Concepts in Cleanup of Fracturing Fluids Used in Conventional Reservoirs: A Literature Review
- Ghaithan A. Al-Muntasheri (Saudi Aramco) | Leiming Li (Aramco Services Company: Aramco Research Center-Houston) | Feng Liang (Aramco Services Company: Aramco Research Center-Houston) | Ahmed M. Gomaa (Saudi Aramco)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- May 2018
- Document Type
- Journal Paper
- 196 - 213
- 2018.Society of Petroleum Engineers
- breaker, fracturing fluid, encapsulation, delay
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Fracturing fluids are used for transport and placement of proppants in hydraulic-fracturing operations. In the case of conventional reservoirs, sufficient fluid viscosity is needed to transport proppant. An ideal fracturing fluid should possess enough viscosity to suspend and carry proppant. After the proppant placement, the fluid viscosity should drop to facilitate an efficient and quick fracture cleanup. This ensures adequate fracture conductivity. Most of the fracturing fluids used in these operations are dependent on crosslinking reactions between polymers and crosslinkers. Breaker technologies such as oxidizers, enzymes, fluoride compounds, oxides, vitamins, and decrosslinking agents are used to break the crosslinked polymer-based gels. These materials are added as components of the initial fracturing-fluids recipe. This paper will focus on the available breaker technologies used for degrading and cleaning up fracturing fluids used for conventional reservoirs. Each breaker has its own operating mechanism and window of application in terms of temperature and pH. The design and selection of a breaker package will first require an understanding of how the fracturing fluid forms. The current review reveals the crosslinking mechanisms of various fracturing fluids. These include the crosslinking of biopolymers with borates, the crosslinking of synthetic and biopolymers with metals, and the crosslinking of phosphate esters with metals. In the acidizing of carbonate reservoirs, the use of viscous fluids is needed to allow diversion of acid to lower-permeability paths. Moreover, the high viscosity retards the reaction between the acid and the rock, and this ensures deep penetration of the stimulation fluid. In this application, the viscosity develops as a response to the change in pH. Hydrocarbon fluids are used for hydraulically fracturing water-sensitive formations. Each of the aforementioned fracturing fluids has its own suitable breaker technology. For borate-crosslinked biopolymer gels, breakers such as oxidative and enzyme breakers can be used to reduce fluid viscosity by degrading polymer chains. An alternative approach to reduce viscosity of this type of fluid is the use of acids that lower the pH and decrosslink the fluid. A third route to reduce this fluid viscosity is by use of chelating agents and complexing agents. Lowering fluid viscosity alone may not sufficiently guarantee adequate proppant-pack and formation cleanup. It has been proved that low-viscosity fluids may still contain high-molecular-weight (MW) polymers that could severely damage formation and proppant pack. These high-MW polymers should be further broken into low-MW fragments with oxidizers or enzymes to achieve better production numbers. When metals are used to crosslink biopolymers and synthetic polymers, breakers such as oxidative breakers can still be effective. Acid fracturing fluids use fluoride-based breakers that can complex with the zirconium (Zr) and hence decrosslink the gel. When fracturing high-temperature wells, breakers can prematurely degrade the gel viscosity. This leads to less proppant placement and possibly screens out the proppant. As a result, the propped fracture becomes shorter and the well productivity will be less. To avoid this, breakers are encapsulated with materials that act as barriers between the breaker and fluid. The dissolution of the encapsulating material gives additional time for the gel to place the proppant. This paper reviews more than 100 papers and patents to summarize the experience and available knowledge in the area of using breakers for cleaning up fracturing fluids.
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Aksoy, G., Gomaa, A. M., Nasr-El-Din, H. A. et al. 2011. Evaluation of a New Liquid Breaker for Polymer-Based In-Situ Gelled Acids. Presented at the Brasil Offshore Conference and Exhibition, Macae, Brazil, 14–17 June. SPE-143447-MS. https://doi.org/10.2118/143447-MS.
