Search results

The purpose of this study is to investigate the unstable propagation of parallel hydraulic fractures induced by interferences of adjacent perforation clusters and thermal diffusion. Fracture propagation in the process of multistage fracturing of a rock mass is deflected owing to various factors. Hydrofracturing of rock masses in deep tight reservoirs involves thermal diffusion, fluid flow and deformation of rock between the rock matrix and fluid in pores and fractures.

To study the unstable propagation behaviours of three-dimensional (3D) parallel hydraulic fractures induced by the interferences of adjacent perforation clusters and thermal diffusion, a 3D engineering-scale numerical model is established under different fracturing scenarios (sequential, simultaneous and alternate fracturing) and different perforation cluster spacings while considering the thermal-hydro-mechanical coupling effect. Stress disturbance region caused by fracture propagation in a deep tight rock mass is superimposed and overlaid with multiple fractures, resulting in a stress shadow effect and fracture deflection.

The results show that the size of the stress shadow areas and the interaction between fractures increase with decreasing multiple perforation cluster spacing in horizontal wells. Alternate fracturing can produce more fracture areas and improve the fracturing effect compared with those of sequential and simultaneous fracturing. The larger the temperature gradient between the fracturing fluid and rock matrix, the stronger the thermal diffusion effect, and the effect of thermal diffusion on the fracture propagation is significant.

This study focuses on the behaviours of the unstable dynamic propagation of 3D parallel hydraulic fractures induced by the interferences of adjacent perforation clusters and thermal diffusion. Further, the temperature field affects the fracture deflection requires could be investigated from the mechanisms; this paper is to study the unstable propagation of fractures in single horizontal well, which can provide a basis for fracture propagation and stress field disturbance in multiple horizontal wells.

Evaluating mechanical properties of simply made samples by 3D printing technology at nanoscale provides a clear path to better understand larger-scale responses of complex natural rocks. Therefore, to realize the similarity between synthetically manufactured materials and natural geomaterials, this study focused on nanoscale mechanical characterization of a 3D printed object with only two constituent components (gypsum powder and infiltrant).

The study method includes nanoindentation technique combined with numerical simulation via discrete element method (DEM).

Four typical load-displacement curves were identified from nanoindentation of total test points indicating a typical elastic-plastic behavior of the 3D printed gypsum rock sample. Mechanical parameters such as Young’s modulus and hardness were calculated by energy-based methods and a positive correlation was observed. The infiltrant was found to considerably be responsible for the majority of the sample nano-mechanical behavior rather than the gypsum particles, thus expected to control macroscale properties. This was decided from deconvolution and clustering of elastic modulus data. Particle flow modeling in DEM was used to simulate the nanoindentation process in a porous media yielding rock-alike mechanical behavior.

The results show a matching load-displacement response between experimental and simulation results, which verified the credibility of simulation modeling for mechanical behavior of 3D printed gypsum rock at nanoscale. Finally, differential effective medium theory was used to upscale the nanoindentation results to the macroscale mechanical properties, which provided an insight into the geomechanical modeling at multiscale.

Large-scale shale gas reserves have recently been identified under many parts of the UK and development pressure for detailed exploration and possibly the exploitation of these reserves by hydraulic fracturing, popularly described as fracking is growing rapidly and seems to have UK Government support. With this in mind the purpose of this paper is to offer a general review of the possible development of shale gas reserves by fracking within the UK and to explore a number of the planning and property issues associated with such development.

The briefing note begins with an outline of the characteristics of shale oil and the fracking process and of the initial developments within the UK and discusses some of the planning and property issues associated with such developments. The note is based upon information drawn from the internet sources, principally national and local governments, business organisations and environmental and community pressure groups and on visits to a small number of sites of exploratory fracking.

