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At least 19 records

Oil Reservoir Properties Estimation Using Neutal Networks

This paper investigates the applicability as well as the accuracy of artificial neural networks for estimating specific parameters that describe reservoir properties based on seismic data. Our approach relies on JPL's adjoint operators general purpose neural network code to determine the best suited architecture. We believe that results presented in this work demonstrate that artificial neural networks produce surprisingly accurate estimates of the reservoir parameters.

oil reservoir neural networks geoscience data oil ↗

Multigrid Methods for Fully Implicit Oil Reservoir Simulation

In this paper we consider the simultaneous flow of oil and water in reservoir rock. This displacement process is modeled by two basic equations: the material balance or continuity equations and the equation of motion (Darcy's law). For the numerical solution of this system of nonlinear partial differential equations there are two approaches: the fully implicit or simultaneous solution method and the sequential solution method. In the sequential solution method the system of partial differential equations is manipulated to give an elliptic pressure equation and a hyperbolic (or parabolic) saturation equation. In the IMPES approach the pressure equation is first solved, using values for the saturation from the previous time level. Next the saturations are updated by some explicit time stepping method; this implies that the method is only conditionally stable. For the numerical solution of the linear, elliptic pressure equation multigrid methods have become an accepted technique. On the other hand, the fully implicit method is unconditionally stable, but it has the disadvantage that in every time step a large system of nonlinear algebraic equations has to be solved. The most time-consuming part of any fully implicit reservoir simulator is the solution of this large system of equations. Usually this is done by Newton's method. The resulting systems of linear equations are then either solved by a direct method or by some conjugate gradient type method. In this paper we consider the possibility of applying multigrid methods for the iterative solution of the systems of nonlinear equations. There are two ways of using multigrid for this job: either we use a nonlinear multigrid method or we use a linear multigrid method to deal with the linear systems that arise in Newton's method. So far only a few authors have reported on the use of multigrid methods for fully implicit simulations. Two-level FAS algorithm is presented for the black-oil equations, and linear multigrid for two-phase flow problems with strong heterogeneities and anisotropies is studied. Here we consider both possibilities. Moreover we present a novel way for constructing the coarse grid correction operator in linear multigrid algorithms. This approach has the advantage in that it preserves the sparsity pattern of the fine grid matrix and it can be extended to systems of equations in a straightforward manner. We compare the linear and nonlinear multigrid algorithms by means of a numerical experiment.

Molenaar, J.↗

Real Time Oil Reservoir Evaluation Using Nanotechnology

A method and system for evaluating status and response of a mineral-producing field (e.g., oil and/or gas) by monitoring selected chemical and physical properties in or adjacent to a wellsite headspace. Nanotechnology sensors and other sensors are provided for one or more underground (fluid) mineral-producing wellsites to determine presence/absence of each of two or more target molecules in the fluid, relative humidity, temperature and/or fluid pressure adjacent to the wellsite and flow direction and flow velocity for the fluid. A nanosensor measures an electrical parameter value and estimates a corresponding environmental parameter value, such as water content or hydrocarbon content. The system is small enough to be located down-hole in each mineral-producing horizon for the wellsite.

Li, Jing↗

Differential Muon Tomography to Continuously Monitor Changes in the Composition of Subsurface Fluids