Al-Muntasheri, G. A. 2014. A Critical Review of Hydraulic-Fracturing Fluids for Moderate- to Ultralow-Permeability Formations Over the Last Decade. SPE Prod & Oper 29 (4): 243–260. SPE-169552-PA. https://doi.org/10.2118/169552-PA.
Armstrong, C. D. and Gunawan, S. 2014. Well Treatment Fluids Containing an Ylide or a Vitamin B and Methods of Using The Same. US Patent Application No. 20,140,041,877.
Barati, R. and Liang, J. 2014. A Review of Fracturing Fluid Systems Used for Hydraulic Fracturing of Oil and Gas Wells. J. Appl. Polym. Sci. 131 (16): 40735. https://doi.org/10.1002/app.40735.
Barron, A. N., Hendrickson, A. R., and Wieland, D. R. 1962. The Effect of Flow on Acid Reactivity in a Carbonate Fracture. J Pet Technol 14 (4): 409–415. SPE-134-PA. https://doi.org/10.2118/134-PA.
Bennion, D. B., Thomas, F. B., Bietz, R. F. et al. 1996. Water and Hydrocarbon Phase Trapping in Porous Media-Diagnosis, Prevention and Treatment. J Can Pet Technol 35 (10): 29–36. PETSOC-96-10-02. https://doi.org/10.2118/96-10-02.
Boles, J. L., Metcalf, A. S., and Dawson, J. C. 1996. Coated Breaker for Crosslinked Acid. US Patent No. 5,497,830.
Brannon, H. D. and Tjon-Joe-Pin, R. M. 1994. Biotechnological Breakthrough Improves Performance of Moderate to High-Temperature Fracturing Applications. Presented at the SPE Annual Technical Conference and Exhibition, New Orleans, 25–28 September. SPE-28513-MS. https://doi.org/10.2118/28513-MS.
Brannon, H. D. and Tjon-Joe-Pin, R. M. 1995. Characterization of Breaker Efficiency Based Upon Size Distribution of Polymeric Fragments. Presented at the SPE Annual Technical Conference and Exhibition, Dallas, 22–25 October. SPE-30492-MS. https://doi.org/10.2118/30492-MS.
Brannon, H. D., Tjon-Joe-Pin, R. M., Carman, P. S. et al. 2003. Enzyme Breaker Technologies: A Decade of Improved Well Stimulation. Presented at the SPE Annual Technical Conference and Exhibition, Denver, 5–8 October. SPE-84213-MS. https://doi.org/10.2118/84213-MS.
Burnham, J. W., Briscoe, J. E., and Elphingstone, E. A. 1980a. Methods and Additives for Delaying the Release of Chemicals in Aqueous Fluids. US Patent No. 4,202,795.
Burnham, J. W., Harris, L. E., and McDaniel, B. W. 1980b. Developments in Hydrocarbon Fluids for High-Temperature Fracturing. J Pet Technol 32 (2): 217–220. SPE-7564-PA. https://doi.org/10.2118/7564-PA.
Caulfield, M. J., Qiao, G. G., and Solomon, D. H. 2002. Some Aspects of the Properties and Degradation of Polyacrylamides. Chem. Rev. 102 (9): 3067–3084. https://doi.org/10.1021/cr010439p.
Cawiezel, K. E. and Elbel, J. L. 1992. A New System for Controlling the Crosslinking Rate of Borate Fracturing Fluids. SPE Prod Eng 7 (3): 275–279. SPE-20077-PA. https://doi.org/10.2118/20077-PA.
Chauveteau, G., Tabary, R., Renard, M. et al. 1999. Controlling In-Situ Gelation of Polyacrylamides by Zirconium for Water Shutoff. Presented at the SPE International Symposium on Oilfield Chemistry, Houston, 16–19 February. SPE-50752-MS. https://doi.org/10.2118/50752-MS.
Church, D. C., Quisenberry, J. L., and Fox, K. B. 1981. Field Evaluation of Gelled Acid for Carbonate Formations. J Pet Technol 33 (12): 2471–2474. SPE-9753-PA. https://doi.org/10.2118/9753-PA.
Cikes, M., Cubric, S., and Moylashov, M. R. 1998. Formation Damage Prevention by Using an Oil-Based Fracturing Fluid in Partially Depleted Oil Reservoirs of Western Siberia. Presented at the SPE Formation Damage Control Conference, Lafayette, Louisiana, 18–19 February. SPE-39430-MS. https://doi.org/10.2118/39430-MS.
Clark, P. E. and Barkat, O. 1989. Hydraulic Fracturing Fluids: The Crosslinking of Hydroxypropyl Guar with Titanium Chelates. Presented at the SPE Eastern Regional Meeting, Morgantown, West Virginia, 24–27 October. SPE-19331-MS. https://doi.org/10.2118/SPE-19331-MS.
Conway, M. W., Almond, S. W., Briscoe, J. E. et al. 1983. Chemical Model for the Rheological Behavior of Crosslinked Fluid Systems. J Pet Technol 35 (2): 315–320. SPE-9334-PA. https://doi.org/10.2118/9334-PA.
Cramer, D. D., Dawson, J., and Ouabdesselam, M. 1991. An Improved Gelled Oil System for High-Temperature Fracturing Applications. Presented at the Low Permeability Reservoirs Symposium, Denver, 15–17 April. SPE-21859-MS. https://doi.org/10.2118/21859-MS.
Daccord, G., Lemanczyk, R., and Vercaemer, C. 1985. Method for Obtaining Gelled Hydrocarbon Compositions, the Compositions According to Said Method and Their Application in the Hydraulic Fracturing of Underground Formations. US Patent No. 4,507,213.
De Benedictis, F., Wang, X., and Qu, Q. 2010. Liquid Breaker for Acid Fracturing Fluids. US Patent No. 7,798,228.
de Kruijf, A. S., Roodhart, L. P., and Davies, D. R. 1993. Relation Between Chemistry and Flow Mechanics of Borate-Crosslinked Fracturing Fluids. SPE Prod & Fac 8 (3): 165–170. SPE-25206-PA. https://doi.org/10.2118/25206-PA.
DeVine, C. S., Wood, W. D., Shekarchian, M. et al. 2003. New Environmentally Friendly Oil-Based Stimulation Fluids. Presented at the SPE Annual Technical Conference and Exhibition, Denver, 5–8 October. SPE-84576-MS. https://doi.org/10.2118/84576-MS.
Economides, M. J. and Nolte, K. G. 2000. Reservoir Stimulation, third edition. New York City: John Wiley & Sons.
Elbel, J., Gulbis, J., King, M. T. et al. 1991. Increased Breaker Concentration in Fracturing Fluids Results in Improved Gas Well Performance. Presented at the SPE Production Operations Symposium, Oklahoma City, Oklahoma, 7–9 April. SPE-21716-MS. https://doi.org/10.2118/21716-MS.
Elgassier, M. M. and Stolyarov, S. M. 2008. Reasons for Oil-Based Hydraulic Fracturing in Western Siberia. Presented at the SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, 13–15 February. SPE-112092-MS. https://doi.org/10.2118/112092-MS.
Ely, J. W. 1989. Fracturing Fluids and Additives. In Recent Advances in Hydraulic Fracturing, Vol. 12. Richardson, Texas: Monograph Series, Society of Petroleum Engineers.
Fairless, C. M. and Joseph, W. 1986. Effective Well Stimulations with Gelled Methanol/Carbon Dioxide Fracturing Fluids. Presented at the SPE East Texas Regional Meeting, Tyler, Texas, 21–22 April. SPE-14656-MS. https://doi.org/10.2118/14656-MS.
Funkhouser, G. P., and Norman, L. R. 2003. Synthetic Polymer Fracturing Fluid for High-Temperature Applications. Presented at International Symposium on Oilfield Chemistry, Houston, 5–7 February. SPE-80236-MS. https://doi.org/10.2118/80236-MS.
Funkhouser, G. P., Holtsclaw, J., and Blevins, J. J. 2010. Hydraulic Fracturing Under Extreme HPHT Conditions: Successful Application of a New Synthetic Fluid in South Texas Gas Wells. Presented at the SPE Deep Gas Conference and Exhibition, Manama, Bahrain, 24–26 January. SPE-132173-MS. https://doi.org/10.2118/132173-MS.
