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A Comparison of Shale Gas Fracturing Based on Deep and Shallow Shale Reservoirs in the United States and China
Qixing Zhang1,2, Bing Hou1,2,*, Huiwen Pang1,2, Shan Liu1,2, Yue Zeng1,2
1
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing, 102249, China
2
Key Laboratory of Petroleum Engineering, Ministry of Education, China University of Petroleum (Beijing), Beijing, 102249, China
* Corresponding Author: Bing Hou. Email:
Computer Modeling in Engineering & Sciences 2022, 133(3), 471-507. https://doi.org/10.32604/cmes.2022.020831
Received 15 December 2021; Accepted 27 March 2022; Issue published 03 August 2022
Abstract
China began to build its national shale gas demonstration area in 2012. The central exploration, drilling, and
development technologies for medium and shallow marine shale reservoirs with less than 3,500 m of buried depth
in Changning-Weiyuan, Zhaotong, and other regions had matured. In this study, we macroscopically investigated
the development history of shale gas in the United States and China and compared the physical and mechanical
conditions of deep and shallow reservoirs. The comparative results revealed that the main reasons for the order-ofmagnitude difference between China’s annual shale gas output and the United States could be attributed to three
aspects: reservoir buried depth, reservoir physical and mechanical properties, and engineering technology level.
The current engineering technology level of China could not meet the requirements of increasing production and
reducing costs for deep shale gas reservoirs; they had reached the beneficial threshold development stage and lacked
the capacity for large-scale commercial production. We identified several physical and mechanical reasons for this
threshold development stage. Deep shale reservoirs were affected by the bedding fracture, low brittleness index, low
clay mineral content, and significant areal differences, as well as by the transformation from elasticity to plasticity,
difficulty in sanding, and high mechanical and strength parameters. Simultaneously, they were accompanied by
six high values of formation temperature, horizontal principal stress difference, pore pressure, fracture pressure,
extension pressure, and closure pressure. The key to deep shale gas horizontal well fracturing was to improve the
complexity of the hydraulic fracture network, form adequate proppant support of fracture surface, and increase the
practical stimulated reservoir volume (SRV), which accompanied visual hydraulic discrete network monitoring.
On this basis, we proposed several ideas to improve China’s deep shale gas development involving advanced
technology systems, developing tools, and supporting technologies in shale gas exploration and development in
the United States. These ideas primarily involved stimulation technologies, such as vertically integrated dessert
identification and optimization, horizontal well multistage/multicluster fracturing, staged tools development for
horizontal wells, fractures network morphology monitoring by microseismic and distributed optical fiber, shale
hydration expansion, soak well, and fracturing fluid flow back. China initially developed the critical technology
of horizontal well large-scale and high-strength volume fracturing with a core of “staged fracturing with dense
cutting + shorter cluster spacing + fracture reorientation by pitching + forced-sand addition + increasing diameter
perforating + proppant combination by high strength and small particle size particles”. We concluded that China
should continue to conduct critical research on theories and technical methods of horizontal well fracturing,
suitable for domestic deep and ultra-deep marine and marine-continental sedimentary shale, to support and
promote the efficient development of shale gas in China in the future. It is essential to balance the relationship
between the overall utilization degree of the gas reservoir and associated economic benefits and to localize some essential tools and supporting technologies. These findings can contribute to the flourishing developments of
China’s deep shale gas.
Keywords
Cite This Article
Zhang, Q., Hou, B., Pang, H., Liu, S., Zeng, Y. (2022). A Comparison of Shale Gas Fracturing Based on Deep and Shallow Shale Reservoirs in the United States and China.
CMES-Computer Modeling in Engineering & Sciences, 133(3), 471–507. https://doi.org/10.32604/cmes.2022.020831