Muon tomography has been used to seek hidden chambers in Egyptian pyramids and image subsurface features in volcanoes. It seemed likely that it could be used to image injected, supercritical carbon dioxide as it is emplaced in porous geological structures being used for carbon sequestration, and also to check on subsequent leakage. It should work equally well in any other application where there are two fluids of different densities, such as water and oil, or carbon dioxide and heavy oil in oil reservoirs. Continuous monitoring of movement of oil and/or flood fluid during enhanced oil recovery activities for managing injection is important for economic reasons. Checking on leakage for geological carbon storage is essential both for safety and for economic purposes. Current technology (for example, repeat 3D seismic surveys) is expensive and episodic. Muons are generated by high- energy cosmic rays resulting from supernova explosions, and interact with gas molecules in the atmosphere. This innovation has produced a theoretical model of muon attenuation in the thickness of rock above and within a typical sandstone reservoir at a depth of between 1.00 and 1.25 km. Because this first simulation was focused on carbon sequestration, the innovators chose depths sufficient for the pressure there to ensure that the carbon dioxide would be supercritical. This innovation demonstrates for the first time the feasibility of using the natural cosmic-ray muon flux to generate continuous tomographic images of carbon dioxide in a storage site. The muon flux is attenuated to an extent dependent on, amongst other things, the density of the materials through which it passes. The density of supercritical carbon dioxide is only three quarters that of the brine in the reservoir that it displaces. The first realistic simulations indicate that changes as small as 0.4% in the storage site bulk density could be detected (equivalent to 7% of the porosity, in this specific case). The initial muon flux is effectively constant at the surface of the Earth. Sensitivity of the method would be decreased with increasing depth. However, sensitivity can be improved by emplacing a greater array of particle detectors at the base of the reservoir.

Coleman, Max↗

Experimental study of bubble cavities attached to a rotating shaft in a reservoir

Bubble cavities formed by air entrainment and attached to a rotating shaft in an oil reservoir were studied. The cavities appear to the unaided eye as toroidal. High speed photography, however, reveals the individuality of the bubble cavities and their near solid body rotational characteristics. The cavities are distorted by the rotation effects but remain attached and tend to merge because of edge effects in the axial direction. The flow field within the reservoir is influenced by the unusual character of the two phase fluid found there; the vorticity is readily visualized. Other examples of vapor entrapment at the inlet of an eccentric rotor are also discussed. A simplified analytical method is provided, and a numerical analysis is being investigated. Vapor (void) entrainment and generation can significantly alter leakage rates and stability of seals, bearings, and dampers. Recognition of these effects in the component design systems will result only after detailed studies of the above phenomena.

Hendricks, R. C.↗

In-situ, On-demand Lubrication System for Space Mechanisms

Many of today's spacecraft have long mission lifetimes. Whatever the lubrication method selected, the initial lubricant charge is required to last the entire mission. Fluid lubricant losses are mainly due to evaporation, tribo-degradation, and oil creep out of the tribological regions. In the past, several techniques were developed to maintain the appropriate amount of oil in the system. They were based on oil reservoirs (cartridges, impregnated porous parts), barrier films, and labyrinth seals. Nevertheless, all these systems have had limited success or have not established a proven record for space missions. The system reported here provides to the ball-race contact fresh lubricant in-situ and on demand. The lubricant is stored in a porous cartridge attached to the inner or the outer ring of a ball bearing. The oil is released by heating the cartridge to eject oil, taking advantage of the greater thermal expansion of the oil compared to the porous network. The heating may be activated by torque increases that signal the depletion of oil in the contact. The low surface tension of the oil compared to the ball bearing material is utilized and the close proximity of the cartridge to the moving balls allows the lubricant to reach the ball-race contacts. This oil resupply system can be used to avoid a mechanism failure or reduce torque to an acceptable level and extend the life of the component.

Marchetti, Mario↗

Rapid subsidence over oil fields measured by SAR

The Lost Hills and Belridge oil felds are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of large volumes from shallow depths causes reduction in pore pressure and subsequent compaction, forming a surface subsidence bowl. We measure this subsidence from space using interferometric analysis of SAR (Synthetic Aperture Radar) data collected by the European Space Agency Remote Sensing Satellites (ERS-1 and ERS-2). Maximum subsidence rates are as high as 40 mm in 35 days or > 400 mm/yr, measured from interferograms with time separations ranging from one day to 26 months. The 8- and 26-month interferograms contain areas where the subsidence gradient exceeds the measurement possible with ERS SAR, but shows increased detail in areas of less rapid subsidence. Synoptic mapping of subsidence distribution from satellite data powerfully complements ground-based techniques, permits measurements where access is difficult, and aids identification of underlying causes.