The note reveals that planning applications for exploratory and production fracking will be determined at local authority level rather as Nationally Significant Infrastructure Projects determined by the Secretary of State. In determining planning applications local authorities have received planning guidance from the UK Government and will need to consider a wide range of environmental factors but some critics suggest that the guidance is not comprehensive and that it is weighted in favour of granting permission. A number of property issues are also identified possible effects of fracking on property prices, the availability of mortgages and the insurance of properties.

This paper provides an accessible review of the development of shale gas resources by fracking within the UK and as such it will be of value to planners, developers, land and property professionals and students.

The purpose of this paper is to focus on the emerging phenomenon of medical tourism in the context of Iran from a customer experience management perspective and benchmark of their judgment including positive or negative, of the experience they have achieved of the Iranian health (medical) experience (CE) and suggest scenarios for the improvement of the Iranian customer experience management (CEM).

The research methodologies and research methods that are used in this descriptive-analytical research are based on an inspection of the remarkable literature related to medical tourism and customer experience management. The data gathering instrument is a researcher-made questionnaire based on the variables in the conceptual model extracted from the research literature. The study was conducted from May to August 2019. The population cohort of this study was the foreign patients calling selected Iranian hospitals and the sampling method was a purposive and snowball sample of prospective medical tourists. As the study was conducted throughout Iran, some important hospitals in Iran were selected by stratified sampling Yang et al. (2020b). The sample size and data saturation were 500 participants Lv and Song (2019). The collected data using the questionnaire were analyzed by SPSS software and statistical tests.

According to the results, the customer experience management statistical significance in the task aspect is (p = 0.0523), in the mechanical aspect is (p = 0.0563), in the human aspect is (p = 0.0544). The study showed positive customer experience among the patients who had been treated in the Iranian hospitals.

There is a lack of study that focuses on medical tourism and customer experience management in Iran. Therefore, based on the results of this study, the experience of medical tourists in Iran proved to be positive and satisfying. As little research has been conducted in the area of customer experience management (CEM) in Iranian medical tourism, future researchers can use these valuable results precisely and in more detail to benchmark more accurately the customer experience in all areas of medical and health tourism and other research areas in different aspects of CEM in Iran.

Large-scale shale gas reserves have recently been identified under many parts of the UK. Development pressure for detailed exploration and possibly the exploitation of these reserves by hydraulic fracturing, popularly described as fracking is growing rapidly and seems to have UK Government support. With this in mind the purpose of this paper is to offer a general review of the possible development of shale gas reserves by fracking within the UK and to explore a number of the property and investment issues associated with such development.

The briefing note begins with an outline of the characteristics of shale oil and the fracking process and of the initial developments within the UK and discusses some of the property and investment issues associated with such developments. The note is based upon information drawn from the internet sources, principally national and local governments, property, financial and environmental organisations and on visits to a small number of sites of exploratory fracking.

The paper identifies a wide range of potential environmental impacts associated with the development of shale gas reserves by fracking and reveals growing awareness in the UK that such development could have a major impact on property values, on the availability of mortgages and on property insurance. At the same time the paper also suggests that financial institutions are increasingly taking steps to minimise risks to their investments and reputation from potential environmental impacts.

The paper suggests a number of issues property managers and consultants will need to address in monitoring the impact of shale gas development by fracking on property values and it offers some guidelines to investment managers.

This paper provides an accessible review of the development of shale gas resources by fracking within the UK and as such it will be of value to a range of property and investment management professionals and to students pursuing property and investment courses.

The purpose of this paper was to examine UK shale gas viability. The recent commitment to shale gas exploration in the UK through fracking has given rise to well-publicised economic benefits and environmental concerns. There is potential for shale gas exploration in different parts of the UK over the next couple of decades. As argued in this study, if it does, it would transform the energy market and provide long-term energy security at affordable cost.

Interviews with senior practitioners and local communities were recorded, transcribed and entered into qualitative research software Nvivo. Validity and reliability were achieved by first assessing the plausibility in terms of already existing knowledge on some of the economic and environmental issues raised by participants.

