Hydraulic fracturing has been used by the oil and gas industry as a way to boost hydrocarbon production since 1947. Recent advances in fracturing technologies, such as multistage fracturing in horizontal wells, are responsible for the latest hydrocarbon produc- tion boom in the US. Linear or crosslinked guars are the most commonly used fluids in traditional fracturing operations. The main functions of these fluids are to open/propagate the fractures and transport proppants into the fractures. Proppants are usually applied to form a thin layer between fracture faces to prop the fractures open at the end of the fracturing process. Chemical breakers are used to break the polymers at the end of the fracturing process so as to provide highly conductive fractures. Concerns over fracture conduc- tivity damage by viscous fluids in ultra-tight formations found in unconventional reservoirs prompted the industry to develop an alter- native fracturing fluid called "slickwater". It consists mainly of water with a very low concentration of linear polymer. The low concentration polymer serves primarily to reduce the friction loss along the flow lines. Proppant-carrying capability of this type of fluids is still a subject of debate among industry experts. Constraints on local water availability and the potential for damage to formations have led the industry to develop other types of fracturing fluids such as viscoelastic surfactants and energized fluids. This article reviews both the traditional viscous fluids used in conventional hydraulic fracturing operations as well as the new family of fluids being devel- oped for both traditional and unconventional reservoirs. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131 ,4 0735.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/app.40735

A review of fracturing fluid systems used for hydraulic fracturing of oil and gas wells

A review of the current progress of CO2 injection EOR and carbon storage in shale oil reservoirs

http://nlhfrp.ca/wp-content/uploads/2015/01/1-s2.0-S0304389414003021-main.pdf

Physical, chemical, and biological characteristics of compounds used in hydraulic fracturing

Application of nanotechnology by means of nanoparticles and nanodispersions in oil recovery - A comprehensive review

The technology of hydraulic fracturing for hydrocarbon well stimulation is not new, but only fairly recently has become a very common and widespread technique, especially in North America, due to technological advances that have allowed extracting natural gas from so-called unconventional reservoirs (tight sands, coal beds and shale formations). The conjunction of techniques such as directional drilling, high volume fracturing, micro-seismic monitoring, etc. with the development of multi-well pads has been especially successful in the last years in their application to shales, making gas production from shales technically and economically feasible. In Europe, the potential application of this technology has led to both great worries and high expectations: worries regarding the alleged magnitude of the environmental impact, and expectations about production of indigenous hydrocarbons. Other types of formation stimulation exist that do not make use of water-based fluids (for instance, explosive fracturing, dynamic loading, etc.), or that make use of fluids other than water. These are currently not extensively applied due to performance considerations. As for any other industrial activity, the deployment of high-volume hydraulic fracturing could potentially entail some risks to the environment. Among the concerns raised are high usage of water, methane infiltration in aquifers, aquifer contamination, extended surface footprint, induced local seismicity, etc. New technologies could help addressing these concerns (for instance by using non-toxic chemicals, by reducing or eliminating altogether the usage of water, by considerably reducing the surface footprint of a well, etc.). This report reviews hydraulic fracturing and alternative fracturing technologies, by searching the open literature, patent databases and commercial websites (mainly in the English language). For each identified technique, an overview is given. The technique is then briefly explained, and its rationale (reasons for use) is identified. Potential advantages and disadvantages are identified, and some considerations on costs are given. Finally, the status of the technique (for instance, commercially applied, being developed, concept, etc.) is given for its application to shale gas production. As the Commission’s in-house science service, the Joint Research Centre’s mission is to provide EU policies with independent, evidence-based scientific and technical support throughout the whole policy cycle. Working in close cooperation with policy Directorates-General, the JRC addresses key societal challenges while stimulating innovation through developing new standards, methods and tools, and sharing and transferring its know-how to the Member States and international community. Key policy areas include: environment and climate change; energy and transport; agriculture and food security; health and consumer protection; information society and digital agenda; safety and security including nuclear; all supported through a cross- cutting and multi-disciplinary approach. L D -N A -2 6 3 4 7 -E N -N

/pdf/an-overview-of-hydraulic-fracturing-and-other-formation-b2rkdo3z29.pdf

An overview of hydraulic fracturing and other formation stimulation technologies for shale gas production

