical decision criterion is also presented: a single dimensionless number that incorporates all pertinent reservoir properties and determines which stimulation method yields the most productive well, without needing any simulations.
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Abass, H. H., Al-Mulhem, A. A., Alqam, M. H. et al. 2006. Acid Fracturing or Proppant Fracturing in Carbonate Formation? A Rock Mechanics View. Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 24–27 September. SPE-102590-MS. https://doi.org/10.2118/102590-MS.
Al Jawad, M. S. 2018. Development of a Fully Integrated Acid Fracture Model. PhD dissertation, Texas A&M University, College Station, Texas, USA (August 2018).
Aljawad, M. S., Palharini Schwalbert, M., Zhu, D. et al. 2019. Improving Acid Fracture Design in Dolomite Formations Utilizing a Fully Integrated Acid Fracture Model. J Pet Sci Eng 184 (January): 106481. https://doi.org/10.1016/j.petrol.2019.106481.
Aljawad, M. S., Palharini Schwalbert, M., Zhu, D. et al. 2020. Optimizing Acid Fracture Design in Calcite Formations: Guidelines Using a Fully Integrated Model. SPE Prod & Oper 35 (1): 161–177. SPE-198912-PA. https://doi.org/10.2118/198912-PA.
Ali, M. T. and Nasr-El-Din, H. A. 2018. A Robust Model To Simulate Dolomite-Matrix Acidizing. SPE Prod & Oper 34 (1): 109–129. SPE-191136-PA. https://doi.org/10.2118/191136-PA.
Azevedo, C. T., Rosolen, M. A., Rocha, J. D. H. et al. 2010. Challenges Faced To Execute Hydraulic Fracturing in Brazilian Pre-Salt Wells. Paper presented at the 44th US Rock Mechanics Symposium and 5th US-Canada Rock Mechanics Symposium, Salt Lake City, Utah, USA, 27–30 June. ARMA-10-212.
Babu, D. K. and Odeh, A. S. 1989. Productivity of a Horizontal Well (includes associated papers 20306, 20307, 20394, 20403, 20799, 21307, 21610, 21611, 21623, 21624, 25295, 25408, 26262, 26281, 31025, and 31035). SPE Res Eng 4 (4): 417–421. SPE-18298-PA. https://doi.org/10.2118/18298-PA.
Ben-Naceur, K. and Economides, M. J. 1989. Design and Evaluation of Acid Fracturing Treatments. Paper presented at the Low Permeability Reservoirs Symposium, Denver, Colorado, USA, 6–8 March. SPE-18978-MS. https://doi.org/10.2118/18978-MS.
Buijse, M. A. and Glasbergen, G. 2005. A Semi-Empirical Model To Calculate Wormhole Growth in Carbonate Acidizing. Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, USA, 9–12 October. SPE-96892-MS. https://doi.org/10.2118/96892-MS.
Burton, R. C., Nozaki, M., Zwarich, N. R. et al. 2018. Improved Understanding of Acid Wormholing in Carbonate Reservoirs Through Laboratory Experiments and Field Measurements. Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, USA, 24–26 September. SPE-191625-MS. https://doi.org/10.2118/191625-MS.
Cash, R., Zhu, D., and Hill, A. D. 2016. Acid Fracturing Carbonate-Rich Shale: A Feasibility Investigation of Eagle Ford Formation. Paper presented at the SPE Asia Pacific Hydraulic Fracturing Conference, Beijing, China, 24–26 August. SPE-181805-MS. https://doi.org/10.2118/181805-MS.
Daneshy, A., Valkó, P., and Norman, L. 1998. Well Stimulation. In Petroleum Well Construction, first edition, ed. M. J. Economides, L. T. Watters, and S. Dunn-Norman, Chap. 17. Chichester, New York, USA: Wiley.
De Rozieres, J. 1994. Measuring Diffusion Coefficients in Acid Fracturing Fluids and Their Application to Gelled and Emulsified Acids. Paper presented at the SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, USA, 25–28 September. SPE-28552-PA. https://doi.org/10.2118/28552-MS.
Deng, J., Mou, J., Hill, A. D. et al. 2012. A New Correlation of Acid-Fracture Conductivity Subject to Closure Stress. SPE Prod & Oper 27 (2): 158–169. SPE-140402-PA. https://doi.org/10.2118/140402-PA.
Dietz, D. N. 1965. Determination of Average Reservoir Pressure from Build-Up Surveys. J Pet Technol 17 (8): 955–959. SPE-1156-PA. https://doi.org/10.2118/1156-PA.
Earlougher, R. C. Jr., Ramey, H. J. Jr., Miller, F. G. et al. 1968. Pressure Distributions in Rectangular Reservoirs. J Pet Technol 20 (2): 199–208. SPE-1956-PA. https://doi.org/10.2118/1956-PA.
Economides, M. J. and Nolte, K. G. 2000. Reservoir Stimulation, third edition. London, UK: John Wiley & Sons.
Economides, M. J., Oligney, R., and Valkó, P. 2002. Unified Fracture Design: Bridging the Gap between Theory and Practice. Alvin, Texas, USA: Orsa Press.
Furui, K., Burton, R. C., Burkhead, D. W. et al. 2012. A Comprehensive Model of High-Rate Matrix-Acid Stimulation for Long Horizontal Wells in Carbonate Reservoirs: Part I—Scaling Up Core-Level Acid Wormholing to Field Treatments. SPE J. 17 (1): 271–279. SPE-134265-PA. https://doi.org/10.2118/134265-PA.
