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Title: Fractured Petroleum Reservoirs

Abstract

In this report the results of experiments of water injection in fractured porous media comprising a number of water-wet matrix blocks are reported for the first time. The blocks experience an advancing fracture-water level (FWL). Immersion-type experiments are performed for comparison; the dominant recovery mechanism changed from co-current to counter-current imbibition when the boundary conditions changed from advancing FWL to immersion-type. Single block experiments of co-current and counter-current imbibition was performed and co-current imbibition leads to more efficient recovery was found.

Authors:
Publication Date:
Research Org.:
National Petroleum Technology Office, Tulsa, OK (US)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE) (US)
OSTI Identifier:
750251
Report Number(s):
DOE/BC/14850-5
TRN: US200221%%469
DOE Contract Number:
FG22-96BC14850
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 18 Jan 2000
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; BOUNDARY CONDITIONS; COUNTER CURRENT; PETROLEUM; WATER

Citation Formats

Firoozabadi, Dr. Abbas. Fractured Petroleum Reservoirs. United States: N. p., 2000. Web. doi:10.2172/750251.
Firoozabadi, Dr. Abbas. Fractured Petroleum Reservoirs. United States. doi:10.2172/750251.
Firoozabadi, Dr. Abbas. Tue . "Fractured Petroleum Reservoirs". United States. doi:10.2172/750251. https://www.osti.gov/servlets/purl/750251.
@article{osti_750251,
title = {Fractured Petroleum Reservoirs},
author = {Firoozabadi, Dr. Abbas},
abstractNote = {In this report the results of experiments of water injection in fractured porous media comprising a number of water-wet matrix blocks are reported for the first time. The blocks experience an advancing fracture-water level (FWL). Immersion-type experiments are performed for comparison; the dominant recovery mechanism changed from co-current to counter-current imbibition when the boundary conditions changed from advancing FWL to immersion-type. Single block experiments of co-current and counter-current imbibition was performed and co-current imbibition leads to more efficient recovery was found.},
doi = {10.2172/750251},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 18 00:00:00 EST 2000},
month = {Tue Jan 18 00:00:00 EST 2000}
}

Technical Report:

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  • This report covers Task 3, Immiscible gas-oil flow in fractured/layered porous media, Part 1, Viscous displacement in fractured porous media: Experiments and Analysis of experiments and Task 5, Simulation of fractured reservoirs, Dual-porosity simulation incorporating reinfiltration and capillary continuity concepts, Part 3, Interaction between grid cells. In some fractured reservoirs, a gas pressure gradient of the order of 0.1 psi/ft may be established in the fractures due to flow. Such a pressure gradient could result in recovery enhancement of the matrix oil. Several tests were conducted to study viscous displacement in fractured porous media. These tests included both gravity drainagemore » with free gas displacement and forced gas displacement. The results show that there is considerable recovery improvement due to viscous displacement. Numerical results are in very good agreement with the experimental data. In Task 5, the authors propose a method which accounts for reinfiltration and capillary continuity not only within a grid cell, but also between various grid cells. A reinfiltration term is added to the dual-porosity model and the exchange term between the matrix and the fracture is calculated in a simple manner. Four example problems demonstrate the usefulness of the proposed method.« less
  • In a number of experiments, the efficiency of solution-gas drive for both a light and a heavy oil was studied. These experiments reveal that solution-gas drive for a heavy oil of 11 API gravity is more efficient than a light oil of 35 API gravity.
  • Very large compositional variation both areally and vertically has been observed in some hydrocarbon reservoirs. Several mechanisms are believed to contribute to such variations: gravitational segregation, molecular diffusion, thermal diffusion, and thermal convection. At isothermal conditions only gravitational segregation and molecular diffusion contribute to vertical compositional grading. The Gibbs segregation concept can properly account for this process. Under nonisothermal conditions, which is often the case, the process is thermodynamically irreversible and therefore Gibbs criteria of equilibrium cannot be invoked. The current literature often combines the Gibbs segregation concept and the natural convection process to formulate the interaction of convection andmore » gravity segregation for multicomponent systems at nonisothermal conditions. The Dary law is also used without the modification of the velocity weighing for multicomponent systems. Such a formulation may not describe the process properly. This report formulates compositional variation in hydrocarbon reservoirs at nonisothermal condition. Results for the special case of gravity and thermal diffusion are also presented.« less
  • The integral equation describing the nucleation and growth of bubbles in a supersaturated binary liquid mixture under constant expansion rate is considered. In case of macroscopically large number of microscopic nucleation sites, the solution is shown to exhibit weak dependence on the expansion rate in contradiction with experimental data. With few nucleation sites, the supersaturation extremum agrees with experimental data.
  • A number of experiments have been performed to study water injection in fractured porous media. These experiments reveal that: (1) the co-current imbibition may be the primary flow process in water-wet fractured media, and (2) the imbibition may result in over 20 percent recovery from very tight rock (Austin Chalk with K{sub ma} of the order of 0.01 md) for an imbibition period of about 2 months. Theoretical consideration reveal that the exponential function of Aronofsky et al. [``A Model for the Mechanism of Oil Recovery from Porous Matrix Due to Water Invasion In Fractured Reservoirs,`` Trans. AIME (1958) 213,more » 17-19] does not describe the early-time, but may represent the late-time recovery.« less