Fyten, G., Houle, P., Taylor, R. S. et al. 2007. Total Phosphorus Recovery in Flowback Fluids After Gelled Hydrocarbon Fracturing Fluid Treatments. J Can Pet Technol 46 (12): 17–21. PETSOC-07-12-TN2. https://doi.org/10.2118/07-12-TN2.
Gall, B. L. and Raible, C. J. 1985. Molecular Size Studies of Degraded Fracturing Fluid Polymers. Presented at the SPE Oilfield and Geothermal Chemistry Symposium, Phoenix, Arizona, 9–11 April. SPE-13566-MS. https://doi.org/10.2118/13566-MS.
Gomaa, A. M. and Nasr-El-Din, H. A. 2010. New Insights into the Viscosity of Polymer-Based In-Situ Gelled Acids. SPE Prod & Oper 25 (3): 367–375. SPE-121728-PA. https://doi.org/10.2118/121728-PA.
Gulbis, J., King, M. T., Hawkins, G. W. et al. 1992. Encapsulated Breaker for Aqueous Polymeric Fluids. SPE Prod Eng 7 (1): 9–14. SPE-19433-PA. https://doi.org/10.2118/19433-PA.
Gunawan, S., Armstrong, C. D., and Qu, Q. 2012. Universal Breakers with Broad Polymer Specificity for Use in Alkaline, High-Temperature Fracturing Fluids. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 8–10 October. SPE-159396-MS. https://doi.org/10.2118/159396-MS.
Gunawan, S., Armstrong, C. D., and Qu, Q. 2014. Environmentally Responsible, Catalytic Breakers for Alkaline, High-Temperature Fracturing Fluids. Presented at the SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, 26–28 February. SPE-168204-MS. https://doi.org/10.2118/168204-MS.
Gupta, D. V. S. 2009. Unconventional Fracturing Fluids for Tight Gas Reservoirs. Presented at the SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, 19–21 January. SPE-119424-MS. https://doi.org/10.2118/119424-MS.
Gupta, D. V. S. and Carman, P. S. 2011. Fracturing Fluid for Extreme Temperature Conditions is Just as Easy as the Rest. Presented at the SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, 24–26 January. SPE-140176-MS. https://doi.org/10.2118/140176-MS.
Gupta, D. V. S. and Cooney, A. P. 1992. Encapsulations for Treating Subterranean Formations and Methods for the Use Thereof. US Patent No. 5,164,099.
Gupta, D. V. S. and Prasek, B. B. 1995. Method for Fracturing Subterranean Formations using Controlled Release Breakers and Compositions Useful Therein. US Patent No. 5,437,331.
Gupta, D. V. S., Niechwiadowicz, G., and Jerat, A. C. 2003. CO2 Compatible Non-Aqueous Methanol Fracturing Fluid. Presented at the SPE Annual Technical Conference and Exhibition, Denver, 5–8 October. SPE-84579-MS. https://doi.org/10.2118/84579-MS.
Gupta, D. V. S., Pakulski, M. K., Prasek, B. et al. 1992. High-pH-Tolerant Enzyme Breaker for Oilfield Applications. Presented at the Permian Basin Oil and Gas Recovery Conference, Midland, Texas, 18–20 March. SPE-23986-MS. https://doi.org/10.2118/23986-MS.
Hanes, R. E. Jr., Pauls, R. W., Griffin, D. E. et al. 2011. Compositions for Reducing the Viscosity of Treatment Fluids. US Patent No. 7,888,297.
Hanes, R. E. Jr., Weaver, J. D., and Slabaugh, B. F. 2006. Methods and Compositions for Reducing the Viscosity of Treatment Fluids. US Patent No. 7,082,995.
Harris, P. C. 1993. Chemistry and Rheology of Borate-Crosslinked Fluids at Temperatures to 300°F. J Pet Technol 45 (3): 264–269. SPE-24339-PA. https://doi.org/10.2118/24339-PA.