Findings from this study suggest that environmental, health and safety risks can be managed effectively provided operational best practices are implemented and monitored by the Health and Safety Executive; Department of Energy, Climate Change; and the Mineral Planning Authorities. Participants further suggested that the integration of shale gas technology will protect consumers against rising energy prices and ensure that government does not get exposed to long-term geopolitical risks.

The present study corroborates the position that environmental, health and safety risks can be managed effectively provided operational best practices are implemented and monitored by the Health and Safety Executive; Department of Energy, Climate Change; and the Mineral Planning Authorities.

The present study confirms that the government is committed to ensuring that the nation maximises the opportunity that cost-effective shale gas technology presents, not just investment, cheap energy bills and jobs but providing an energy mix that will underpin the UK long-term economic prosperity.

The present study corroborates the position that environmental, health and safety risks can be managed effectively provided operational best practices are implemented and monitored by the Health and Safety Executive; Department of Energy, Climate Change; and the Mineral Planning Authorities. As shown in this study, the UK has a very strong regulatory regime compared to USA; therefore, environmental, health and safety risks will be very well managed and unlikely to escalate into the crisis being envisioned.

The purpose of this paper is to identify and characterize a geological storage site at more than 800 m depth that is capable of storing large quantities of carbon dioxide (CO₂) in the Alberta Basin and is close to a large CO₂ supply.

Five criteria are used to select the site: total volume of the pore space of the formation for CO₂ (i.e. capacity); accessibility of the pore space in the storage site to CO₂ (i.e. permeability or injectivity); ability of the storage site to retain the CO₂ once the CO₂ has been injected (i.e. containment); protection of other resources from contamination; and cost of the whole process: capture of the CO₂, transport and storage (i.e. economics).

The Heartland Redwater Leduc Reef is identified as a site that has large capacity, good injectivity, and is an excellent trap. Contamination of the oil in the oil reservoir at the top of the reef (the third largest oil reservoir in Canada) is avoided by co‐optimizing CO₂ storage and oil production.

The Heartland Redwater Leduc Reef is ideally located at relatively shallow depth (1,000‐1,200 m), has a large amount of residual oil and is close to large CO₂ sources which make it one of the most economically attractive sites in the Western Canadian Sedimentary Basin.

The Heartland Redwater Leduc Reef Saline Aquifer CO₂ Capture and Geological Storage Project (HARP) is investigating the technical and economic feasibility of injecting significant volumes of CO₂ into the large water‐saturated portion of a huge Devonian reef that is capped by a comparatively small oil reservoir, nevertheless the third largest oil pool in Canada. The reef has a total areal extent of nearly 600 km³, is more than 1,000 m deep and is up to 275 m thick. Based on the high‐water injectivity in the reef, the potential exists to inject sustainably in excess of 1,000 tonnes of CO₂ per day per well in the aquifer portion of the reef. Preliminary storage capacity estimates for the aquifer are in the order of one gigatonne of CO₂. The Heartland Redwater Leduc Reef has the combination of a large oil reservoir sitting on top of a much larger local aquifer. This is a unique site for storage in Canada and could be a model for the rest of the world for carbon dioxide capture and storage.

Background: Geostatistics focuses on spatial or spatiotemporal datasets. Geostatistics was initially developed to generate probability distribution predictions of ore grade in the mining industry; however, it has been successfully applied in diverse scientific disciplines. This technique includes univariate, multivariate, and simulations. Kriging geostatistical methods, simple, ordinary, and universal Kriging, are not multivariate models in the usual statistical function. Notwithstanding, simple, ordinary, and universal kriging techniques utilize random function models that include unlimited random variables while modeling one attribute. The coKriging technique is a multivariate estimation method that simultaneously models two or more attributes defined with the same domains as coregionalization.

Objective: This study investigates the impact of populations on traffic volumes as a variable. The additional variable determines the strength or accuracy obtained when data integration is adopted. In addition, this is to help improve the estimation of annual average daily traffic (AADT).