Furui, K., Zhu, D., and Hill, A. D. 2002. A Rigorous Formation Damage Skin Factor and Reservoir Inflow Model for a Horizontal Well. Paper presented at the International Symposium and Exhibition on Formation Damage, Lafayette, Louisiana, USA, 20–21 February. SPE-74698-MS. https://doi.org/10.2118/74698-MS.
Gringarten, A. C. 1978. Reservoir Limit Testing for Fractured Wells. Paper presented at the SPE Annual Fall Technical Conference and Exhibition, Houston, Texas, USA, 1–3 October. SPE-7452-MS. https://doi.org/10.2118/7452-MS.
Hoefner, M. L. and Fogler, H. S. 1988. Pore Evolution and Channel Formation During Flow and Reaction in Porous Media. AIChE Journal 34 (1): 45–54. https://doi.org/10.1002/aic.690340107.
Jeon, J., Bashir, M. O., Liu, J. et al. 2016. Fracturing Carbonate Reservoirs: Acidising Fracturing or Fracturing with Proppants? Paper presented at the SPE Asia Pacific Hydraulic Fracturing Conference, Beijing, China, 24–26 August. SPE-181821-MS. https://doi.org/10.2118/181821-MS.
Meyer, B. R. and Jacot, R. H. 2005. Pseudosteady-State Analysis of Finite Conductivity Vertical Fractures. Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, USA, 9–12 October. SPE-95941-MS. https://doi.org/10.2118/95941-MS.
Neumann, L. F. 2011. Experimental Investigation of the Building, Visualization, and Evaluation of Acid Fracture Conductivity on Microbial Carbonates (Investigação Experimental Sobre a Geração, Visualização e Avaliação da Condutividade de Fraturas Ácidas em Carbonatos Microbiais). Master's thesis, Universidade Estadual de Campinas, Campinas, Brazil.
Neumann, L. F., De Oliveira, T. J. L., Sousa, J. L. A. O. et al. 2012. Building Acid Frac Conductivity in Highly-Confined Carbonates. Paper presented at the SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, USA, 6–8 February. SPE-152164-MS. https://doi.org/10.2118/152164-MS.
Nierode, D. E. and Kruk, K. F. 1973. An Evaluation of Acid Fluid Loss Additives, Retarded Acids, and Acidized Fracture Conductivity. Paper presented at the Fall Meeting of the Society of Petroleum Engineers of AIME, Las Vegas, Nevada, USA, 30 September–3 October. SPE-4549-MS. https://doi.org/10.2118/4549-MS.
Oliveira, T. J. L., Neumann, L. F., and Azevedo, C. T. 2014. Acid or Propped Fracturing in Deep Carbonates? Experiments and Field Results. Paper presented at the SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 26–28 February. SPE-168129-MS. https://doi.org/10.2118/168129-MS.
Palharini Schwalbert, M. 2019. Comprehensive Analysis of Acid Stimulation in Carbonates. PhD dissertation, Texas A&M University, College Station, Texas, USA (August 2019).
Palharini Schwalbert, M., Hill, A. D., and Zhu, D. 2019a. Skin-Factor Equations for Anisotropic Wormhole Networks and Limited-Entry Completions. SPE Prod & Oper 34 (3): 586–602. SPE-189486-PA. https://doi.org/10.2118/189486-PA.
Palharini Schwalbert, M., Hill, A. D., and Zhu, D. 2019b. A New Up-Scaled Wormhole Model Grounded on Experimental Results and in 2-Scale Continuum Simulations. Paper presented at the SPE International Conference on Oilfield Chemistry, Galveston, Texas, USA, 8–9 April. SPE-193616-MS. https://doi.org/10.2118/193616-MS.
Roberts, L. D. and Guin, J. A. 1975. A New Method for Predicting Acid Penetration Distance. SPE J. 15 (4): 277–286. SPE-5155-PA. https://doi.org/10.2118/5155-PA.
Schechter, R. S. 1992. Oil Well Stimulation. Upper Saddle River, New Jersey, USA: Prentice-Hall.
Suleimenova, A., Wang, X., Zhu, D. et al. 2016. Comparative Study of Acid Fracturing and Propped Hydraulic Fracturing for a Tight Carbonate Formation. Paper presented at the SPE Europec/EAGE Conference and Exhibition, Vienna, Austria, 30 May–2 June. SPE-180114-MS. https://doi.org/10.2118/180114-MS.
Ugursal, A., Palharini Schwalbert, M., Zhu, D. et al. 2018. Acid Fracturing Productivity Model for Naturally Fractured Carbonate Reservoirs. Paper presented at the SPE International Hydraulic Fracturing Technology Conference and Exhibition, Muscat, Oman, 16–18 October. SPE-191433-18IHFT-MS. https://doi.org/10.2118/191433-18IHFT-MS.
Vos, B., de Pater, C. J., Cook, C. C. et al. 2007. Well Productivity in North Sea Chalks Related to Completion and Hydraulic Fracture Stimulation Practices. Paper presented at the European Formation Damage Conference, Scheveningen, The Netherlands, 30 May–1 June. SPE-107793-MS. https://doi.org/10.2118/107793-MS.
Wang, Y., Hill, A. D., and Schechter, R. S. 1993. The Optimum Injection Rate for Matrix Acidizing of Carbonate Formations. Paper presented at the SPE Annual Technical Conference and Exhibition, Houston, Texas, USA, 3–6 October. SPE-26578-PA. https://doi.org/10.2118/26578-MS.