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Huseby O.,Institute for Energy Technology | Noevdal G.,International Research Institute of Stavanger | Sagen J.,Institute for Energy Technology
SPE Journal | Year: 2010

Natural tracers (geochemical and isotopic variations in injected and formation waters) are a mostly unused source of information in reservoir modeling. On the other hand, conventional interwell tracer tests are an established method to identify flow patterns. However, they are typically underexploited, and tracer-test evaluations are often performed in a qualitative manner and are rarely compared systematically to simulation results. To integrate naturaland conventional-tracer data in a reservoir-modeling workflow, we use the ensemble Kalman filter (EnKF), which has recently gained popularity as a method for history matching. The EnKF includes online update of parameters and the dynamical states. An ensemble of model representations is used to represent the model uncertainty. In this paper, we include conventional water tracers as well as natural tracers (i.e., geochemical variations) in the EnKF approach. The methodology is demonstrated by estimating permeability and porosity fields in a synthetic field case based on a real North Sea field example. The results show that conventional tracers and geochemical variations yield additional improvement in the estimates and that the EnKF approach is well suited as a tool to include in this process. The principal benefit from the methodology is improved models and forecasts from reservoir simulations, through optimal use of conventional and natural tracers. Some of the natural-tracer data (e.g., scale-forming ions and toxic compounds) are monitored for other purposes, and exploiting such data can yield significant reservoir-model improvement at a small cost. Copyright © 2010 Society of Petroleum Engineers.

