Micromechanical analysis of hydraulic fracturing in the toughness-dominated regime: implications to supercritical carbon dioxide fracturing

2019 ◽  
Vol 24 (5) ◽  
pp. 1815-1831 ◽  
Author(s):  
Mengli Li ◽  
Fengshou Zhang ◽  
Li Zhuang ◽  
Xi Zhang ◽  
Pathegama Ranjith
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Hydraulic Fracturing ◽  
Micromechanical Analysis ◽  
Supercritical Carbon

Thermal Effects of Liquid/Supercritical Carbon Dioxide Arising From Fluid Expansion in Fracturing

SPE Journal ◽  
2018 ◽  
Vol 23 (06) ◽  
pp. 2026-2040 ◽  
Author(s):  
Xiaojiang Li ◽  
Gensheng Li ◽  
Wei Yu ◽  
Haizhu Wang ◽  
Kamy Sepehrnoori ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Thermal Stress ◽  
Supercritical Carbon Dioxide ◽  
Hydraulic Fracturing ◽  
Thermal Effect ◽  
Fracture Propagation ◽  
Fracture Initiation ◽  
Thermodynamic Behavior ◽  
Fracture Complexity ◽  
Supercritical Carbon

Summary Liquid/supercritical carbon dioxide (L/SC-CO2) fracturing is an emerging technology for shale gas development because it can effectively overcome problems related to clay swelling and water scarcity. Recent applications show that L/SC-CO2 fracturing can induce variations in temperature. Understanding of this phenomenon is rudimentary and needs to be carefully addressed to improve the understanding of CO2 thermodynamic behavior, and thus helps to optimize CO2 fracturing in the field. In this paper, we develop a numerical model to assess the impact of thermal effect on fracture initiation during CO2 fracturing. The model couples fluid flow and heat transfer in the fracture, and is verified by a peer-reviewed solution and observation in laboratory experiments. The velocity, pressure, and temperature are calculated at various time to demonstrate the thermodynamic behavior during fracture initiation. A pseudo shock wave is observed, associated with a compression wave and an expansion wave, which finally leads to an increase in temperature in the new fracture and a decrease in temperature in the initial fracture. The thermal stress is derived to investigate the difference between hydraulic fracturing and CO2 fracturing. The results show that thermal stress, resulting from CO2 fracturing initiation, is comparable to the rock strength, which will help induce microfractures, and thus promote the fracture complexity. The formation pressure after CO2 fracturing is also calculated to evaluate the pressure-buildup potential. This work highlights the importance of CO2 expansion during and after fracturing. It is one of the unique features that differs from hydraulic fracturing. For field-design recommendations, to enhance the thermal effect of CO2 fracturing, it is a good strategy to pump CO2 at high pressure and low temperature into the reservoirs with high Young's modulus, low Poisson's ratio, low permeability, and high geothermal temperature (or large depth). This paper does not address the dynamics of fracture propagation under the influence of thermal effect. Rather, it intends to demonstrate the potential of the thermal effect of CO2 fluid in assisting the fracture propagation, and the importance of incorporating the compressibility of CO2 into fracture modeling and operation design. Failing to account for this thermal effect might underestimate the fracture complexity and stimulated reservoir volume.

scholarly journals The role of supercritical carbon dioxide for recovery of shale gas and sequestration in gas shale reservoirs

2021 ◽  
Author(s):  
Qiao Lyu ◽  
Jingqiang Tan ◽  
Lei Li ◽  
Yiwen Ju ◽  
Andreas Busch ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Hydraulic Fracturing ◽  
Shale Gas ◽  
Environmental Issues ◽  
Gas Shale ◽  
Horizontal Drilling ◽  
Shale Reservoirs ◽  
Supercritical Carbon

The development of hydraulic fracturing and horizontal drilling techniques has promoted the exploitation of shale gas resources. However, using water has several potential drawbacks including environmental issues, e.g., the contamination...

scholarly journals Numerical Simulation of Fracturing in Coals Using Water and Supercritical Carbon Dioxide with Potential-Based Cohesive Zone Models

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jianfeng Yang ◽  
Yuqing Ren ◽  
Dingding Zhang ◽  
Yongliang Liu ◽  
Zhe Ma
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Crack Initiation ◽  
Hydraulic Fracturing ◽  
Cohesive Zone ◽  
Mode I ◽  
Zone Model ◽  
Cohesive Elements ◽  
Secondary Cracks ◽  
Supercritical Carbon

The Park-Paulino-Roesler (PPR) cohesive zone model (CZM) for coal was established for analyzing mixed-mode I/II fractures using semicircular specimens under punch-through shear (PTS) and three-point bending (SCB) tests. In these methods, the main parameters of the fracture were obtained through SCB tests and PTS tests. And according to the experimental results, the coal specimens show obvious characteristics of ductile fracture under mode I and II loading. Moreover, hydraulic and supercritical carbon dioxide (ScCO2) fracture tests were conducted, and accordingly, it was found that the crack initiation pressure of coal specimens for hydraulic fracturing is 17.76 MPa, about 1.59 times that driven by ScCO2. And the crack initiation time of coal with ScCO2 fracturing is 123.73 s, which is 1.58 times that for hydraulic fracturing. A macrocrack eventually formed in the coal specimen due to the hydraulic drive, which penetrated through the entire specimen. Yet, there was no crack penetrating the whole fracture specimen and several widely distributed secondary cracks in the fractured coal specimens by ScCO2. Furthermore, zero-thickness pore pressure cohesive elements were utilized to investigate multicrack propagation in coals undergoing hydraulic and ScCO2 fracturing. The constitutive relationships of the established PPR CZM were introduced into the cohesive elements. The obtained results are consistent with the hydraulic and ScCO2 fracturing experiment results for the coal specimens. This indicates that the established PPR CZMs can accurately represent the crack propagation behavior in coals for hydraulic and ScCO2 fracturing.

The decellularization of allografts with supercritical carbon dioxide and detergents. Experimental data

2019 ◽  
Vol 20 (5) ◽  
pp. 402-409 ◽  
Author(s):  
D.V. Britikov ◽  
I.S. Chashchin ◽  
G.A. Khugaev ◽  
N.P. Bakuleva
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Carbon
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