scholarly journals Pressurization Rate Effect on Breakdown Pressure of Hydraulic Fracturing. Hydraulic fracturing experiment in granitic rock with scarce joints in China (1st Report).

1996 ◽  
Vol 112 (9) ◽  
pp. 595-600
Author(s):  
Koichi SHIN ◽  
Bo-chong ZHANG ◽  
Fangquan LI ◽  
Tadashi KANAGAWA ◽  
Seisuke OKUBO
Keyword(s):  
Hydraulic Fracturing ◽  
Granitic Rock ◽  
Rate Effect ◽  
Breakdown Pressure ◽  
Pressurization Rate

The effect of stress on the primary permeability of rock cores—a facet of hydraulic fracturing

1981 ◽  
Vol 18 (2) ◽  
pp. 195-204 ◽  
Author(s):  
R. Heystee ◽  
J.-C. Roegiers
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
The State ◽  
Stress Conditions ◽  
Breakdown Pressure ◽  
Rock Types ◽  
State Of Stress ◽  
Pressurization Rate ◽  
Fluid Penetration ◽  
Fracturing Experiments

Recent laboratory hydraulic fracturing experiments have shown that fluid penetration into the rock mass adjacent to the borehole being pressurized has a significant influence on the magnitude of the breakdown pressure. One factor affecting the degree of penetration of the pressurizing fluid is the permeability of the rock mass, which in turn is a function of the state of stress present in the rock mass. To study this permeability–stress relationship, a radial permeameter was constructed and three rock types tested. Derived expressions show that during radially divergent and convergent flow in the permeameter, the state of stress in the rock specimen is tensile and compressive respectively. The radial permeameter test results show that the permeability of rock increases significantly under tensile stress conditions and reduces under compressive stress conditions. The results from this study were used to develop a conceptual model which explains the dependency of breakdown pressure levels on the pressurization rate.

An Environment Friendly Approach to Reduce the Breakdown Pressure of High Strength Unconventional Rocks by Cyclic Hydraulic Fracturing

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Zeeshan Tariq ◽  
Mohamed Mahmoud ◽  
Abdulazeez Abdulraheem ◽  
Dhafer Al-Shehri ◽  
Mobeen Murtaza
Keyword(s):  
Hydraulic Fracturing ◽  
High Strength ◽  
Progressive Increase ◽  
New Method ◽  
Hydraulic Fractures ◽  
Breakdown Pressure ◽  
Environment Friendly ◽  
Rock Types ◽  
Pressurization Rate ◽  
Tight Rocks

Abstract Unconventional hydrocarbon resources mostly found in highly stressed, overpressured, and deep formations, where the rock strength and integrity are very high. When fracturing these kinds of rocks, the hydraulic fracturing operation becomes much more challenging and difficult and in some cases reaches to the maximum pumping capacity limits without generating any fracture. This reduces the operational gap to optimally place the hydraulic fractures. Current stimulation methods to reduce the fracture pressures involvement with adverse environmental effects and high costs due to the entailment of water mixed with huge volumes of chemicals. In this study, a new environment friendly approach to reduce the breakdown pressure of the unconventional rock is presented. The new method incorporates the injection of chemical-free fracturing fluid in a series of cycles with a progressive increase of the pressurization rate in each cycle. This study is carried out on different cement blocks with varying petrophysical and mechanical properties to simulate real rock types. The results showed that the new method of cyclic fracturing can reduce the breakdown pressure to 24.6% in ultra-tight rocks, 19% in tight rocks, and 14.8% in medium- to low-permeability rocks. This reduction in breakdown pressure helped to overcome the operational challenges in the field and makes the fracturing operation much greener.

scholarly journals Relaxation damage control via fatigue-hydraulic fracturing in granitic rock as inferred from laboratory-, mine-, and field-scale experiments

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arno Zang ◽  
Günter Zimmermann ◽  
Hannes Hofmann ◽  
Peter Niemz ◽  
Kwang Yeom Kim ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Induced Seismicity ◽  
Granitic Rock ◽  
Damage Control ◽  
Fracture Pattern ◽  
Fluid Injection ◽  
Field Scale ◽  
Breakdown Pressure ◽  
Geothermal Heat ◽  
Constant Flow Rate

AbstractThe ability to control induced seismicity in energy technologies such as geothermal heat and shale gas is an important factor in improving the safety and reducing the seismic hazard of reservoirs. As fracture propagation can be unavoidable during energy extraction, we propose a new approach that optimises the radiated seismicity and hydraulic energy during fluid injection by using cyclic- and pulse-pumping schemes. We use data from laboratory-, mine-, and field-scale injection experiments performed in granitic rock and observe that both the seismic energy and the permeability-enhancement process strongly depend on the injection style and rock type. Replacing constant-flow-rate schemes with cyclic pulse injections with variable flow rates (1) lowers the breakdown pressure, (2) modifies the magnitude-frequency distribution of seismic events, and (3) has a fundamental impact on the resulting fracture pattern. The concept of fatigue hydraulic fracturing serves as a possible explanation for such rock behaviour by making use of depressurisation phases to relax crack-tip stresses. During hydraulic fatigue, a significant portion of the hydraulic energy is converted into rock damage and fracturing. This finding may have significant implications for managing the economic and physical risks posed to communities affected by fluid-injection-induced seismicity.

The Prediction of Wellhead Pressure of Hydraulic Fracturing

2013 ◽  
Vol 405-408 ◽  
pp. 3323-3327
Author(s):  
Feng Shen ◽  
Zhou Wu ◽  
Nan Wang ◽  
Yong Ming Li
Keyword(s):  
Hydraulic Fracturing ◽  
Influencing Factor ◽  
Case Analysis ◽  
Fluid Density ◽  
Interaction Theory ◽  
Breakdown Pressure ◽  
Two Phase ◽  
Wellhead Pressure ◽  
Computing Method ◽  
Calculation Software

The accurate prediction of wellhead pressure in process of hydraulic fracturing is a keypoint to guide the design and construction of the fracturing, and does help in choosing appropriate wellhead equipment and pipeline. This paper calculates the formation breakdown pressure by using a self-made formation stress calculation software, analyzes perforation friction and near-wellbore friction on the basis of Michael theory, eatablishes a model of wellbore friction through Darcy-Weisbach equation and the momentum interaction theory of two-phase flow, and according to the composition of wellhead pressure, makes calculation software which can also analyze the influencing factor of wellbore friction, such as delivery rate, pipe diameter, fracturing fluid density and proppant size. Finally, case analysis verifies the accuracy of the computing method.

Coal Mine Hydraulic Fracturing Underground Drainage Research and Engineering Application

2017 ◽  
Vol 863 ◽  
pp. 334-341
Author(s):  
Jun Hui Fu ◽  
Guang Cai Wen ◽  
Fu Jin Lin ◽  
Hai Tao Sun ◽  
Ri Fu Li ◽  
...  
Keyword(s):  
Stress State ◽  
Hydraulic Fracturing ◽  
Coal Mine ◽  
Engineering Application ◽  
Fracture Morphology ◽  
Plane Stress State ◽  
Theoretical Formula ◽  
Test Results ◽  
Breakdown Pressure ◽  
Elastic Mechanics

Using elastic mechanics and fracture mechanics, analyzing the coal seam hydraulic fracturing breakdown pressure, given its theoretical formula. According to hydraulic fracturing stress status, given the form of two typical hydraulic fracture morphology. Analyzing hydraulic fracturing highly elliptical shape. The displacement field in plane stress state is given, and the theoretical formula of fracturing radius of hydraulic fracturing is deduced. The fracturing technology of underground fracturing is presented, and the fracturing location and fracturing parameters are determined. In Sihe Coal Mine conducted fracturing test, the test results showed that: the average of drainage volume of fracturing hole improved 4.4 times compared with non-pressed-hole. The extraction compliance time is reduced by 38%. Roadway tunneling speed was improved by 15%. It can solve the problem of gas overrun in roadway excavation well, and has a good application and popularization value.

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