News Article | April 13, 2016
Site: www.theenergycollective.com

Lightbridge, a company that was originally incorporated as Thorium Power, Inc., has achieved significant technology developments after making a strategic turn in 2010 from thorium based fuels to low enriched uranium metal alloy fuels. As funding dried up from the government agencies supporting their thorium work, the company chose to use its assembled nuclear engineering expertise to pivot to a more commercially attractive product line. On March 15, Lightbridge and Areva announced a joint development agreement (JDA) that will lead to a joint venture to develop and produce fuel for light water reactors using designs that Lightbridge patented in 2014. This agreement is in addition to previously announced agreements with BWXT Nuclear Energy and Canadian Nuclear Laboratories to fabricate partial length fuel rods for irradiation testing. Each of the partners in the Lightbridge-Areva JDA will share the cost of the work scope, with Areva’s contribution being mainly in kind access to specialized equipment and facilities. The exclusivity of the agreement is limited in time and scope. Lightbridge has obtained the final regulatory permissions needed to begin an operating temperature, pressure and irradiation testing program at the Halden Research Reactor in Norway in 2017. The company has a contract with Norway’s Institute for Energy Technology to perform the operating condition demonstration and the post irradiation examination at the nearby Studsvik facility in Sweden. The company’s 4th quarter 2015 business update provided all of that intriguing commercial information, but Atomic Insights readers crave more technical details. Seth Grae, CEO, Lightbridge and Jim Malone, the chief nuclear fuel development officer, agreed to discuss their technology’s characteristics and value proposition. Their company’s evolutionary fuel is designed to be a new and improved replacement for the light water reactor fuel — UO2 pellets in a zirconium tube — that has been the standard since the development of the Shippingport reactor in the mid 1950s. They walked me through the company’s current presentation and provided clarifying information. Near the beginning of our conversation, Seth said, “Here’s a phrase you don’t hear very often in the nuclear business – we are under budget and ahead of schedule.” Grae was upbeat to the point of being bubbly following a two-week period in which the company won the Technology Research Award at CleanEquity® Monaco 2016, announced a binding joint development agreement with Areva, held a business update conference call that provided additional announcements met with congratulations, and received favorable coverage from World Nuclear News, the Nuclear Energy Institute and Energy Policy. Lightbridge’s metal alloy fuel is positioned to be a non-disruptive improvement for nuclear power production that can be adapted to fit into a number of existing supply chains and established regulatory review processes. The newly developed individual fuel pins are substantially different from the existing UO2 pellets stacked into cylindrical zircalloy tubes, but they can be arranged into assemblies that are one-for-one replacements for existing assemblies in commercial PWRs, BWRs, and even light water SMRs. The guiding concept for the new design was to develop a fuel for existing power plants that would improve their utility and extend their economic service life. The resulting design produces increased power, extended fuel cycles, and enhanced safety margins. The cross-section of each individual fuel pin is a cruciform with all three of the component parts (cladding, fuel core and displacer) bonded to each other during fabrication. The fuel core is a uranium-zirconium alloy with much greater thermal conductivity than uranium dioxide. The displacer is an alloy containing burnable poisons for extended-life reactivity control. The cruciform pin shape provides approximately 35% more heat transfer surface area than cylindrical pins. The zirconium-niobium alloy cladding is slightly thicker on the edges of the pins, the places that appear as points on the cross section. During its development work for thorium based seed and blanket fuel assemblies, Lightbridge overcame the swelling issue that had limited previously developed low-alloy fuels by creating an alloy with roughly equal parts zirconium and uranium. The combination of pin shape, pin material, and metallurgic bonding results in an operating centerline temperature that is approximately 1000 ℃ cooler than in a conventional fuel pin. This large reduction in the fuel operating temperature provides several important safety benefits. To provide appropriate stiffness and support, the cruciform fuel pins are twisted and contact each other at 10 cm intervals along the length of a fuel assembly. This configuration eliminates the need for spacer grids and reduces flow resistance while still meeting seismic and vibration resistance requirements. The reduced core flow resistance produces increased reactor coolant flow rate when coolant pumps run at their designed power and speed. With higher coolant flow and constant core differential temperature, more thermal power can be moved from the core to the steam generators and into the steam turbines. The roughly 10% increase in electric power output provides an impressive internal rate of return on investment. If the Clean Power Plan is implemented as currently written, power uprates qualify for credits as a clean energy investment. By adjusting fuel loading and enrichment Lightbridge will be able to provide three variants for pressurized water reactors (PWR): LTB17-1024™ – up to 10% power uprates and 24-month operating cycles in existing PWRs; LTB17-1718™ – up to 17% power uprates and 18-month operating cycles in existing PWRs; and LTB17-3018™ – up to 30% power uprates and 18-month operating cycles in new-build PWRs. The 30% power uprate requires some modification of the containment design, fuel handling equipment, and the steam turbine. It is not considered cost effective for existing power plants. Introducing Lightbridge’s alloy fuel will require adjustments in the fuel cycle. Though still using low enriched uranium, longer operating cycles, higher thermal power and lower uranium content associated with the high alloy fuel require closer to 20% enrichment than the current 5% standard. Conversion after enrichment will be from UF6 to uranium metal instead of to UO2. Twisted cruciform fuel pins with bonded cladding will be extruded as a single full length piece. That manufacturing process is a complete shift from the current method loading UO2 pellets into zircalloy tubes. The metal alloy pins will not need internal springs, helium gas, spacer grids or end fixtures. The finished assemblies will be compatible with existing shipping containers, plant fuel handling equipment, and used fuel storage containers. There will be some modifications required in fuel pools to account for the higher fuel enrichment for new fuel and the initially higher decay heat production after removal from the reactor. Lightbridge’s strategy is to remain a technology provider and license holder. The company intends to enter into fabrication arrangements with multiple companies with limited exclusivity. Lightbridge’s Nuclear Fuel Utility Advisory Board includes senior fuel managers from four leading US utilities (Dominion, Duke, Exelon and Southern) that together operate 50% of the US nuclear generating fleet. In 2015, those companies submitted a letter to the NRC asking it to prepare to review Lightbridge’s fuel design in expectation of a license application submission in 2017 for first use of Lightbridge fuel in a commercial reactor in 2020. The post Lightbridge metallic alloy fuel provides upgrade path for LWRs appeared first on Atomic Insights.