synthetic aperture radar remote sensing oil fields↗

Activities of the Boom and Chassis Group

Group One of the NASA Lunar Enabler Project has designed the primary chassis and boom structures for the lunar vehicle. Both components also feature V-clamps that were adapted to interface connections within the structure. The chassis features a front end, rear end section, middle cross-section, and face plate. The rear section contains an extra compartment for the engine, hydraulic pump, fuel bottles, and oil reservoir necessary for the wheel drives. Each section consists of tubular aluminum 6061-T6. The boom features four degrees of freedom system, where the minimum factor of safety of any part is 1.5 (but, normally much higher). It consists of a tapered upper boom, lower boom, and three elbows that complement the articulation joints. Each section of the boom has been constructed from aluminum 6061-T6. There are four joints and eight V-clamps in the boom assembly. The V-clamps feature support rings that prevent axial rotation. They provide easy adaptability and assembly.

Dell, Jason Scott↗

Microgravity fluid physics research in the Space Station Freedom era

Microgravity fluid physics covers an exciting range of established and potential fields of scientific research. Areas in which the Microgravity Science and Applications Division of NASA's Office of Space Science and Applications is currently supporting research include: multiphase flow and phase change heat transfer, behavior of granular media and colloids; and interface dynamics, morphological stability, and contact line phenomena. As they contribute to our knowledge of fluid behavior, advances in these areas will enhance our understanding of materials processing on Earth and in space, and will contribute to technologies as diverse as chemical extraction, the prediction of soil behavior in earthquakes, and the production of oil reservoirs. NASA' s primary platform for research in microgravity fluid physics will soon be the Fluid Physics/Dynamics Facility on Space Station Freedom. This facility shares a rack for control and utilities with the Modular Combustion Facility, and has one rack for experiment-unique instruments. It is planned to change out the content of the experiment-unique rack at intervals on the order of one year. In order to obtain a maximum return on the operation of the facility during these intervals, the research community must carefully plan and coordinate an effort that brings the efforts of many investigators to bear on problems of particular importance. NASA is currently working with the community to identify research areas in which microgravity can make a unique and valuable contribution, and to build a balanced program of research around these areas or thrusts. Selections will soon be made from our first solicitation for research in fluid dynamics and transport phenomena. These solicitations will build the research community that will make Space Station Freedom a catalyst for scientific and technological discovery, and offer U.S. scientists in many disciplines a unique opportunity to participate in space science.

Carpenter, Bradley M.↗

Simulation Software

Various NASA Small Business Innovation Research grants from Marshall Space Flight Center, Langley Research Center and Ames Research Center were used to develop the 'kernel' of COMCO's modeling and simulation software, the PHLEX finite element code. NASA needed it to model designs of flight vehicles; one of many customized commercial applications is UNISIM, a PHLEX-based code for analyzing underground flows in oil reservoirs for Texaco, Inc. COMCO's products simulate a computational mechanics problem, estimate the solution's error and produce the optimal hp-adapted mesh for the accuracy the user chooses. The system is also used as a research or training tool in universities and in mechanical design in industrial corporations.

Source record↗

Haloanaerobium kushneri sp. nov., an obligately halophilic, anaerobic bacterium from an oil brine

Three strains, designated VS-751T, VS-511 and VS-732, of a strictly anaerobic, moderately halophilic, Gram-negative, rod-shaped bacterium were isolated from a highly saline (15-20%) brine from an oil reservoir in central Oklahoma, USA. The optimal concentration of NaCl for growth of these three strains was 2 M (12%), and the strains also grew in the presence of an additional 1 M MgCl2. The strains were mesophilic and grew at a pH range of 6-8. Carbohydrates used by all three strains included glucose, fructose, arabinose, galactose, maltose, mannose, cellobiose, sucrose and inulin. Glucose fermentation products included ethanol, acetate, H2 and CO2, with formate produced by two of the three strains. Differences were noted among strains in the optimal temperature and pH for growth, the maximum and minimum NaCl concentration that supported growth, substrate utilization and cellular fatty acid composition. Despite the phenotypic differences among the three strains, analysis of the 16S rRNA gene sequences and DNA-DNA hybridizations showed that these three strains were members of the same genospecies which belonged to the genus Haloanaerobium. The phenotypic and genotypic characteristics of strains VS-751T, VS-511 and VS-732 are different from those of previously described species of Haloanaerobium. It is proposed that strain VS-751T (ATCC 700103T) be established as the type strain of a new species, Haloanaerobium kushneri.

