Key problems and solutions in supercritical CO₂ fracturing technology

Abstract

Supercritical CO₂ fracturing is considered to be a new method for efficient exploitation of unconventional reservoirs, such as shale gas, coal bed methane, and tight sand stone gas. Supercritical CO₂ has many special properties including low viscosity, high diffusion coefficient, and lack of surface tension, which brings about great advantages for fracturing. However, these properties also cause several problems, such as difficulty in proppant transportation, high friction loss, and high pump displacement. In this paper, the above problems were analyzed by combining field test with laboratory study and specific solutions to these problems are given. The high frictionloss in the pipeline could be reduced by developing a new drag reducing agent and selecting large-size casing. Besides, for the problem of poor capacity in proppant carrying and sand plug, the methods of adding tackifier into supercritical CO₂, increasing pump displacement and selecting ultra-low density proppants are proposed. Moreover, for the problem of fast leak-off and high requirement for pump displacement, the displacement can be increased or the pad fluid can be injected into the reservoir. After solving the above three problems, the field test of supercritical CO₂ fracturing can be conducted. The research results can promote the industrialization process of supercritical CO₂ fracturing.

Keywords

supercritical CO₂ / fracturing / friction loss / proppant carrying / flied test problem

References

[1] Wang H, Li G, Shen Z. A feasibility analysis on shale gas exploitation with supercritical carbon dioxide. Energy Source Part A, 2012, 34(15): 1426–1435

[2] Wang H, Shen Z, Li G, Shale gas exploitation with supercritical CO₂ technology. Engineering and Science, 2012, 10(4): 13–17

[3] Li G, Wang H, Shen Z, Application investigations and prospects of supercritical carbon dioxide jet in petroleum engineering. Journal of China University of Petroleum (Edition of Natural Science), 2013, 37(5): 76–80 (in Chinese)

[4] Li G, Wang H, Shen Z, Supercritical CO₂ jet fracturing with coiled tubing. Technical Report ZL201110078618.6. 2011 (in Chinese)

[5] Liu H, Wang F, Zhang J, Fracturing with carbon dioxide: application status and development trend. Petroleum Exploration and Development, 2014, 41(4): 513–519

[6] Wang Z, Sun B, Sun X, Phase state variations for supercritical carbon dioxide drilling. Greenhouse Gases, Science and Technology, 2016, 6(1): 83–93

[7] Ni H, Song W, Wang R, Coupling model for carbon dioxide wellbore flow and heat transfer in coiled tubing drilling. Journal of Natural Gas Science and Engineering, 2016, 30: 414–420

[8] Hu Y, Liu Y, Cai C, Fracture initiation of an inhomogeneous shale rock under a pressurized supercritical CO₂ jet. Applied Sciences (Basel, Switzerland), 2017, 7(10): 1093

[9] Wang H, Li L, He Z, The expulsive force of the development of CO₂ sequestration- application of SC-CO₂ fluid in oil and gas extraction. Frontiers in Energy, 2019, 13(1): 1–8

[10] Cheng Y, Li G, Wang H, Pressure boosting effect in perforation cavity during supercritical carbon dioxide jet fracturing. Atomization and Sprays, 2013, 23(5): 463–474

[11] Hou L, Jiang T, Liu H, An evaluation method of supercritical CO₂ thickening result for particle transporting. Journal of CO₂ Utilization, 2017, 21: 247–252

[12] Li G, Wang H, Shen Z, Experimental study on the efficiency of cuttings carrying with supercritical CO₂. In: IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition, Tianjin, China, 2012

[13] Feng Y, Gray K E. Modeling lost circulation through drilling-induced fractures. SPE Journal, 2018, 23(1): 1–19

[14] Li X, Li G, Yu W, Thermal effects of liquid-supercritical CO₂ arising from fluid expansion in fracturing. SPE Journal, 2018, 23(6): 1–15

[15] Li X, Li G, Sepehrnoori K, Estimation and analysis of CO₂ friction loss in wellbore during liquid-supercritical CO₂ fracturing. SPE Production & Operations, 2019, 34(1): 1–16

[16] Li X, Li G, Wang G, A unified model for wellbore flow and heat transfer in pure CO₂ injection for geological sequestration, EOR and fracturing operations. International Journal of Greenhouse Gas Control, 2017, 57: 102–115

[17] Wang H, Shen Z, Li G. Wellbore flow model of coiled tubing drilling with supercritical carbon dioxide. Energy Sources: Part A, 2012, 34(14):1347–1362

[18] Liu L, Zhu W, Wei C, Microcrack-based geomechanical modeling of rock-gas interaction during supercritical CO₂ fracturing. Journal of Petroleum Science Engineering, 2018, 164: 91–102

[19] Wang J, Sun B, Wang Z, Study on filtration patterns of supercritical CO₂ fracturing in unconventional natural gas reservoirs. Greenhouse Gas Science and Technology, 2017, 7(6): 1126–1140

[20] Liu S, Wang J, He H, Mechanism on imbibition of fracturing fluid in nanopore. Nanoscience and Nanotechnology Letters, 2018, 10(1): 87–93

[21] Feng Y, Li X, Gray K E. Development of a 3D numerical model for quantifying fluid-driven interface debonding of an injector well. International Journal of Greenhouse Gas Control, 2017, 62: 76–90

[22] Wang X, Wu J, Zhang J. Application of CO₂ fracturing technology for terrestrial shale gas reservoirs. Natural Gas Industry, 2014, 34(1): 64–67 (in Chinese)

[23] Song Z, Su W, Yang Y, Experimental studies of CO₂/sand dry-frac process. Natural Gas Industry, 2014, 34(6): 55–59 (in Chinese)

[24] Huo H, Wang H, Ni H, Study of critical annulus up-returning velocity of cuttings carried by supercritical CO₂ in deviated well. Journal of CO₂ Utilization, 2017, 20: 105–112

[25] Sun B, Sun W. Research progress and prospective of supercritical CO₂ thickening technology. Journal of China University of Petroleum (Edition of Natural Science), 2015 (3): 76–83 (in Chinese)

[26] Yin H, Zhou J, Xian X, Experimental study of the effects of sub- and super-critical CO₂ saturation on the mechanical characteristics of organic-rich shales. Energy, 2017, 132: 84–95

[27] Zhang X, Lu Y, Tang J, Zhou Z, Experimental study on fracture initiation and propagation in shale using supercritical carbon dioxide fracturing. Fuel, 2017, 190(15): 370–378

[28] Rui Z, Wang X, Zhang Z, A realistic and integrated model for evaluating oil sands development with steam assisted gravity drainage technology in Canada. Applied Energy, 2018, 213: 76–91

[29] Ao X, Lu Y Y, Tang J R, Investigation on the physics structure and chemical properties of the shale treated by supercritical CO₂. Journal of CO₂ Utilization, 2017, 20:74–281

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature