scholarly journals A full three‐dimensional fracture propagation model for supercritical carbon dioxide fracturing

2020 ◽  
Vol 8 (8) ◽  
pp. 2894-2906
Author(s):  
Yuting He ◽  
Zhaozhong Yang ◽  
Yanfang Jiang ◽  
Xiaogang Li ◽  
Yongqing Zhang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Three Dimensional ◽  
Fracture Propagation ◽  
Propagation Model ◽  
Supercritical Carbon

scholarly journals Supercritical carbon dioxide design strategies: from drug carriers to soft killers

2015 ◽  
Vol 373 (2057) ◽  
pp. 20150009 ◽  
Author(s):  
Ana Aguiar-Ricardo ◽  
Vasco D. B. Bonifácio ◽  
Teresa Casimiro ◽  
Vanessa G. Correia
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Three Dimensional ◽  
Polymeric Materials ◽  
Drug Carriers ◽  
Water Soluble ◽  
Materials Processing ◽  
Design Strategies ◽  
Simple Economic ◽  
Supercritical Carbon

The integrated use of supercritical carbon dioxide (scCO 2 ) and micro- and nanotechnologies has enabled new sustainable strategies for the manufacturing of new medications. ‘Green’ scCO 2 -based methodologies are well suited to improve either the synthesis or materials processing leading to the assembly of three-dimensional multifunctional constructs. By using scCO 2 either as C1 feedstock or as solvent, simple, economic, efficient and clean routes can be designed to synthesize materials with unique properties such as polyurea dendrimers and oxazoline-based polymers/oligomers. These new biocompatible, biodegradable and water-soluble polymeric materials can be engineered into multifunctional constructs with antimicrobial activity, targeting moieties, labelling units and/or efficiently loaded with therapeutics. This mini-review highlights the particular features exhibited by these materials resulting directly from the followed supercritical routes.

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.

Conformal Copper Coating of True Three-Dimensional Through-Holes Using Supercritical Carbon Dioxide

2012 ◽  
Vol 51 (5S) ◽  
pp. 05EA01 ◽  
Author(s):  
Mitsuhiro Watanabe ◽  
Yuto Takeuchi ◽  
Takahiro Ueno ◽  
Masahiro Matsubara ◽  
Eiichi Kondoh ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Three Dimensional ◽  
Copper Coating ◽  
Supercritical Carbon

scholarly journals SUPERCRITICAL FLUID TREATMENT OF THREE-DIMENSIONAL HYDROGEL MATRICES, COMPOSED OF CHITOSAN DERIVATIVES

2016 ◽  
Vol 18 (3) ◽  
pp. 85-93 ◽  
Author(s):  
P. S. Timashev ◽  
K. N. Bardakova ◽  
S. N. Churbanov ◽  
L. I. Krotova ◽  
A. M. Grigoriev ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Elastic Modulus ◽  
Supercritical Carbon Dioxide ◽  
Three Dimensional ◽  
Contact Angles ◽  
Salt Form ◽  
Degree Of Reaction ◽  
Base Form ◽  
Salt Forms ◽  
Supercritical Carbon

Aim.Controlled treatment of the physico-chemical and mechanical properties of a three-dimensional crosslinked matrix based on reactive chitosan.Materials and methods.The three-dimensional matrices were obtained using photosensitive composition based on allyl chitosan (5 wt%), poly(ethylene glycol) diacrylate (8 wt%) and the photoinitiator Irgacure 2959 (1 wt%) by laser stereolithography setting. The kinetic swelling curves were constructed for structures in the base and salt forms of chitosan using gravimetric method and the contact angles were measured using droplet spreading. The supercritical fl uid setting (40 °C, 12 MPa) was used to process matrices during 1.5 hours. Using nanohardness Piuma Nanoindenter we calculated values of Young’s modulus. The study of cytotoxicity was performed by direct contact with the culture of the NIH 3T3 mouse fi broblast cell line.Results.Architectonics of matrices fully repeats the program model. Matrices are uniform throughout and retain their shape after being transferred to the base form. Matrices compressed by 5% after treatment in supercritical carbon dioxide (scCO2 ). The elastic modulus of matrices after scCO2 treatment is 4 times higher than the original matrix. The kinetic swelling curves have similar form. In this case the maximum degree of swelling for matrices in base form is 2–2.5 times greater than that of matrices in salt form. There was a surface hydrophobization after the material was transferred to the base form: the contact angle is 94°, and for the salt form it is 66°. The basic form absorbs liquid approximately 1.6 times faster. The fi lm thickness was increased in the area of contact with the liquid droplets after absorption by 133 and 87% for the base and the salt forms, respectively. Treatment of samples in scCO2 reduces their cytotoxicity from 2 degree of reaction (initial samples) down to 1 degree of reaction.Conclusion.The use of supercritical carbon dioxide for scaffolds allows improving biocompatibility of the applied material for 1 degree and increasing the elastic modulus of the material more than 3 times. Allyl chitosan forms stable three-dimensional networks during laser photopolymerization. This enables desorbing toxic low molecular weight component without destruction of the matrix structure. 