Hill, D.G. 2005. Gelled Acid. US Patent Application No. 20,050,065,041.
Hlidek, B. T., Meyer, R. K., Yule, K. D. et al. 2012. A Case for Oil-Based Fracturing Fluids in Canadian Montney Unconventional Gas Development. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 8–10 October. SPE-159952-MS. https://doi.org/10.2118/159952-MS.
Holtsclaw, J. and Funkhouser, G. P. 2010. A Crosslinkable Synthetic-Polymer System for High-Temperature Hydraulic-Fracturing Applications. SPE Drill & Compl 25 (4): 555–563. SPE-125250-PA. https://doi.org/10.2118/125250-PA.
Hossaini, M., Jabs, W., and Grisdale, J. 1989. Fracturing With Crosslinked Gelled Methanol: A New Approach to Well Stimulation. J Can Pet Technol 28 (5): 49–54. PETSOC-89-05-04. https://doi.org/10.2118/89-05-04.
Huddleston, D. A. 1989. Hydrocarbon Geller and Method for Making the Same. US Patent No. 4,877,894.
Jacobs, I. C. 1988. Encapsulated Breaker for Cross-linked Acid Gel, Fracture Acidizing Fluid Containing Same and Method of Use Thereof. US Patent No. 4,770,796.
Jennings, A. R. 1996. Fracturing Fluids–Then and Now. J Pet Technol 48 (7): 604–610. SPE-36166-JPT. https://doi.org/10.2118/36166-JPT.
Kesavan, S. and Prud’homme, R. K. 1992. Rheology of Guar and HPG Cross-Linked by Borate. Macromolecules 25 (7): 2026–2032. https://doi.org/10.1021/ma00033a029.
King, G. E. 2012. Hydraulic Fracturing 101: What Every Representative, Environmentalist, Regulator, Reporter, Investor, University Researcher, Neighbor and Engineer Should Know About Estimating Frac Risk and Improving Frac Performance in Unconventional Gas and Oil Wells. Presented at the SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, 6–8 February. SPE-152596-MS. https://doi.org/10.2118/152596-MS.
King, M. T. 1990. Method for Treating Subterranean Formations. US Patent No. 4,919,209.
Kolthoff, I. M. and Miller, I. K. 1951. The Chemistry of Persulfate. I. The Kinetics and Mechanism of the Decomposition of the Persulfate Ion in Aqueous Medium. J. Am. Chem. Soc. 73 (7): 3055–3059. https://doi.org/10.1021/ja01151a024.
Kramer, J., Prud’homme, R. K., Wiltzius, P. et al. 1988. Comparison of Galactomannan Crosslinking with Organotitanates and Borates. Colloid Polym. Sci. 266 (2): 145–155. https://doi.org/10.1007/BF01452812.
Laramay, S. B., George, C., and Pfeffer, H. A. III. 2011. Reducing the Viscosity of an Aqueous Fluid. US Patent No. 7,947,745.
Laramay, S. B., Shelley, R. F., and Hatcher, W. B. 1992. New Technology Improves the Performance of Borate Fluids in Low-Temperature Zones of the Belridge Field. Presented at the SPEWestern RegionalMeeting, Bakersfield, California, 30 March–1 April. SPE-24064-MS. https://doi.org/10.2118/24064-MS.
Lawrence, S. C., Kalenchuk, A. C., Ranicar, K. et al. 2009. Volatile-Phosphorous-Free Gellants for Hydrocarbon-based Fracturing Systems. SPE Prod & Oper 24 (4): 556–561. SPE-115481-PA. https://doi.org/10.2118/115481-PA.
LeBlanc, D., Martel, T., Graves, D. et al. 2011. Application of Propane (LPG) Based Hydraulic Fracturing in the McCully Gas Field, New Brunswick, Canada. Presented at the North American Unconventional Gas Conference and Exhibition, The Woodlands, Texas, 14–16 June. SPE-144093-MS. https://doi.org/10.2118/144093-MS.
Li, L., Lin, L., Bustos, O. et al. 2011. Method to Decrease Viscosity of Gelled Oil. US Patent Application No. 20110237470.
