Aerospace medicine and biology: A continuing bibliography with indexes, supplement 184

This bibliography lists 139 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1978

Numerical simulation and interpretation of formation-tester measurements acquired in the presence of mud-filtrate invasion

textWireline formation testers (WFT) are widely used to measure fluid pressure, to perform downhole fluid analysis in real-time, and for estimating permeability through pressure transient testing. Formation testers can measure a range of fluid properties such as color, viscosity, density, composition, pH, optical refractive index, pressure, salinity, fractional flow, and gas-oil ratio (GOR). However, WFT measurements are influenced by the process of mud-filtrate invasion because overbalanced drilling promotes radial displacement of in-situ fluids by mud filtrate. Oil-base mud (OBM) is first-contact miscible with native oil and can lead to contaminated fluid samples, erroneous estimates of petrophysical properties, and changes of composition, viscosity, compressibility, GOR, and fluid density. The objective of this dissertation is three-fold: (1) to quantify the effect of OBMfiltrate invasion on WFT measurements, (2) to estimate in-situ petrophysical properties concomitantly from transient measurements of pressure, flow rate and GOR acquired with formation testers, and (3) to quantify petrophysical, geometrical, and fluid properties that can minimize the time of withdrawal of uncontaminated fluid samples. In order to quantify the effect OBM-filtrate invasion on WFT measurements, we develop a two-dimensional axial-symmetric compositional simulator and subsequently use a commercial adaptive-implicit compositional simulator, CMG-GEM1. History matching of three field data sets acquired with probe-type formation testers in light-oil formations accurately reproduces measurements of sandface pressure, observation-probe pressure, GOR, and flow rate. Further, we demonstrate that history matching enables the detection and diagnosis of adverse data-acquisition conditions such as plugging, noisy data, and presence of OBM-filtrate invasion. We introduce a dimensionless fluid contamination function that relates GOR to fluid-sample quality. Sensitivity analysis of simulated fluid-sample quality to petrophysical properties clearly indicates that sample quality improves in the presence of anisotropy and impermeable shale boundaries. A computationally efficient dual-grid inversion algorithm is developed and tested on both synthetic and field data sets to estimate in-situ petrophysical properties from WFT measurements. These tests confirm the reliability and accuracy of the inversion technique. Results indicate that permeability estimates can be biased by noisy measurements as well as by uncertainty in flow rate, relative permeability, radial invasion length, formation damage, and location of bed boundaries. To quantify petrophysical and geometrical factors that can optimize the time of withdrawal of uncontaminated fluid samples, we compare the performance of focused and conventional probe-type WFT in the presence of mud-filtrate invasion. Simulations indicate a significant reduction in fluid-cleanup time when using a focused probe. The specific amount of improvement depends on probe geometry, fluid composition, and petrophysical properties of the probed formation. Finally, we develop an inversion method to estimate Brooks-Corey parametric saturation-dependent functions jointly from transient measurements of fractional flow and probe pressure. Results show that estimating Brooks-Corey parameters can be nonunique if the a-priori information about fluid and petrophysical properties is uncertain. However, we show that focused fluid sampling consistently improves both the accuracy and reliability of the estimated relative permeability and capillary pressure parametric functions with respect to estimates obtained with conventional-probe measurements.Petroleum and Geosystems Engineerin

A quantitative estimation of regulation and transport limitations in the human cardiopulmonary system

The object of this dissertation is to quantitatively describe the regulation of some of the exchange processes within the human body. Conceptually this dissertation is divided into two sections. In the first section a macroscopic view was adopted to describe the overall regulation of the cardiovascular and respiratory systems. These overall system models were used as heuristic tools to gain an understanding of physiological behavior in micro-gravity. In the second section, a microscopic view was used to estimate the role played by the surfactant system of the lung in regulating the transfer of fluid across the pulmonary-capillary wall;The basis of the cardiovascular system model is the maintenance of arterial blood pressure homeostasis. Sub-models constituting the overall model are: the pressure-flow model, the heart action model, the controller model which describes short term-control, and the renal model which describes long term control and the regulation of total body water content. Model predictions show that incorporating the fluid shift from the lower to the upper part of the body in micro-gravity is sufficient to account for the cardiovascular changes occurring in micro-gravity;The respiratory model is concerned with the maintenance of a constant carbon dioxide level in the tissue and body fluids. The sub-models constituting the overall respiratory model are: the gas-exchange model, the mechanics model, and the controller model which determines the ventilation and cardiac output on the basis of arterial blood gas tensions. Simulation results show that pleural pressure homogeneity, increased lung diffusing capacity and decreased lung volume are sufficient to describe respiratory changes in micro-gravity;In the penultimate section the lung mechanics model is coupled with a model of fluid exchange across the pulmonary-capillary wall. The lung mechanics model estimates the influence of the surfactant system of the lung in controlling the interstitial space hydrostatic pressure while the fluid exchange model determines the influence of the interstitial space hydrostatic pressure in regulating fluid movement across the pulmonary-capillary wall. This model quantitatively estimates the influence of the surfactant alone in regulating fluid movement across the pulmonary-capillary wall

