Laboratory Studies of Fracture Geometry in Multistage Hydraulic Fracturing Under Triaxial Stresses

Abstract Field evidence of production logs after fracturing have documented the existence of abundant natural fractures in Weiyuan shale plays, which is widely acknowledged to have a positive impact on fracture network complexity. On the other hand, cases of severe casing failures have been frequently reported in this field during multistage fracturing jobs. Stress interference between two adjacent stages may intensify non-uniform loading on the casing string and accommodate failure. To better understand this problem, we establish a coupled 3D reservoir-scale model with complex well trajectory and tie it to a single well-scale model consisting of casing and the surrounding cement sheath. Using this model, we investigate the potential impacts of cement deficiency, clustered perforations, fracture geometry as well as spacing strategy on casing integrity. Our simulation results indicate that cement deficiency could intensify the load nonuniformity around the borehole which escalates the potential threats for casing failure. When cement deficiency reaches 45° along the minimum horizontal stress, it has the largest influence on the stress level in the casing. In addition, perforations could lower the casing strength, but the reduction may not change furthermore when the perforation diameter reaches a certain value. Moreover, impacts of fracture geometry and spacing on casing deformation are investigated. We conclude that the lower ratio of fracture length to its width and reasonable spacing strategy could help reduce the load non-uniformity on casing which avoid the casing deformation. The described workflow may be adopted in other areas to predict the possible casing failure problems induced by multistage hydraulic fracturing with cheap computational costs, to anticipate the challenges and avoid them by revisiting pumping schedule or spacing strategy.

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Novel Coiled Tubing Perforation Approach Enables Efficient Multistage Hydraulic Fracturing Operations in a Horizontal Well in Oman

10.2523/18735-ms ◽

2016 ◽

Author(s):

Ali Al-Ghaithi ◽

Fahad Alawi ◽

Ernest Sayapov ◽

Ehab Ibrahim ◽

Najet Aouchar ◽

...

Keyword(s):

Hydraulic Fracturing ◽

Horizontal Well ◽

Multistage Hydraulic Fracturing ◽

Coiled Tubing

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Stress perturbation caused by multistage hydraulic fracturing: Implications for deep fault reactivation

International Journal of Rock Mechanics and Mining Sciences ◽

10.1016/j.ijrmms.2021.104704 ◽

2021 ◽

Vol 141 ◽

pp. 104704

Author(s):

Mengke An ◽

Fengshou Zhang ◽

Egor Dontsov ◽

Derek Elsworth ◽

Hehua Zhu ◽

...

Keyword(s):

Hydraulic Fracturing ◽

Fault Reactivation ◽

Deep Fault ◽

Multistage Hydraulic Fracturing

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Evolution and management of thick-hard roof using goaf-based multistage hydraulic fracturing technology—a case study in western Chinese coal field

Arabian Journal of Geosciences ◽

10.1007/s12517-021-07111-5 ◽

2021 ◽

Vol 14 (10) ◽

Author(s):

KaigeZheng ◽

Tong Zhang ◽

Jizhan Zhao ◽

Yu Liu ◽

Fei Yu

Keyword(s):

Hydraulic Fracturing ◽

Coal Field ◽

Hard Roof ◽

Multistage Hydraulic Fracturing ◽

Chinese Coal

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Increasing the Productivity of Horizontal Wells Through Multistage Hydraulic Fracturing Using a Working Fluid Based on a New Biopolymer System

10.2118/206655-ms ◽

2021 ◽

Author(s):

Nikolay Mikhaylovich Migunov ◽

Aleksey Dmitrievich Alekseev ◽

Dinar Farvarovich Bukharov ◽

Vadim Alexeevich Kuznetsov ◽

Aleksandr Yuryevich Milkov ◽

...

Keyword(s):

Hydraulic Fracturing ◽

Russian Federation ◽

Oil Production ◽

Horizontal Wells ◽

Working Fluid ◽

High Tech ◽

Executive Order ◽

Bazhenov Formation ◽

Multistage Hydraulic Fracturing ◽

The Russian Federation

Abstract According to the US Energy Agency (EIA), Russia is the world leader in terms of the volume of technically recoverable "tight oil" resources (U.S. Department of Energy, 2013). To convert them into commercial production, it is necessary to create cost-effective development technologies. For this purpose, a strategy has been adopted, which is implemented at the state level and one of the key elements of which is the development of the high-tech service market. In 2017, the Minister of Energy of the Russian Federation, in accordance with a government executive order (Government Executive Order of the Russian Federation, 2014), awarded the Gazprom Neft project on the creation of a complex of domestic technologies and high-tech equipment for developing the Bazhenov formation with the national status. It is implemented in several directions and covers a wide range of technologies required for the horizontal wells drilling and stimulating flows from them using multi-stage hydraulic fracturing (MS HF) methods. Within the framework of the technological experiment implemented at the Palyanovskaya area at the Krasnoleninskoye field by the Industrial Integration Center "Gazpromneft - Technological Partnerships" (a subsidiary of Gazprom Neft), from 2015 to 2020, 29 high-tech wells with different lengths of horizontal wellbore were constructed, and multistage hydraulic fracturing operations were performed with various designs. Upon results of 2020, it became possible to increase annual oil production from the Bazhenov formation by 78 % in comparison with up to 100,000 tons in 2019. The advancing of development technologies allowed the enterprise to decrease for more than twice the cost of the Bazhenov oil production from 30 thousand rubles per ton (69$/bbl) at the start of the project in 2015 to 13 thousand rubles (24$/bbl) in 2020. A significant contribution to the increase in production in 2020 was made by horizontal wells, where MS HF operations were carried out using an experimental process fluid, which is based on the modified Si Bioxan biopolymer. This article is devoted to the background of this experiment and the analysis of its results.

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