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Evaluation of Cyclic Gas Injection in Enhanced Recovery from Unconventional Light Oil Reservoirs: Effect of Gas Type and Fracture Spacing

Figure 1. Schematic of two hydraulic fractures (HF) and SRV area with local grid refinement. SRV length is 450 ft. SRV width is variable; depending on fracture spacing.

Evaluation of Cyclic Gas Injection in Enhanced Recovery from Unconventional Light Oil Reservoirs: Effect of Gas Type and Fracture Spacing The economic profitability and reservoir performance are also investigated. Rate transient analysis is used to anticipate hydraulic fracture and effective fracture permeability. Different fracture spacings are selected as the major determinant

Groundwater baseline water quality in a shale gas exploration site and fracturing fluid-shale rock interaction

Fig. 2 The shallow groundwater chemical composition

At present, the baseline water quality must be firstly obtained to identify potential pollution of the activity and monitoring indicators should be studied for better environmental monitoring. We sampled shallow groundwater, produced waters, shale rock and soil in the Jiaoshiba shale-gas region, SW China and measurements have included water chemistry

Current research into the use of supercritical CO2 technology in shale gas exploitation

Fig. 3. Surface comparison of shale before and after ScCO2 fluid treatment (10 MPa, 50 °C) [53].

The research findings indicate that ScCO2 fluid replacement can be used to increase gas production and seal up greenhouse gases as an effective, clean and safe method of shale gas exploitation. It is particularly effective for promoting the desorption of CH4 in shale reservoirs that have developed fine neck-wide body

Sustainability of UK shale gas in comparison with other electricity options: Current situation and future scenarios

this paper integrates for the first time environmental, economic and social aspects of shale gas to evaluate its overall sustainability

Abstract Many countries are considering exploitation of shale gas but its overall sustainability is currently unclear. Previous studies focused mainly on environmental aspects of shale gas, largely in the US, with scant information on socio-economic aspects. To address this knowledge gap, this paper integrates for the first time environmental, economic and

Removal of organic compounds from shale gas flowback water

Fig. 1. Fractions of TOC (A) and molecular composition of LMW acid (B) and LMW neutral (C) fractions of the shale gas flowback water.

Abstract Ozonation, sorption to granular activated carbon and aerobic degradation were compared as potential treatment methods for removal of dissolved organic carbon (DOC) fractions and selected organic compounds from shale gas flowback water after pre-treatment in dissolved air flotation unit. Flowback water was characterised by high chemical oxygen demand and DOC.

Oil and gas wells and their integrity: Implications for shale and unconventional resource exploitation

Figure 1. Schematic diagram of typical well design, showing (A): structure of an exploration well; and (B): a production well. Depths to which different casings are used vary according to geology and pressure regime of drill site. Well diameter exaggerated to show sections more clearly.

The datasets vary considerably in terms of the number of wells examined, their age and their designs. Therefore the percentage of wells that have had some form of well barrier or integrity failure is highly variable (1.9%–75%). Of the 8030 wells targeting the Marcellus shale inspected in Pennsylvania between 2005

The shale gas revolution: Barriers, sustainability, and emerging opportunities

Fig. 1. Map of the Barnett Shale formation and production. The map illustrates the county-level spatial distribution of shale gas production (main map) and average per-well production rate (inset).

Abstract Shale gas and hydraulic refracturing has revolutionized the US energy sector in terms of prices, consumption, and CO2 emissions. However, key questions remain including environmental concerns and extraction efficiencies that are leveling off. For the first time, we identify key discoveries, lessons learned, and recommendations from this shale gas revolution

Investigating the traffic-related environmental impacts of hydraulic-fracturing (fracking) operations

Fig. 1. Physical and spatial concepts in the TIM.

Abstract Hydraulic fracturing (fracking) has been used extensively in the US and Canada since the 1950s and offers the potential for significant new sources of oil and gas supply. Numerous other countries around the world (including the UK, Germany, China, South Africa, Australia and Argentina) are now giving serious consideration to

The potential for spills and leaks of contaminated liquids from shale gas developments

Fig. 3. The number of sites that need to be developed before an incident or spill is likely to occur based on the petrol tankers data and minimum and maximum tanker numbers from the IoD report. Scenario 1: Single-well pad with 10 wells with 10 laterals developed over two years

Abstract Rapid growth of hydraulic fracturing for shale gas within the USA and the possibility of shale developments within Europe has created public concern about the risks of spills and leaks associated with the industry. Reports from the Texas Railroad Commission (1999 to 2015) and the Colorado Oil and Gas Commission

Shale gas exploitation: Status, problems and prospect

Fig. 2. Annual production of major shale gas plays in the world. Note: The data abroad are sourced from Refs. [14], [15], and the domestic data from Ref. [1]. Except for the Monteney and Muskwa shale gas plays in Canada of which the production data are shale gas production from 2011 to 2012, those of other plays are the data in 2015.

Shale gas reserves and production have been in a rapid growth in China owing to the Lower Paleozoic Wufeng and Longmaxi shale gas exploitation in the Sichuan Basin, which has become an important sector for the future increment of gas reserves and output in China. However, substantial progress has been

Potential impacts of emissions associated with unconventional hydrocarbon extraction on UK air quality and human health

Fig. 4 Monthly mean of the daily 1-h maximum surface NO2 in the control simulation (a) and simulated differences for the inclusion of fracking-related activity emissions in scenarios 1–4 (b–d) for June 2013.

Broadly speaking, our simulations indicate increases in both of these compounds across the UK air shed throughout the year. Changes in the 1-h maximum of NO2 and 8-h mean of O3 are particularly important for their human health impacts. These respective changes in NO2 and O3 would contribute to approximately

Exploring the endocrine activity of air pollutants associated with unconventional oil and gas extraction

Fig. 1 Number of UOG air sampling studies by geologic formation. Air sampling has been performed in various UOG sites in the US. The most commonly sampled site in studies identified by our search was the Barnett Shale located in TX.

In addition, a complex mixture of chemicals, including heavy metals, naturally-occurring radioactive chemicals, and organic compounds are released from the formations and can enter air and water. Compounds associated with UOG activity have been linked to adverse reproductive and developmental outcomes in humans and laboratory animal models, which is possibly

Effect of liquid nitrogen cooling on the permeability and mechanical characteristics of anisotropic shale

Fig. 2 TAW-100 servo-controlled triaxial testing system and assembled shale sample

(2) After LN2 cooling, the strength and brittleness of shale are obviously reduced, leading to the decrease in the ability of shale to resist deformation and failure, thereby helping to decrease the initiation pressure of reservoir stimulation. (3) The brittleness of shale will markedly increase during cryogenic fracturing, thus helping

The integrated feasibility analysis of water reuse management in the petroleum exploration performances of unconventional shale reservoirs

Fig. 2 Percentage of freshwater sources.

The objective of this comprehensive study is to conduct an investigation into the studied field and analyze the assessment of necessary water and produced water which is provided in the surface for reinjection procedures in the hydraulic fracturing and water injectivity; in respect of the way, petroleum and drilling industries