Acid Wormholing in Multistage Acid Fractured Wells Completed in Tight Naturally Fractured Dolomite Formation: Benefits and Impacts on Acid Fracturing Stimulation Design
- Khaled Aldhayee (Texas A&M University) | Mahmoud T. Ali (Texas A&M University) | Hisham A. Nasr-El-Din (Texas A&M University)
- Document ID
- Society of Petroleum Engineers
- SPE International Hydraulic Fracturing Technology Conference and Exhibition, 16-18 October, Muscat, Oman
- Publication Date
- Document Type
- Conference Paper
- 2018. Society of Petroleum Engineers
- 4.1 Processing Systems and Design, 5.8.7 Carbonate Reservoir, 5.5 Reservoir Simulation, 3 Production and Well Operations, 4 Facilities Design, Construction and Operation, 2.6 Acidizing, 4.3.4 Scale, 4.1.2 Separation and Treating, 2 Well completion, 5 Reservoir Desciption & Dynamics, 5.5.3 Scaling Methods
- Reactive Flow, Closed-Fracture Acidizing, Acid Fracturing, Wormholes Propagation Model, Multistage Acid Fracturing
- 2 in the last 30 days
- 203 since 2007
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Closed-fracture acidizing (CFA) technique has been proved to be a successful practice in stimulating tight carbonate formations. Acid is injected at rates lower than fracturing pressure to enhance the fracture conductivity and productivity. CFA operations are often associated with acid wormholing, promoted by acid leak-off in the formation. The objective of this study is to develop a model that represents these wormholes demonstrating their performance in enhancing the acid fracturing treatment in tight naturally fractured dolomite reservoirs under field conditions and investigate the effect of different parameters on acid wormholing during CFA.
The wormholes propagation is modeled by the two-scale continuum model by developing a 3D computational fluid dynamics (CFD) model including the fracture geometry, conductivity of the fracture and the reaction kinetics between the acid system and the formation. The formation that is utilized in this study is tight naturally fractured dolomite formation exhibits low transmissibility and a considerable degree of heterogeneity. Well geometry was investigated to analyze the effect of injection area in the closed fracture on acid wormholing. Sensitivity analysis was conducted to cover the effect of several factors including acid concentration, injection rate, formation permeability and fracture conductivity to depict the actual flow in the formation. The presence of natural fractures was studied with the emphasis on their orientation and direction with respect to the hydraulic fracture whether it is parallel or perpendicular. Model upscaling was investigated to come up with a qualitative relationship between the acid volumes used in CFA model and the acid volumes used in actual field scale.
Acid injection rates in the closed-fracture in CFA operations follow a similar trend as the acid performance curve in matrix acidizing in term of dissolution patterns where a face dissolution pattern at the injection inlet of fracture occurs at low and high injection rates. Higher acid concentration accelerates the reaction between the acid and rock matrix and yields faster results than the lower concentrations. Vertical wells exhibit larger injection area in contact with the closed-fracture than the horizontal wells, which promote larger propagation of these wormholes with less total inject volumes of acid during CFA. Formation permeability coupled with acid fracture conductivity have significant role in the acid volumes used in CFA that are required to deliver the acid certain distance in the formation, and it affect the wormholing density significantly. The presence of natural fractures in the parallel or transversal direction with respect to hydraulic fracture play a key role in generating flow networks between hydraulic fracture and natural fractures that are induced by the acid leakoff in the formation regardless of the intersected natural fractures with hydraulic fracture. Model upscaling demonstrates the relationship that clarifies the total acid volumes injected in actual field applications that have to be used in the design of optimum acid fracture stages in multistage acid fracturing and to estimate the optimum spacing between the stages which will maximize the performance of this completion.
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Abass, H. H.,Ortiz, I.,Khan, M. R.. 2007. Understanding Stress Dependent Permeability of Matrix, Natural Fractures, and Hydraulic Fractures in Carbonate Formations. Presented at the SPE Saudi Arabia Section Technical Symposium, Dhahran, Saudi Arabia, 7-8 May. SPE-110973-MS. http://dx.doi.org/10.2118Z110973-MS.
Akanni, O. O. and Nasr-El-Din, H. A. 2015. The Accuracy of Carbonate Matrix-Acidizing Models in Predicting Optimum Injection and Wormhole Propagation Rates. Presented at the SPE Middle East Oil & Gas Show and Conference. Manama, Bahrain, 8-11 March. SPE 172575-MS. http://dx.doi.org/10.2118/172575-MS.
Akanni, O. O.,Nasr-El-Din, H. A. and Gusain, D. 2017. A Computational Navier-Stokes Fluid Dynamics Simulation Study of Wormhole Propagation in Carbonate Matrix Acidizing and Analysis of Factors Influencing the Dissolution Process. SPE J. 22 (6): 2049—2066. SPE-187962-PA. http://dx.doi.org/10.2118/187962-PA.