Numerical simulation and optimisation of IOR and EOR processes in high-resolution models for fractured carbonate reservoirs

Carbonate reservoirs contain more than half of the world’s conventional hydrocarbon resources. Hydrocarbon recovery in carbonates, however, is typically low, due to multi-scale geological heterogeneities that are a result of complex diagenetic, reactive, depositional and deformational processes. Improved Oil Recovery (IOR) and Enhanced Oil Recovery (EOR) methods are increasingly considered to maximise oil recovery and minimise field development costs. This is particularly important for carbonate reservoirs containing fractures networks, which can act as high permeability fluid flow pathways or impermeable barriers during interaction with the complex host rock matrix. In this thesis, three important contributions relating to EOR simulation and optimisation in fractured carbonate reservoirs are made using a high-resolution analogue reservoir model for the Arab D formation. First, a systematic approach is employed to investigate, analyse and increase understanding of the fundamental controls on fluid flow in heterogeneous carbonate systems using numerical well testing, secondary and tertiary recovery simulations. Secondly, the interplay between wettability, hysteresis and fracture-matrix exchange during combined CO2 EOR and sequestration is examined. Finally, data-driven surrogates, which construct an approximation of time-consuming numerical simulations, are used for rapid simulation and optimisation of EOR processes in fractured carbonate reservoirs while considering multiple geological uncertainty scenarios

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 197, September 1979

This bibliography lists 193 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1979

Thermal-Hydraulics in Nuclear Fusion Technology: R&D and Applications

In nuclear fusion technology, thermal-hydraulics is a key discipline employed in the design phase of the systems and components to demonstrate performance, and to ensure the reliability and their efficient and economical operation. ITER is in charge of investigating the transients of the engineering systems; this included safety analysis. The thermal-hydraulics is required for the design and analysis of the cooling and ancillary systems such as the blanket, the divertor, the cryogenic, and the balance of plant systems, as well as the tritium carrier, extraction and recovery systems. This Special Issue collects and documents the recent scientific advancements which include, but are not limited to: thermal-hydraulic analyses of systems and components, including magneto-hydrodynamics; safety investigations of systems and components; numerical models and code development and application; codes coupling methodology; code assessment and validation, including benchmarks; experimental infrastructures design and operation; experimental campaigns and investigations; scaling issue in experiments

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 130, July 1974

This special bibliography lists 291 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1974

Institute of Safety Research; Annual Report 1997

The report gives an overview on the scientific work of the Institute of Safety Research in 1997

Estimation of fracture porosity in an unsaturated fractured welded tuff using gas tracer testing

Kinematic fracture porosity is an important hydrologic transport parameter for predicting the potential of rapid contaminant migration through fractured rock. The transport velocity of a solute moving within a fracture network is inversely related to the fracture porosity. Since fracture porosity is often one or two orders of magnitude smaller than matrix porosity, and fracture permeability is often orders of magnitude greater than matrix permeability, solutes may travel significantly faster in the fracture network than in the surrounding matrix. This dissertation introduces a new methodology for conducting gas tracer tests using a field portable mass spectrometer along with analytical tools for estimating fracture porosity using the measured tracer concentration breakthrough curves. Field experiments were conducted at Yucca Mountain, Nevada, consisting of air-permeability transient testing and gas-tracer-transport tests. The experiments were conducted from boreholes drilled within an underground tunnel as part of an investigation of rock mass hydrological behavior. Air-permeability pressure transients, recorded during constant mass flux injections, have been analyzed using a numerical inversion procedure to identify fracture permeability and porosity. Dipole gas tracer tests have also been conducted from the same boreholes used for air-permeability testing. Mass breakthrough data has been analyzed using a random walk particle-tracking model, with a dispersivity that is a function of the advective velocity. The estimated fracture porosity using the tracer test and air-injection test data ranges from .001 to .015. These values are an order of magnitude greater than the values estimated by others using hydraulically estimated fracture apertures. The estimates of porosity made using air-permeability test data are shown to be highly sensitive to formation heterogeneity. Uncertainty analyses performed on the gas tracer test results show high confidence in the parameter estimates made