A Systematic Procedure to Describe Shale Gas Permeability Evolution during the Production Process

Application of Raman Spectroscopy in Investigating the Effect of Source and Temperature on the Maturity of the Organic Matter Exposed to Hydrocarbon Gas Injection

There exits a great challenge to evaluate the flow properties of tight porous media even at the core scale. A pulse-decay experiment is routinely used to measure the petrophysical properties of tight cores including permeability and porosity. In this study, 5 sets of pulse-decay experiments are performed on a tight heterogeneous core by flowing nitrogen in the forward and backward directions under different pressures under pore pressures approximately from 100 psi to 300 psi. Permeability values from history matching are from about 300 nD to 600 nD which shows a good linear relationship with the inverse of pore pressure. A preferential flow path is found even when the microcrack is absent. The preferential path causes different porosity values using differential initial upstream and downstream pressure. In addition, the porosity values calculated based on the forward and backward flow directions are also different, and the values are about 1.0% and 2.3%, respectively, which is the primary novelty of this study. The core heterogeneity effect significantly affects the very early stage of pressure responses in both the upstream and downstream but the permeability values are very close in the late-stage experiment. We proposed that that there are two reasons for the preferential flow path: the Joule–Thomson effect for non-ideal gas and the core heterogeneity effect. Based on the finding of this study, we suggest that very early pressure response in a pulse-decay experiment should be closely examined to identify the preferential flow path, and failure to identify the preferential flow path leads to significant porosity and permeability underestimation.

https://www.mdpi.com/1996-1073/12/18/3559/pdf

Impact of Heterogeneity on the Transient Gas Flow Process in Tight Rock

Injection of polymeric solutions in order to propagate a fracture and carry proppants to keep the fracture open is a common practice in hydraulic fracturing of ultra-tight formations. Polymeric fluids open and extend the already existing network of fractures. Considering the low permeability of the formation, small width of the micro-fractures, and the importance of fracture cleanup during the production phase, using breakers is recommended to degrade the more concentrated polymeric fluid and increase the conductivity of the fractures. Enzymes are typically used successfully as breakers for fracturing fluids. In this study, the effect of high shear rates on the activity of enzymes was studied. Enzyme activity decreased at increasing shear rates. However, this activity reduction is reversible. This proves insignificant damage to the enzyme structure due to shear effects. This will assure the activity of the enzymes after reaching the fracture and the more efficient cleanup of the fracture(s). [Received: 31 July 2013; Accepted: 26 January 2014].

Effect of shear rate on the activity of enzymes used in hydraulic fracture cleanup of tight unconventional reservoirs

Mesenchymal stem cells (MSCs) have the ability to migrate into tumor sites and release growth factors to modulate the tumor microenvironment. MSC therapy have shown a dual role in cancers, promoting or inhibiting. However, MSCs could be used as a carrier of anticancer agents for targeted tumor therapy. Recent technical improvements also allow engineering MSCs to improve tumor-targeting properties, protect anticancer agents, and decrease the cytotoxicity of drugs. While some of MSC functions are mediated through their secretome, MSCs-derived extracellular vesicles (EVs) are also proposed as a possible viechle for cancer therapy. EVs allow efficient loading of anticancer agents and have an intrinsic ability to target tumor cells, making them suitable for targeted therapy of tumors. In addition, the specificity and selectivity of EVs to the tumor sites could be enhanced by surface modification. In this review, we addressed the current approaches used for engineering MSCs and EVs to effectively target tumor sites and deliver anticancer agents. 

Reza Barati

Papers

A Systematic Procedure to Describe Shale Gas Permeability Evolution during the Production Process

Application of Raman Spectroscopy in Investigating the Effect of Source and Temperature on the Maturity of the Organic Matter Exposed to Hydrocarbon Gas Injection

Impact of Heterogeneity on the Transient Gas Flow Process in Tight Rock

Effect of shear rate on the activity of enzymes used in hydraulic fracture cleanup of tight unconventional reservoirs

Recent advancements to engineer mesenchymal stem cells and their extracellular vesicles for targeting and destroying tumors.