Lo, S., Miller, M. J., and Li, J. 2002. Encapsulated Breaker Release Rate at Hydrostatic Pressure and Elevated Temperatures. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 29 September–2 October. SPE-77744-MS. https://doi.org/10.2118/77744-MS.
Loree, D. N. and Mesher, S. T. 2014. Liquified Petroleum Gas Fracturing System. US Patent No. 8,689,876.
Lynn, J. D. and Nasr-El-Din, H. A. 2001. A Core Based Comparison of the Reaction Characteristics of Emulsified and In-Situ Gelled Acids in Low Permeability, High Temperature, Gas Bearing Carbonates. Presented at the SPE International Symposium on Oilfield Chemistry, Houston, 13–16 February. SPE-65386-MS. https://doi.org/10.2118/65386-MS.
Maberry, L. J., McConnell, S. B., Tanner, K. V. et al. 1998. Chemistry and Field Application of an Improved Continuous-Mix Gelled Oil. SPE Prod & Fac 13 (4): 236–242. SPE-52392-PA. https://doi.org/10.2118/52392-PA.
Malone, M. R. 2001. Fracturing with Crosslinked Methanol in Water-Sensitive Formations. Presented at the Permian Basin Oil and Gas Recovery Conference, Midland, Texas, 15–16 May. SPE-70009-MS. https://doi.org/10.2118/70009-MS.
Manalastas, P. V., Drake, E. N., Kresge, E. N. et al. 1992. Breaker Chemical Encapsulated with a Crosslinked Elastomer Coating. US Patent No. 5,110,486.
McDougall, L. A., Newlove, J. C., Manalastas, P. V. et al. 1993. Composition Comprising Polymer Encapsulant for Sealing Layer Encapsulated Substrate. US Patent No. 5,204,183.
McKenzie, L. F. 1980. Hydrocarbon Gels of Alumino Alkyl Acid Orthophosphates. Presented at SPE Oilfield and Geothermal Chemistry Symposium, Stanford, California, 28–30 May. SPE-9007-MS. https://doi.org/10.2118/9007-MS.
Mesmer, R. E., Baes, C. F., and Sweeton, F. H. 1972. Acidity Measurements at Elevated Temperatures: VI. Boric Acid Equilibria. Inorg. Chem. 11 (3): 537–543. https://doi.org/10.1021/ic50109a023.
Metcalf, S., Lopez, H., Hoff, C. et al. 2000. Gas Production from Low Permeability Carbonates Enhanced Through Usage of a New Acid Polymer System. Presented at the SPE/CERI Gas Technology Symposium, Calgary, 3–5 April. SPE-59756-MS. https://doi.org/10.2118/59756-MS.
Mirakyan, A., Hutchins, R., and Makarychev-Mikhailov, S. 2015. Parylene Coated Chemical Entities for Downhole Treatment Applications. US Patent Application No. 20,150,114,648.
Montgomery, C. 2013. Fracturing Fluids Components. In Effective and Sustainable Hydraulic Fracturing, ed. A. P. Bunger, J. McLennan, and R. Jeffrey, Chap. 2, 25–45. Rijeka, Croatia: InTechOpen.
Montgomery, C. T. and Smith, M. B. 2010. Hydraulic Fracturing: History of an Enduring Technology. J Pet Technol 62 (12): 26–32. SPE-1210-0026-JPT. https://doi.org/10.2118/1210-0026-JPT.
Muir, D. J. and Irwin, M. J. 2000. Encapsulated Breakers, Compositions and Methods of Use. US Patent No. 6,162,766.
Muthusamy, R., Patil, P. R., and Pandya, N. A. 2014. Controlled Release Breaker Composition for Oil Field Applications. US Patent No. 8,695,704.
Newlove, J. C., Jones, C. K., and Malekahmadi, F. 1999. Use of Breaker Chemicals in Gelled Hydrocarbons. US Patent No. 5,948,735.
Nolte, K. G. 1985. Fracturing Fluid Breaker System Which Is Activated by Fracture Closure. US Patent No. 4,506,734.
