ライブラリー Annual Energy Outlook 2000

Shale gas and non-aqueous fracturing fluids: Opportunities and challenges for supercritical CO2

There is a high demand of effective and eco-friendly corrosion inhibitor for industrial applications. In an attempt to prepare a benign and effective corrosion inhibitor for acidizing purpose, an imidazoline derivative, N-(2-(2-tridecyl-4,5-dihydro-1H-imidazol-1-yl)ethyl)tetradecanamide (NTETD) was synthesized from myristic acid and diethyleneamine. The characterization of the newly synthesized compound was done using 1H NMR, FTIR, and elemental analysis techniques. NTETD was examined as a corrosion inhibitor for low carbon steel in 15% HCl solution using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), linear polarization (LPR), scanning electron microscope (SEM), energy dispersive spectroscopy (EDAX), atomic force spectroscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. It was found that, the optimum concentration of NTETD is 300 mg/L. With this concentration, inhibition efficiency above 93% is achievable. Results from PDP show that, NTETD acted as a mixed type corrosion inhibitor but with principal effect on cathodic corrosion half reactions. The calculated value of the adsorption-desorption equilibrium constant (1.015 × 103) reveals a strong bonding between NTETD molecules and the steel surface. The EDAX, FTIR, and XPS results confirm the adsorption of NTETD molecules on the steel surface. SEM and AFM results agree with experimental findings that NTETD is effective in corrosion mitigation of steel in 15% HCl solution. The possible corrosion inhibition mechanism by NTETD has been proposed.

Myristic acid based imidazoline derivative as effective corrosion inhibitor for steel in 15% HCl medium.

Natural gas extraction is a greener solution to world energy resource depletion and water-based hydraulic fracturing is traditionally used to produce gas from deep and tight geological formations. However, since this practice fails to produce a commercially viable amount of gas and raises many environmental issues, better alternatives are being tested in the field, among which the usage of foam-based fluid is a comparatively novel but effective technique. The aim of this review is to understand the current opinion on foam-based fluid fracturing, its merits and demerits and the associated environmental footprint. Foams are made by mixing a gas phase with a liquid phase using a suitable surfactant, and the foam quality is composition-dependent, with high quality foams having higher percentages of gas. The properties of the injecting foam, including its rheology and viscosity, are important for the fracturing process. According to current studies, foams have two separate flow regimes (low and high quality) and a unique multiphase flow pattern. Foam viscosity should be low to enter the ends of the fracture and high to have a good proppant-carrying capacity. Greater proppant-carrying capacity, lower water consumption and chemical usage, quicker and easier fluid flowback and less environmental damage are the advantages of foam-based fracturing, and lack of knowledge, high capital cost, and potential damage to the environment from surfactants are the limitations. However, foam-based fracturing has been tested in very few locations to date.

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Current opinions on foam-based hydro-fracturing in deep geological reservoirs

Shale oil and gas resources contribute significantly to the energy production in the U.S. Greenhouse gas emissions come from combustion of fossil fuels from potential sources of power plants, oil refineries, and flaring or venting of produced gas (primarily methane) in oilfields. Economic utilization of greenhouse gases in shale reservoirs not only increases oil or gas recovery, but also contributes to CO2 sequestration. In this paper, the feasibility and efficiency of gas injection approaches, including huff-n-puff injection and gas flooding in shale oil/gas/condensate reservoirs are discussed based on the results of in-situ pilots, and experimental and simulation studies. In each section, one type of shale reservoir is discussed, with the following aspects covered: (1) Experimental and simulation results for different gas injection approaches; (2) mechanisms of different gas injection approaches; and (3) field pilots for gas injection enhanced oil recovery (EOR) and enhanced gas recovery (EGR). Based on the experimental and simulation studies, as well as some successful field trials, gas injection is deemed as a potential approach for EOR and EGR in shale reservoirs. The enhanced recovery factor varies for different experiments with different rock/fluid properties or models incorporating different effects and shale complexities. Based on the simulation studies and successful field pilots, CO2 could be successfully captured in shale gas reservoirs through gas injection and huff-n-puff regimes. The status of flaring gas emissions in oilfields and the outlook of economic utilization of greenhouse gases for enhanced oil or gas recovery and CO2 storage were given in the last section. The storage capacity varies in different simulation studies and is associated with well design, gas injection scheme and operation parameters, gas adsorption, molecular diffusion, and the modelling approaches.

A Review of Gas Injection in Shale Reservoirs: Enhanced Oil/Gas Recovery Approaches and Greenhouse Gas Control

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

State of the art report on waterless stimulation techniques for shale formations

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http://publications.jrc.ec.europa.eu/repository/bitstream/111111111/41356/1/reqno_jrc101696_jrc%20iet%20draft%20report%20on%20international%20developments%20-%20final.pdf

Gandossi Luca

Papers

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

State of the art report on waterless stimulation techniques for shale formations

International Developments in the Field of Unconventional Gas and Oil Extraction