Impacts of Confined Space on Production from Tight Reservoirs

This work develops a rigorous method for including confinement effects in fluid modeling. This method was implemented into phase modeling and compositional reservoir simulation to show the impacts of tight media on hydrocarbon phase behavior and production. The rigorous aspect of this method improves upon current methods of incorporating confinement effects in both fluid modeling and reservoir simulation. It is particularly useful for porous media with small pores, where the ratio of medium surface area to fluid volume and fluid-to-rock interaction are significant. The proposed model utilizes the Peng-Robinson equation of state coupled with the Young-Laplace equation for capillary pressure. The interfacial tension is determined using the parachor model, which is dependent on phase compositions and molar volumes. Capillary pressure is therefore implemented within the vapor-liquid equilibrium (VLE) calculations. Contact angle is an input and can be updated as a temperature-dependent function. When implemented inside the VLE loop, calculation time is minimally impacted, making this a very efficient method. Vapor-liquid equilibrium using this method for small pores is validated by modeling cases presented in published literature. These published data are obtained either experimentally or by using molecular simulation. In all cases, the model presented in this work is able to closely match phase behavior, showing a decrease in bubble point pressure, and an increase in dew point pressure. Changes in saturation pressure approach zero as the mixture critical point is approached. Implementation of this method into compositional reservoir simulation shows that confinement generally increases oil and gas production from tight oil reservoirs and generally decreases oil and gas production from tight gas condensate reservoirs, compared with the traditional bulk compositional simulators. Simple cases of a reservoir cell can be modeled with capillary pressure using a constant-composition expansion or constant-volume depletion method. This results in a capillary pressure curve as a function of liquid saturation. With these curves, relative permeability can be predicted by integration of the reciprocal of the square of capillary pressure. Reservoir simulation of an Eagle Ford reservoir fluid at various initial pressures shows the impact of capillary pressure and relative permeability on production. At high initial reservoir pressure, oil/gas relative permeability is insignificant, but capillary pressure still significantly impacts oil production. At lower initial pressure, capillary pressure and oil/gas relative permeability both significantly impact production

Inhibition of cartilage and bone destruction in adjuvant arthritis in the rat by a matrix metalloproteinase inhibitor

Considerable evidence has associated the expression of matrix metalloproteinases (MMPs) with the degradation of cartilage and bone in chronic conditions such as arthritis. Direct evaluation of MMPs' role in vivo has awaited the development of MMP inhibitors with appropriate pharmacological properties. We have identified butanediamide, N4- hydroxy-2-(2-methylpropyl)-N1-[2-[[2-(morpholinyl)ethyl]-,[S- (R*,S*)] (GI168) as a potent MMP inhibitor with sufficient solubility and stability to permit evaluation in an experimental model of chronic destructive arthritis (adjuvant-induced arthritis) in rats. In this model, pronounced acute and chronic synovial inflammation, distal tibia and metatarsal marrow hyperplasia associated with osteoclasia, severe bone and cartilage destruction, and ectopic new bone growth are well developed by 3 wk after adjuvant injection. Rats were injected with Freund's adjuvant on day 0. GI168 was was administered systemically from days 8 to 21 by osmotic minipumps implanted subcutaneously. GI168 at 6, 12, and 25 mg/kg per d reduced ankle swelling in a dose-related fashion. Radiological and histological ankle joint evaluation on day 22 revealed a profound dose related inhibition of bone and cartilage destruction in treated rats relative to rats receiving vehicle alone. A significant reduction in edema, pannus formation, periosteal new bone growth and the numbers of adherent marrow osteoclasts was also noted. However, no significant decrease in polymorphonuclear and mononuclear leukocyte infiltration of synovium and marrow hematopoietic cellularity was seen. This unique profile of antiarthritic activity indicates that GI168 is osteo- and chondro-protective, and it supports a direct role for MMP in cartilage and bone damage and pannus formation in adjuvant- induced arthritis

Geological discontinuity persistence: Implications and quantification

Persistence of geological discontinuities is of great importance for many rock-related applications in earth sciences, both in terms of mechanical and hydraulic properties of individual discontinuities and fractured rock masses. Although the importance of persistence has been identified by academics and practitioners over the past decades, quantification of areal persistence remains extremely difficult; in practice, trace length from finite outcrop is still often used as an approximation for persistence. This paper reviews the mechanical behaviour of individual discontinuities that are not fully persistent, and the implications of persistence on the strength and stability of rock masses. Current techniques to quantify discontinuity persistence are then examined. This review will facilitate application of the most applicable methods to measure or predict persistence in rock engineering projects, and recommended approaches for the quantification of discontinuity persistence. Furthermore, it demonstrates that further research should focus on the development of persistence quantification standards to promote our understanding of rock mass behaviours including strength, stability and permeability