Ali, M. T., and Nasr-El-Din, H. A. 2018a. A Robust Model To Simulate Dolomite-Matrix Acidizing. SPE Prod and Oper. SPE-191136-PA (in press; posted June 2018). http://dx.doi.org/10.2118/191136-PA.
AlOtaibi, F. M.,Al-Dahlan, M. N.,Rafie, M.. 2017. Successful Completion of the First Ten Multistage Acid Fracturing of an Oil Producer in Saudi Arabia. Presented at the Abu Dhabi International Petroleum Exhibition & Conference, Abu Dhabi, UAE, 13-16 November. SPE-188499-MS. https://dx.doi.org/10.2118/188499-MS.
Anderson, M. S. and Fredrickson, S. E. 1989. Dynamic Etching Tests Aid Fracture-Acidizing Treatment Design. SPE Prod Eng 4 (4): 443—449. SPE-16452-PA. http://dx.doi.org/10.2118/16452-PA.
Balakotaiah, V. and West, D. H. 2002 Shape Normalization and Analysis of Mass Transfer Controlled Regime in Catalytic Monoliths. Chem Eng Sci 57 (8): 1269—1286. http://dx.doi.org/10.1016/S0009-2509(02)00059-3.
Bartko, K. M.,Conway, M. W.,Krawietz, T. E.. 1992. Field and Laboratory Experience in Closed Fracture Acidizing the Lisburne Field, Prudhoe Bay, Alaska. Presented at the SPE Annual Technical Conference and Exhibition, Washington, D.C., 4-7 October. SPE-24855-MS. http://dx.doi.org/10.2118/24855-MS.
Buijse, M. A. 2000. Understanding Wormholing Mechanisms Can Improve Acid Treatments in Carbonate Formations. SPE Prod & Oper 15 (3): 168–175. SPE-38166-MS. http://dx.doi.org/10.2118/38166-MS.
De Oliveira, T.,De Melo, A.,Oliveira, J.. 2012. Numerical Simulation of the Acidizing Process and PVBT Extraction Methodology Including Porosity/Permeability and Mineralogy Heterogeneity. Presented at the International Symposium and Exhibition on Formation Damage Control. Lafayette, Louisiana. 15-17 January. SPE 151823-MS. http://dx.doi.org/10.2118/151823-MS.
Fredrickson, S. E. 1986. Stimulating Carbonate Formations Using a Closed Fracture Acidizing Technique. Presented at the SPE East Texas Regional Meeting, Tyler, Texas, 21-22 April. SPE-14654-MS. https://dx.doi.org/10.2118/14654-MS.
Garzon, F. O.,Solares, J. R.,Ramanathan, V.. 2008. Long Term Evaluation of an Innovative Acid System for Fracture Stimulation of Carbonate Reservoirs in Saudi Arabia. Presented at the International Petroleum Technology Conference, Kuala Lumpur, Malaysia, 3-5 December. IPTC-12668-MS. http://dx.doi.org/10.2523/IPTC-12668-MS.
Gupta, N. and Balakotaiah, V. 2001. Heat and Mass Transfer Coefficients in Catalytic Monoliths. Chem Eng Sci 56 (16): 4771–4786. http://dx.doi.org/10.1016/S0009-2509(01)00134-8.
Inda, A.,Steffani, O.,Soriano, E.. 2009. Field Development and Productivity Improvement in Offshore Mexico - Engineering and Laboratory Synergistic Approach to Carbonate Fracture Acidizing. Presented at the 8th European Formation Damage Conference, Scheveningen, The Netherlands, 27-29 May. SPE-121928-MS. http://dx.doi.org/10.2118/121928-MS.
Jahediesfanjani, H., and Civan, F. 2006. Improving Performance of the Naturally Fractured Carbonate Reservoirs by Means of the Various Stimulation and Completion Techniques. Presented at the SPE International Oil Conference and Exhibition, Cancun, Mexico, 31 August-2 September. SPE-103986-MS. http://dx.doi.org/10.2118/103986-MS.
Maheshwari, P. and Balakotaiah, V. 2013. Comparison of Carbonate HCl Acidizing Experiments with 3D Simulations. SPE Prod & Oper 28 (4): 402–413. SPE-164517-PA http://dx.doi.org/10.2118/164517-PA.
McDuff, D.,Claiborne, E.,Zielinski, M.. 2016. An Engineered Approach to Acid Stimulation Strategies for Wells in the Kurdistan Region of Iraq. Presented at the Abu Dhabi International Petroleum Exhibition & Conference, Abu Dhabi, UAE, 7-10 November. SPE-182888-MS. https://dx.doi.org/10.2118/182888-MS.
Mofti, M.,Al-Othman, M.,Alboueshi, A.. 2018. First Fully Successful Application of a Multistage Acid Fracturing Operation to Stimulate a Carbonate Formation, Resulting in the Implementation in Other Wells in the Mature Bahrah Field, North Kuwait. Presented at the SPE/IADC Middle East Drilling Technology Conference and Exhibition, Abu Dhabi, UAE, 29-31 January. SPE-189353-MS. https://dx.doi.org/10.2118/189353-MS.
