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Heat Transfer in Nonisothermal Liquid Injection Experiments in Porous Media

Description: This paper discusses an analysis of the heat transfer phenomena in the bench-scale experiments being carried out in the Stanford Geothermal Program. The basis of this analysis was a series of simplified mathematical models of heat and mass transport in fine-grained porous media. The analysis determined that the thermal capacity of the coreholder system caused heat losses from the core which were not steady at early and medium times. This phenomenon had not been recognized previously. This was in spite of the fact that various authors previously had attempted to match the experimental behavior under discussion with their sophisticated computer models. These computer models did not account for the transient nature of the heat losses from the core. 8 refs., 3 figs.
Date: December 3, 1976
Creator: Atkinson, Paul G.
Partner: UNT Libraries Government Documents Department

Buoyancy Induced Boundary Layer Flows in Geothermal Reservoirs

Description: Most of the theoretical study on heat and mass transfer in geothermal reservoirs has been based on numerical method. Recently at the 1975 NSF Workshop on Geothermal Reservoir Engineering, Cheng presented a number of analytical solutions based on boundary layer approximations which are valid for porous media at high Rayleigh numbers. according to various estimates the Rayleigh number for the Wairakei geothermal field in New Zealand is in the range of 1000-5000, which is typical for a viable geothermal field consisting of a highly permeable formation and a heat source at sufficiently high temperature. The basic assumption of boundary layer theory is that heat convective heat transfer takes place in a thin porous layer adjacent to heated or cooled surfaces. Indeed, numerical solutions suggest that temperature and velocity boundary layers do exist in porous media at high Rayleigh numbers. It is worth mentioning that the large velocity gradient existing near the heated or cooled surfaces is not due to viscosity but is induced by the buoyancy effects. The present paper is a summary of the work that we have done on the analytical solutions of heat and mass transfer in a porous medium based on the boundary layer approximations since the 1975 Workshop. As in the classical convective heat transfer theory, boundary layer approximations in porous layer flows can result in analytical solutions. Mathematically, the approximations are the first-order terms of an asymptotic expansion which is valid for high Rayleigh numbers. Comparison with experimental data and numerical solutions show that the approximations are also accurate at moderate values of Rayleigh numbers. For problems with low Rayleigh numbers where boundary layer is thick, higher-order approximations must be used. 9 refs., 5 figs.
Date: December 1, 1976
Creator: Cheng, Ping
Partner: UNT Libraries Government Documents Department

Geothermal Reservoir Engineering Research

Description: This report first describes reservoir engineering within the broad field of petroleum engineering. The report next describes the general pattern of reservoir engineering in terms of performance observations, hypothesis construction and testing, and reservoir development planning, and emphasizes the importance of searching for the hypothesis about the nature of the reservoir system derived from all known facts instead of a model that includes only selected fact. The history since 1900 of gas, oil, and geothermal reservoir engineering research is briefly described.
Date: December 1, 1976
Creator: Ramey, H.J. Jr. & Miller, Frank G.
Partner: UNT Libraries Government Documents Department

Bench-scale experiments in the Stanford Geothermal Project

Description: The Stanford Geothermal Project bench-scale experiments are designed to improve the understanding of geothermal reservoir physics. Three sets of experiments are discussed in the following sections: (1) vapor pressure lowering in porous media due to capillarity and adsorption, (2) the effect of temperature on absolute permeability, and (3) the determination of steam-water relative permeability for drainage processes.
Date: January 1, 1978
Creator: Counsil, J.R.; Hsieh, C.H.; Ehlig-Economides, C.; Danesh, A. & Ramey, H.J., Jr.
Partner: UNT Libraries Government Documents Department

Recent developments in well test analysis in the Stanford Geothermal Program

Description: In the past year a number of studies pertaining to geothermal well test analysis were conducted. In this paper a brief overview of progress on the following six subjects is presented: (1) earth tide effects on a closed reservoir, (2) transient pressure analysis of multilayered heterogeneous reservoirs, (3) interference testing with wellbore storage and skin at the producing well, (4) steam/water relative permeabilities, (5) transient rate and pressure buildup resulting from constant pressure production, and (6) transient pressure analysis of a parallelepiped reservoir.
Date: January 1, 1978
Creator: Ehlig-Economides, C.
Partner: UNT Libraries Government Documents Department

Pressure drawdown analysis for the Travale 22 well

Description: This work presents preliminary results on the analysis of drawdown data for Travale 22. Both wellhead pressure and flow rate data were recorded in this well for over a period of almost two years. In the past, Barelli et al. (1975) and Atkinson et al. (1977) presented the analysis of five pressure buildup tests. Figure 1 shows the Horner plot for these cases. They found that to have a good match in all cases, it was necessary to assume that the Travale 22 well is intersected by a partially penetrating vertical fracture in a parallel-piped whose bottom side is maintained at constant pressure (boiling front), as shown in Fig. 2. Atkinson et al. also presented an analysis for a pressure interface test run in the Travale-Radicondoli area. In this case, the Travale 22 well was flowing and the pressure recorded at wells R1, R3, R5, R6, R9, and Chl (see Fig. 3 ) . Analysis of these data showed that pressure interference in this reservoir can be matched by considering pure linear flow (Figs. 4 and 5 ) . This indicated the possible presence of a vertical fracture intersecting the Travale 22 well. It was determined that fracture is oriented along the N73{sup o}W direction. In addition, the pressure interference data showed that no boundary exists within 2 kilometers from the fracture plane. It was mentioned that linear flow should take place in both horizontal and vertical directions.
Date: January 1, 1978
Creator: Barelli, A.; Brigham, W.E.; Cinco, H.; Economides, M.; Miller, F.G.; Ramey, H.J., Jr. et al.
Partner: UNT Libraries Government Documents Department

A New Derivative Type-Curve for Pressure Buildup Analysis with Boundary Effects

Description: This study investigates pressure buildup behavior of wells with wellbore storage and skin in bounded circular reservoirs, when inner and outer boundary effects interact to fully or partially dominate the well pressure response. Using dimensionless pressure derivative as the dependent variable, we show that early time response is governed by C{sub D}e{sup 2S} and late time response by r{sub eD}{sup 2}/C{sub D}. Equations are provided to estimate the limits of the intermediate time period, which corresponds to infinite acting radial flow and a semi-log straight line on a pressure-time graph. We present a new buildup derivative type curve, incorporating inner boundary (early-time) and outer boundary (late-time) effects. Applications of this type curve in buildup test design and interpretation are discussed. 2 figs., 8 refs.
Date: January 20, 1987
Creator: Mishra, S. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department