Norman, L., Vitthal, S., and Terracina, J. 1995. New Breaker Technology for Fracturing High-Permeability Formations. Presented at the SPE European Formation Damage Conference, The Hague, 15–16 May. SPE-30097-MS. https://doi.org/10.2118/30097-MS.
Norman, L. R., and Laramay, S. B. 1994. Encapsulated Breakers and Method for Use in Treating Subterranean Formations. US Patent No. 5,373,901.
Norman, L. R., Turton, R., and Bhatia, A. L. 2001. Breaking Fracturing Fluid in Subterranean Formation. European Patent Application No. 1,152,121.
Ocampo, A. M. 2009. Persulfate Activation by Organic Compounds. PhD dissertation, Washington State University, Pullman, Washington.
Omari, A., Chauveteau, G., and Tabary, R. 2003. Gelation of Polymer Solutions under Shear Flow. Colloid. Surface. A 225 (1–3): 37–48. https://doi.org/10.1016/S0927-7757(03)00319-4.
Parker, M. A. and Laramay, S. B. 1992. Properties and Application of Delayed-Release Breakers. Presented at the SPE Mid-Continent Gas Symposium, Amarillo, Texas, 13–14 April. SPE-24300-MS. https://doi.org/10.2118/24300-MS.
Patil, P., Muthusamy, R., and Pandya, N. 2013. Novel Controlled-Release Breakers for High-Temperature Fracturing. Presented at the North Africa Technical Conference and Exhibition, Cairo, 15–17 April. SPE-164656-MS. https://doi.org/10.2118/164656-MS.
Perfetto, R., Melo, R. C. B., Martocchia, F. et al. 2013. Oil-Based Fracturing Fluid: First Results in West Africa Onshore. Presented at the International Petroleum Technology Conference, Beijing, 26–28 March. IPTC-16640-MS. https://doi.org/10.2523/IPTC-16640-MS.
Rahim, Z., Al-Anazi, H., and Al-Kanaan, A. 2013. Selecting Optimal Fracture Fluids, Breaker System, and Proppant Type for Successful Hydraulic Fracturing and Enhanced Gas Production—Case Studies. Presented at the SPE Unconventional Gas Conference and Exhibition, Muscat, Oman, 28–30 January. SPE-163976-MS. https://doi.org/10.2118/163976-MS.
Reddy, B. R. 2013. Laboratory Characterization of Gel Filter Cake and Development of Nonoxidizing Gel Breakers for Zirconium-Crosslinked Fracturing Fluids. SPE J. 19 (4): 662–673. SPE-164116-PA. https://doi.org/10.2118/164116-PA.
Rickards, A. R., Tjon-Joe-Pin, R. M., and Boles, J. L. 1993. Enzymatic Breaker System for Nondamaging Removal of Cellulous-Based Blocking Gels. Presented at the SPE Production Operations Symposium, Oklahoma City, Oklahoma, 21–23 March. SPE-25488-MS. https://doi.org/10.2118/25488-MS.
Rietjens, M. and Steenbergen, P. A. 2005. Crosslinking Mechanism of Boric Acid with Diol Revisited. Eur. J. Inorg. Chem. 2005 (6): 1162–1174. https://doi.org/10.1002/ejic.200400674.
Ritter, S. K. 2014. A New Way of Fracking. Chemical & Engineering News 92 (19): 31–33.
Rose, J., De Bruin, T. J. M., Chauveteau, G. et al. 2003. Aqueous Zirconium Complexes for Gelling Polymers. A Combined X-ray Absorption Spectroscopy and Quantum Mechanical Study. J. Phys. Chem. B 107 (13): 2910–2920. https://doi.org/10.1021/jp027114c.
Rose, J., Moulin, I., Masion, A. et al. 2001. X-ray Absorption Spectroscopy Study of Immobilization Processes for Heavy Metals in Calcium Silicate Hydrates. 2. Zinc. Langmuir 17 (12): 3658–3665. https://doi.org/10.1021/la001302h.