Gola G.,Institute for Energy Technology | Nybo R.,Sintef | Sui D.,Sintef | Roverso D.,FirstSensing AS
Society of Petroleum Engineers - SPE Intelligent Energy International 2012 | Year: 2012

In oil and gas industries, drilling is a complex and critical operation which require constant and accurate real-time monitoring. To this aim, real-time models are required to provide an overview of the drilling operations when direct and reliable measurements are not available. Given the harsh operating environment, sensor reliability and calibration are critical issues and bad data quality is a typical problem which affects the accuracy of the model. As a result, the driller may be misled about the down-hole situation or receive conflicting claims about operating conditions. This paper presents two approaches based on the use of artificial intelligence to improve monitoring of drilling processes in terms of reduced uncertainty and increased confidence. The first exploits the aggregation of the opinion of different experts within a so-called ensemble approach; the second is based on a so-called grey-box approach which combines a physical model and artificial intelligence. The two approaches are applied to the problem of predicting the bottom-hole pressure during a managed pressure drilling operation to demonstrate the improved accuracy and robustness. Copyright 2012, Society of Petroleum Engineers.

Miroslaw L.,Institute for Energy Technology | Pantic M.,Institute for Energy Technology | Nordborg H.,Institute for Energy Technology
IoTBD 2016 - Proceedings of the International Conference on Internet of Things and Big Data | Year: 2016

The demand for computational power and storage in industry and academia is continuously increasing. One of the key drivers of this demand is the increased use of numerical simulations, such as Computational Fluid Dynamics for product development. This type of simulations generates huge amounts of data and demands massively parallel computing power. Traditionally, this computational power is provided by clusters, which require large investments in hardware and maintenance. Cloud computing offers more flexibility at significantly lower costs but the deployment of numerical applications is time-consuming, error-prone and requires a high level of expertise. The purpose of this paper is to demonstrate the SimplyHPC framework that automatizes the deployment of the cluster in the cloud, deploys and executes large scale and parallel numerical simulations, and finally downloads the results and shuts down the cluster. Using this tool, we have been able to successfully run the widely accepted solvers, namely PETSc, HPCG and ANSYS CFX, in a performant and scalable manner on Microsoft Azure. It has been shown that the cloud computing performance is comparable to on-premises clusters in terms of efficiency and scalability and should be considered as an economically viable alternative. Copyright © 2016 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved.

Yarushina V.M.,Institute for Energy Technology | Bercovici D.,Yale University
4th EAGE CO2 Geological Storage Workshop 2014: Demonstrating Storage Integrity and Building Confidence in CCS | Year: 2014

Fluid loss into reservoir rocks during hydraulic fracturing is modeled via a poro-elastoplastic pressure diffusion equation in which the total compressibility is a sum of fluid, rock and pore space compressibilities. Inclusion of pore compressibility and porosity-dependent permeability in the model leads to a strong pressure dependence ofleakoff. Dilation of the matrix due to fluid invasion causes higher rates of fluid leakoff. We suggest that certain features of leakoffbehavior might give an indication of the significance of the reservoir compaction/decompaction during fluid injection operations and distinguish different types of rock deformation (linear poroelastic, nonlinear poroelastic, poroelastoplastic). Copyright © (2014) by the European Association of Geoscientists & Engineers. All rights reserved.

Wangen M.,Institute for Energy Technology | Oye V.,Norsar | Wuestefeld A.,Norsar | Goertz-Allmann B.,Norsar | Souche A.,Institute for Energy Technology
4th EAGE CO2 Geological Storage Workshop 2014: Demonstrating Storage Integrity and Building Confidence in CCS | Year: 2014

We have presented a finite-element based model for simulation ofhydraulic fracturing. Each element is assigned strength in terms of a strain limit, and each element may have its individual strength. The element fractures when the strength limit is exceeded. One or more elements may break in one event. We show a 2D example of hydraulic fracturing of a low-permeable rock, where the fracture geometry is obtained. The bottom hole pressure is computed, which shows the pressure drops that follows each event. Finally, the magnitude of the fracture events is plotted in both space and time, which can be compared with the data from micro-seismic monitoring. A calibration of the model may provide effective parameter values for the rock. The presented formalism can also be coupled to reservoir simulators and calibrated against rupture propagation theories. Copyright © (2014) by the European Association of Geoscientists & Engineers. All rights reserved.