NASA Discipline Exobiology↗

Permanent Sequestration of Emitted Gases in the Form of Clathrate Hydrates

Underground sequestration has been proposed as a novel method of permanent disposal of harmful gases emitted into the atmosphere as a result of human activity. The method was conceived primarily for disposal of carbon dioxide (CO2, greenhouse gas causing global warming), but could also be applied to CO, H2S, NOx, and chorofluorocarbons (CFCs, which are super greenhouse gases). The method is based on the fact that clathrate hydrates (e.g., CO2 6H2O) form naturally from the substances in question (e.g., CO2) and liquid water in the pores of sub-permafrost rocks at stabilizing pressures and temperatures. The proposed method would be volumetrically efficient: In the case of CO2, each volume of hydrate can contain as much as 184 volumes of gas. Temperature and pressure conditions that favor the formation of stable clathrate hydrates exist in depleted oil reservoirs that lie under permafrost. For example, CO2-6H2O forms naturally at a temperature of 0 C and pressure of 1.22 MPa. Using this measurement, it has been calculated that the minimum thickness of continuous permafrost needed to stabilize CO2 clathrate hydrate is only about 100 m, and the base of the permafrost is known to be considerably deeper at certain locations (e.g., about 600 m at Prudhoe Bay in Alaska). In this disposal method, the permafrost layers over the reservoirs would act as impermeable lids that would prevent dissociation of the clathrates and diffusion of the evolved gases up through pores.

Duxbury, N.↗

Piston-Skirt Lubrication System For Compressor

Piston-skirt lubrication system provides steady supply of oil to piston rings of gas compressor. No need for oil-filled crankcase or external oil pump. Instead, part of each piston acts as its own oil pump circulating oil from reservoir. Annular space at bottom of piston and cylinder constitutes working volume of small oil pump. Depending on application, reservoir open to atmosphere, or sealed and pressurized in bellows to prevent contact between oil and atmosphere. Filter removes particles worn away from piston rings and cylinder wall during normal operation.

Schroeder, Edgar C.↗

A study of morphology, provenance, and movement of desert sand seas in Africa, Asia, and Australia

The author has identified the following significant results. The regional studies of sand seas made possible by analysis of ERTS-1 imagery have established that widespread patterns of eolian sand deposition exist in many places and that similarities and differences in these patterns can be measured and compared, on a worldwide scale. Analysis of the relationships of depositional patterns to controlling factors will require completion of the color mosaics of the test sites, and acquisition of adequate supporting ground truth data, especially wind data. Once analyses are complete, the results will be applicable to the regional study of ancient eolian sandstones. Such sandstones were formed many millions of years ago under conditions believed to be identical to those under which the sand seas that are observed being formed today. The understanding of the deposition of eolian sands provided by analysis of ERTS-1 imagery will be applicable to an understanding of the structure and distribution of ancient eolian sandstones and their potential as reservoirs of oil and water.

Mckee, E. D.↗

Landsat in the search for Appalachian hydrocarbons

A study has been conducted to determine the applicability of enhanced Landsat imagery for oil and gas exploration in Appalachia. Attention was given to the feasibility to employ lineaments identified on Landsat imagery as a tool in petroleum exploration. Lineaments, as defined in this connection, are linear or sublinear traces seen on Landsat imagery. They frequently reflect subsurface geological structures. The investigation was conducted in two stages. The first was designed to identify the specific Landsat imagery enhancement best suited for displaying lineaments. The second stage consisted of plotting lineaments and conducting an analysis of the lineament trends with regard to both local geological structure and regional tectonics. A close relationship was observed between lineaments identified on Landsat imagery and known oil and gas reservoirs. This result suggests that lineaments can be related to the structural control of oil and gas reservoirs throughout Appalachia.

Blodget, H. W.↗