The analysis of stress and strain in layered rock foundations with particular reference to the Farahnaz Pahlavi dam, Iran

Imperial Users onl

Thermodynamic Modeling of Pure Components Including the Effects of Capillarity

Capillarity is seen in many physical processes where fluids are confined in a porous medium. Fluid properties and flow are both theoretically and experimentally shown to change because of capillary effects. Owing to difficulty and expense in experimentally determining these properties in porous media with small pores, a mechanistic approach is taken to incorporate capillary effects in thermodynamic modeling. The Young–Laplace equation provides an ideal method, making the system a function of pore size and wettability, thus taking into account the porous material properties and fluid-to-material interactions. The method proposed here shows good agreement with both experimental data and molecular simulation. The advantage is its ease of application in thermodynamic modeling and relatively small computation requirement compared to molecular simulation. Because of capillarity, the phase envelope of pure substances is suppressed, indicating a change in phase density and liquid fraction. This method is a powerful tool in describing fluid behavior in porous media

Engineering the future: practitioners, researchers and policy makers working across sectors

Engineering the Future (EtF) is a three year project funded by EPSRC, which became operational in September 2006 and which is based in the Department of Electronic and Electrical Engineering of the University of Strathclyde and in the Departments of Electronics and Electrical Engineering and Educational Studies of the University of Glasgow. EtF seeks to address the challenges posed by the predicted shortfall between the numbers entering university engineering courses and the growing demands for graduate engineers to meet society's needs. To do so it aims to develop a methodology which sustains transformational change in engineering education. Using Electronic and Electrical Engineering (EEE) as a pilot study and located initially in Scotland, the Project's findings will be disseminated to ensure uptake on a UK basis

Engineering the future: Embedding engineering permanently across the school-university interface

This paper describes the design, implementation, and evaluation of an educational program. Engineering the Future (EtF) sought to promote a permanent, informed awareness within the school community of high-level engineering by embedding key aspects of engineering within the education curriculum. The Scottish education system is used for a case study in which a range of pilot high schools worked in close partnership with two university engineering departments. The study focuses on electronic/electrical engineering (EEE), a technically challenging area, which reflects many of the problems that are intrinsic to modern society. In so doing, the work also sought to support and refine the transition from the school environment to higher education engineering courses. EtF is founded on research into transformational change and describes the findings of a three-year program that sought to develop sustainable and transferable means of encouraging school students to study engineering at university. The authors describe the conditions needed to support sustainable developments. They also provide an analysis of inevitable constraints and suggest strategies to address these issues. The paper concludes that sustainable long-term promotion of engineering within schools to support the transition to university is possible if certain conditions are fulfilled. These conditions include the use of a model that facilitates partnerships among researchers, policy-makers, and practitioners in all sectors. Building such essential linkages is often challenging, but this effort is necessary if changes in engineering education are to be realized and sustained

DEVELOPMENT OF MPACT FOR FULL-CORE SIMULATIONS OF MAGNOX GAS-COOLED NUCLEAR REACTORS

The MPACT code, jointly developed by Oak Ridge National Laboratory and University of Michigan, is designed to perform high-fidelity light water reactor (LWR) analysis using wholecore pin-resolved neutron transport calculations on modern parallel-computing hardware. MPACT uses the subgroup method for resonance self-shielding, while the primary neutron transport solver uses a 2D/1D method that is based on the method of characteristics (MoC) for the x-y planes coupled with a 1D diffusion or transport solver in the axial dimension. Additional geometry capabilities are currently being developed in MPACT to support hexagonal-pitched lattices, as well as interstitial geometry (i.e., control rods at the corner of four adjacent pin cells). In this research, the MPACT method is tested on gas-cooled reactors by applying MPACT to full-core MAGNOX reactor test problems. MAGNOX test problems were chosen due to the availability of high-quality reactor design and validation data (available through an ongoing collaboration with the National Nuclear Laboratory in the United Kingdom) and the existence of a relatively complex axial power shape that is expected to challenge the MPACT method. MPACT’s convergence for partial- and full-core problems will be tested and verified. MPACT will be compared with high-fidelity continuous-energy Monte Carlo simulations to verify core reactivity, power distributions, and performance of the available cross section data libraries and energy group structures