Yarushina V.M.,Institute for Energy Technology | Podladchikov Y.Y.,University of Lausanne | Simon N.S.C.,Institute for Energy Technology | Bercovici D.,Yale University
76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 | Year: 2014

A new fully coupled model of fluid flow through deformable viscoelastoplastic porous rock is developed. Constitutive evolution equations for porosity and densities of the solid matrix and the fluid are derived using effective media theory. Deformation and porosity-dependent permeability in the model lead to a strong pressure dependence of leakoff during hydraulic fracturing. Predicted rates of fluid loss are higher than those suggested by classical models. The model also allows investigation of the preferred upward flow pathways during fluid injection operations as observed in CO2 injection operations without invoking the hypothesis of a pre-existing fracture network. The model is applicable to soft and unconventional reservoirs whose mechanical behavior cannot be captured by simple elastic laws.

Simon S.C.,Institute for Energy Technology | Rass L.,University of Lausanne | Podladchikov Y.Y.,University of Lausanne | Souche A.,Institute for Energy Technology | Yarushina V.,Institute for Energy Technology
International Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage | Year: 2013

Large amounts of CO2 and other waste fluids are being injected into reservoirs all around the world. Preventing leakage of the fluids into sensitive ground water reservoirs and to the surface and assuring safe long terms storage are essential requirements in these operations. One example is the injection of about one million tons of CO2 per year since 1996 into the Utsira formation at Sleipner in the Norwegian North Sea. Conventional reservoir simulations fail to the formation of flow chanels or chimneys, and the fast spreading underneath the caprock. We developed a new numerical code that predicts the formation of chimneys as a consequence of coupled deformation-fluid flow, without prescribing pre-exiting fractures. Our 3D model includs full mechanics and visco-elastic deformation, allowing for simulation of injection into a pre-stressed reservoir. Observations that are used to evaluate our simulation results against resevoir data include pressure at the wellhead, CO2 filled porosity, CO2 flux over time, distribution of CO2 in the reservoir, spreading of CO2 underneath the caprock and pattern (chimney) fomation. Our model helps to understand and explain under which conditions localization of fluid will occure and is also applicable to the injection of other fluids (e.g. waste water).

Raeb L.,University of Lausanne | Yarushina V.M.,Institute for Energy Technology | Simon N.S.C.,Institute for Energy Technology | Podladchikov Y.Y.,University of Lausanne
2nd EAGE Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage | Year: 2015

High permeability fluid flow pathways are widely observed in nature, and their formation occurs on both geological and human timescales. Outcrop study as well as interpretation of seismic crob-section show clear evidences of these multi-scale vertical pipe features, where unconsolidated to loose material is present inside. Even if well documented, their formation proceb remains still not answered yet. We propose a physically consistent 3D two-phase model of focusing fluid flow that allow the formation of such vertical high permeability channels. Viscous or creep rheology is the key feature to explain this formation proceb. Our result show that the proposed mechanism triggers pipe formation where permeability increases over two orders of magnitude in impermeable shale, and with propagation speed close to 2 meters per year in these usual ceiling rocks. Our results are in good accordance with the values needed to explain the fast vertical breakthrough of CO2 plume in the layered Sleipner saline aquifer. © Copyright 2015 EAGE.

Yarushina V.,Institute for Energy Technology | Rab L.,University of Lausanne | Simon N.S.C.,Institute for Energy Technology | Podladchikov Y.Y.,University of Lausanne
2nd EAGE Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage | Year: 2015

New model of shear-induced dilation and shear-enhanced compaction in brittle (elastic) and ductile (viscous) rocks is proposed. The ebential feature of the model is the dependence of the porosity equation on the equivalent shear streb. This allows dilation of the pore space even at nominally comprebive effective prebures in agreement with experimental data. The implications for the formation of fluid-or gas-filled chimneys are considered. Spontaneous self-localization of Darcy flow in a deforming porous rock due to preferential dilation of the pore space is a viable mechanism for chimney formation. © Copyright 2015 EAGE.

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