Mou, J.,Yu, X.,Wang, L.. 2018. Effect of Natural Fractures on Wormhole-Propagation Behavior. SPEProd and Oper. SPE-191148-PA (in press; posted August 2018). https://dx.doi.org/10.2118/191148-PA.
Mou, J.,Zhang, S., 2015. Modeling acid leakoff during multistage alternate injection of pad and acid in acid fracturing. J Natural Gas Sci Eng 26: 1161–1173. https://dx.doi.org/10.1016/j.jngse.2015.08.007.
Nasr-El-Din, H. A.,Solares, J. R.,Al-Zahrani, A. A.. 2009. Acid Fracturing of Gas Wells Using Solid Acid: Lessons Learned From First Field Application. SPE Prod & Oper 24 (2): 320–335. SPE-110895-PA. http://dx.doi.org/10.2118/110895-PA.
Nnanna, E. J., and Ajienka, J. A. 2005. Critical Success Factors for Well Stimulation. Presented at the SPE Nigeria Annual International Conference and Exhibition, Abuja, Nigeria, 1-3 August. SPE-98823-MS. http://dx.doi.org/10.2118/98823-MS.
Panga, M. K. R., Balakotaiah, V., and Ziauddin, M. 2002. Modeling, Simulation and Comparison of Models for Wormhole Formation during Matrix Stimulation of Carbonates. Presented at the SPE Annual Technical Conference and Exhibition. San Antonio, Texas. 29 September - 2 October. SPE 77369-MS http://dx.doi.org/10.2118/77369-MS.
Panga, M. K. R., Ziauddin, M., and Balakotaiah, V. 2005. Two-Scale Continuum Model for Simulation of Wormholes in Carbonate Acidization. AIChE J. 51 (12): 3231–3248. http://dx.doi.org/10.1002/aic.10574.
Pournik, M.,Nasr-El-Din, H.A., and Mahmoud, M.A. 2011. A Novel Application of Closed-Fracture Acidizing. SPE Prod & Oper 26 (1): 18—29. SPE-124874-PA. http://dx.doi.org/10.2118/124874-PA.
Sarma, D. K.,Pal, T.,Kumar, D.. 2017. Application of Closed Fracture Acidizing for Stimulation of Tight Carbonate Reservoir in Mumbai Offshore. Presented at the SPE Oil and Gas India Conference and Exhibition, Mumbai, India, 4-6 April. SPE-185344-MS. https://dx.doi.org/10.2118/185344-MS.
Schwalbert, P.,Zhu, D., and Hill, A. D. 2017. Extension of an Empirical Wormhole Model for Carbonate Matrix Acidizing Through Two-Scale Continuum 3D Simulations. Presented at the SPE Europec featured at 79th EAGE Conference and Exhibition, Paris, France, 12-15 June. SPE-185788-MS. http://dx.doi.org/10.2118/185788-MS.
Sizer, J. P.,Moullem, A. S., and Abou-Sayed, I. S. 1991. Evaluation of Closed Fracture Acidizing Performed in a Tight Limestone Formation. Presented at the Middle East Oil Show, Bahrain, 16-19 November. SPE-21440-MS. http://dx.doi.org/10.2118/21440-MS.
Sollman, M. Y.,Hunt, J. L., and Daneshi, T. 1990. Well-Test Analysis Following a Closed-Fracture Acidizing Treatment. SPE Formation Evaluation 5 (4): 369–374. SPE-17972-PA. https://dx.doi.org/10.2118/17972-PA.
Ugursal, A.,Zhu, D., and Hill, A. D. 2018. Development of Acid Fracturing Model for Naturally Fractured Reservoirs. Presented at the SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, 23-25 January. SPE-189834-MS. https://dx.doi.org/10.2118/189834-MS.
Valko, P. P., and Economides, M. J. 1998. Heavy Crude Production from Shallow Formations: Long Horizontal Wells Versus Horizontal Fractures. Presented at the SPE International Conference on Horizontal Well Technology, Calgary, Alberta, 14 November. SPE-50421-MS. https://dx.doi.org/10.2118/50421-MS.
Wang, X.,Zou, H.,Zheng, X.. 2003. Optimization of Acid Fracturing to Improve Heavy Oil Production in Naturally Fractured Carbonates. Presented at the SPE Production and Operations Symposium, Oklahoma City, Oklahoma, 23-26 March. SPE-80897-MS. https://dx.doi.org/10.2118/80897-MS.
Wu, Y.,Salama, A., and Sun, S. 2015. Parallel simulation of wormhole propagation with the Darcy-Brinkman-Forchheimer framework. Computers and Geotechnics 69: 564–577. https://dx.doi.org/10.1016/j.compgeo.