Conformal Copper Coating of True Three-Dimensional Through-Holes Using Supercritical Carbon Dioxide

2012 ◽  
Vol 51 ◽  
pp. 05EA01 ◽  
Author(s):  
Mitsuhiro Watanabe ◽  
Yuto Takeuchi ◽  
Takahiro Ueno ◽  
Masahiro Matsubara ◽  
Eiichi Kondoh ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Three Dimensional ◽  
Copper Coating ◽  
Supercritical Carbon

scholarly journals Supercritical carbon dioxide as a tool for improving the biocompatible properties of biopolymer and tissue specific scaffolds for tissue engineering

2021 ◽  
Vol 23 (2) ◽  
pp. 104-113
Author(s):  
E. A. Nemets ◽  
A. E. Lazhko ◽  
A. M. Grigoryev ◽  
V. Yu. Belov ◽  
V. A. Surguchenko ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Flow Rate ◽  
Sodium Dodecyl ◽  
Three Dimensional ◽  
Copolymer Composition ◽  
Porcine Liver ◽  
Tissue Specific ◽  
Biopolymer Scaffolds ◽  
Supercritical Carbon

Objective: to investigate the efficacy of supercritical carbon dioxide (sc-CO2) for enhancштп the biocompatibility of biopolymer scaffolds from biodegradable materials and tissue-specific scaffolds from decellularized porcine liver slices (PLSs) or fine porcine cartilage particles (FPCPs).Materials and methods. Biopolymer scaffolds of a polyoxy(butyrate-co-valerate) and gelatin copolymer composition, 4 mm in diameter and 80 mm in length, were formed by electrospinning (NANON-01A, MECC CO, Japan) and stabilized by incubation in glutaraldehyde vapor for 48 hours at room temperature. For decellularization, PLSs and FPCPs were incubated under periodic stirring in buffer (pH = 7.4) solutions of sodium dodecyl sulfate (0.1%) and Triton X-100 with increasing concentrations (1, 2, and 3%). Treatment in a sc-CO2 atmosphere was done at 150–300 bar pressure, 35 °C temperature, and 0.25–2.5 mL/min flow rate of sc-CO2 for 8–24 hours. 10% ethanol was introduced as a polarity modifier. Cytotoxicity was studied according to GOST ISO 10993-5-2011. The growth of NIH/3T3 in the presence of samples was studied using an interactive optical system IncuCyte Zoom.Results. The effect of the sc-CO2 flow rate and pressure, and the effect of addition of ethanol, on the biocompatibility of scaffolds was investigated. It was found that treatment at a low sc-CO2 flow rate (0.25 mL/min) does not achieve the required cytotoxicity. Complete absence of cytotoxicity in biopolymer scaffolds was achieved in the presence of 10% ethanol, at a sc-CO2 flow rate of 2.5 mL/min, 300 bar pressure and 35 °C temperature after 8 hours of treatment. Effective removal of cytotoxic detergents from decellularized liver occurs already at a 150-bar pressure and does not require the addition of ethanol. Adding ethanol to sc-CO2 eliminates not only the cytotoxic, but also the cytostatic effect of tissue-specific scaffolds.Conclusion. Sc-CO2 treatment is an effective way to enhance the biocompatibility of three-dimensional porous matrices produced using cytotoxic substances: bifunctional crosslinking agents for biopolymer scaffolds and surfactants in the case of tissue-specific matrices. Addition of ethanol as a polarity modifier improves the treatment efficiency by eliminating both cytotoxic and cytostatic effects.

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