Sarwar, M. U., Cawiezel, K. E., and Nasr-El-Din, H. A. 2011. Gel Degradation Studies of Oxidative and Enzyme Breakers to Optimize Breaker Type and Concentration for Effective Break Profiles at Low and Medium Temperature Ranges. Presented at the SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, 24–26 January. SPE-140520-MS. https://doi.org/10.2118/140520-MS.
Sinton, S. W. 1987. Complexation Chemistry of Sodium Borate with Poly(vinyl alcohol) and Small Diols. A 11B NMR Study. Macromolecules 20 (10): 2430–2441. https://doi.org/10.1021/ma00176a018.
Small, J., Wallace, M., Van Howe, S. et al. 1991. Improving Fracture Conductivities with a Delayed Breaker System: A Case History. Presented at the SPE Gas Technology Symposium, Houston, 23–25 January. SPE-21497-MS. https://doi.org/10.2118/21497-MS.
Smith, C. F. 1973. Gas Well Fracturing Using Gelled Non-Aqueous Fluids. Presented at the Fall Meeting of the Society of Petroleum Engineers of AIME, Las Vegas, Nevada, 30 September–3 October. SPE-4678-MS. https://doi.org/10.2118/4678-MS.
Smith, K. W. and Persinski, L. J. 1995. Hydrocarbon Gels Useful in Formation Fracturing. US Patent No. 5,417,287.
Sun, H., Wood, B., Stevens, R. F. et al. 2011. A Nondamaging Friction Reducer for Slickwater Frac Applications. Presented at the SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, 24–26 January. SPE-139480-MS. https://doi.org/10.2118/139480-MS.
Taylor, K. C. and Nasr-El-Din, H. A. 2002. Coreflood Evaluation of In-Situ Gelled Acids. Presented at the International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, 20–21 February. SPE-73707-MS. https://doi.org/10.2118/73707-MS.
Taylor, R. S., Stempler, P. S., Lemieux, A. et al. 2006. Prevention of Refinery Plugging by Residual Oil Gellant Chemicals in Crude-Optimization of Phosphonate Ester Oil Gellants. J Can Pet Technol 45 (5): 16–20. PETSOC-06-05-TN1. https://doi.org/10.2118/06-05-TN1.
Tudor, E. H., Allen, S., and Pike, B. 2009. 100% Gelled LPG Fracturing Process: An Alternative to Conventional Water-Based Fracturing Techniques. Presented at the SPE Eastern Regional Meeting, Charleston, West Virginia, 23–25 September. SPE-124495-MS. https://doi.org/10.2118/124495-MS.
Vezza, M., Martin, M., Thompson, J. E. et al. 2001. Morrow Production Enhanced by New, Foamed, Oil-Based Gel Fracturing Fluid Technology. Presented at the SPE Production and Operations Symposium, Oklahoma City, Oklahoma, 24–27 March. SPE-67209-MS. https://doi.org/10.2118/67209-MS.
Walles, W. E., Williamson, T. D. and Tomkinson, D. L. 1988. Method for Treating Subterranean Formations. US Patent No. 4,741,401.
Woo, G. T., Lopez, H., Metcalf, A. S. et al. 1999. A New Gelling System for Acid Fracturing. Presented at the SPE Mid-Continent Operations Symposium, Oklahoma City, Oklahoma, 28–31 March. SPE-52169-MS. https://doi.org/10.2118/52169-MS.
Yeager, V. and Shuchart, C. 1997. In-Situ Gels Improve Formation Acidizing. Oil & Gas Journal 95 (3): 70–72.
Zhang, B., Huston, A., Whipple, L. et al. 2013. A Superior, High-Performance Enzyme for Breaking Borate Crosslinked Fracturing Fluids Under Extreme Well Conditions. SPE Prod & Oper 28 (2): 210–216. SPE-160033-PA. https://doi.org/10.2118/160033-PA.
Zuo, M., Liu, T., Han, J. et al. 2014. Preparation and Characterization of Microcapsules Containing Ammonium Persulfate as Core by In Situ Polymerization. Chem. Eng. J. 249 (1 August): 27–33. https://doi.org/10.1016/j.cej.2014.03.041.