Methods procedures, process: The investigation adopts the coKriging technique with AADT data from 2009 to 2016 from Montana, Minnesota, and Washington as primary attributes and population as a controlling factor (second variable). CK is implemented for this study after reviewing the literature and work completed by comparing it with other geostatistical methods.

Results, observations, and conclusions: The Investigation employed two variables. The data integration methods employed in CK yield more reliable models because their strength is drawn from multiple variables. The cross-validation results of the model types explored with the CK technique successfully evaluate the interpolation technique's performance and help select optimal models for each state. The results from Montana and Minnesota models accurately represent the states' traffic and population density. The Washington model had a few exceptions. However, the secondary attribute helped yield an accurate interpretation. Consequently, the impact of tourism, shopping, recreation centers, and possible transiting patterns throughout the state is worth exploring.

Using the case of the Deepwater Horizon blowout in the Gulf of Mexico in 2010, I argue that the catastrophe was less an example of a low probability-high catastrophe event than an instance of socially produced risks and insecurities associated with deepwater oil and gas production during the neoliberal period after 1980. The disaster exposes the deadly intersection of the aggressive enclosure of a new technologically risky resource frontier (the deepwater continental shelf) with what I call a frontier of neoliberalized risk, a lethal product of cut-throat corporate cost-cutting, the collapse of government oversight and regulatory authority and the deepening financialization and securitization of the oil market. These two local pockets of socially produced risk and wrecklessness have come to exceed the capabilities of what passes as risk management and energy security. In this sense, the Deepwater Horizon disaster was produced by a set of structural conditions, a sort of rogue capitalism, not unlike those which precipitated the financial meltdown of 2008. The forms of accumulation unleashed in the Gulf of Mexico over three decades rendered a high-risk enterprise yet more risky, all the while accumulating insecurities and radical uncertainties which made the likelihood of a Deepwater Horizon type disaster highly overdetermined.

This research study aims to develop regular cylindrical pore network models (RCPNMs) to calculate topology and geometry properties of explosively created fractures along with their resulting hydraulic permeability. The focus of the investigation is to define a method that generates a valid geometric and topologic representation from a computational modelling point of view for explosion-generated fractures in rocks. In particular, extraction of geometries from experimentally validated Eulerian smoothed particle hydrodynamics (ESPH) approach, to avoid restrictions for image-based computational methods.

Three-dimensional stabilized ESPH solution is required to model explosively created fracture networks, and the accuracy of developed ESPH is qualitatively and quantitatively examined against experimental observations for both peak detonation pressures and crack density estimations. SPH simulation domain is segmented to void and solid spaces using a graphical user interface, and the void space of blasted rocks is represented by a regular lattice of spherical pores connected by cylindrical throats. Results produced by the RCPNMs are compared to three pore network extraction algorithms. Thereby, once the accuracy of RCPNMs is confirmed, the absolute permeability of fracture networks is calculated.

The results obtained with RCPNMs method were compared with three pore network extraction algorithms and computational fluid dynamics method, achieving a more computational efficiency regarding to CPU cost and a better geometry and topology relationship identification, in all the cases studied. Furthermore, a reliable topology data that does not have image-based pore network limitations, and the effect of topological disorder on the computed absolute permeability is minor. However, further research is necessary to improve the interpretation of real pore systems for explosively created fracture networks.

Although only laboratory cylindrical rock specimens were tested in the computational examples, the developed approaches are applicable for field scale and complex pore network grids with arbitrary shapes.

It is often desirable to develop an integrated computational method for hydraulic conductivity of explosively created fracture networks which segmentation of fracture networks is not restricted to X-ray images, particularly when topologic and geometric modellings are the crucial parts. This research study provides insight to the reliable computational methods and pore network extraction algorithm selection processes, as well as defining a practical framework for generating reliable topological and geometrical data in a Eulerian SPH setting.