Orr Jr., Franklin M.; SPE; New Mexico Petroleum Recovery Research Center Petroleum Recovery Research Center Silva, Matthew K.; SPE; New Mexico Petroleum Recovery Research Center Petroleum Recovery Research Center Lien, Cheng-Li; SPE; New Mexico Petroleum Recovery Research Center Abstract Results of phase composition and density measurements for CO2/ crude-oil mixtures at 32C and four pressures are reported for a system in which liquid/liquid and liquid/liquid/vapor phase separations occur. The experiments demonstrate that a CO2-rich liquid phase can contain as much as 30 wt% hydrocarbons and show that a CO2-rich vapor phase at the same conditions extracts hydrocarbons less efficiently. Pseudoternary phase diagrams are presented that summarize the results of the detailed phase composition measurements. Results of slim-tube displacements at the same four pressures are also given. They indicate that displacement is efficient when the pressure is high enough that a liquid CO2-rich phase appears. Predictions of the performance of the slim-tube displacements based entirely on the performance of the slim-tube displacements based entirely on the experimental measurements of phase compositions and densities are obtained using a simple one-dimensional (1D) simulator. The simulation results clarify the roles of phase behavior and volume change on mixing in the slim-tube tests. Finally, the advantages and limitations of the slimtube and continuous multiple-contact (CMC) tests are compared. We conclude that the CMC experiment yields more information useful for prediction of the performance of a CO2 flood. Introduction The laboratory experiment most commonly performed in the evaluation Of CO2 flood candidates is the slim-tube displacement. The experiment is an attempt to isolate the effects of phase behavior on displacement efficiency in a flow setting that minimizes the effects of the viscous instability inherent in the displacement of oil by low-viscosity CO2. It provides useful information about the pressure required to produce high displacement efficiency in an ideal porous medium. It is not, however, a direct measurement of the phase behavior Of CO2/crude-oil mixtures. The physical behavior of such mixtures is usually studied by combining known quantities of oil and CO2 in a visual cell and measuring phase volumes at various pressures. The volumetric data obtained, along with saturation pressure pressures. The volumetric data obtained, along with saturation pressure data, do not give any direct evidence concerning displacement efficiency, but they can be used to adjust and tune representations of the phase behavior with an equation of state (EOS). For instance, Sigmund et al., used that procedure to match EOS calculations to PVT data and then simulated slimtube displacement experiments, obtaining good agreement between calculation and experiment. Gardner et al., used a combination of phase composition and volumetric measurements to construct ternary diagrams phase composition and volumetric measurements to construct ternary diagrams for a CO2/crude-oil system and then used the ternary diagrams in 1D simulations of slim-tube displacements. They also obtained good agreement between calculation and experiment. Thus there is at least some experimental confirmation of the relationship between equilibrium phase behavior and flow in an ideal porous medium. The connection between phase behavior and displacement efficiency has, of course, long been recognized. SPEJ p. 281

The Waste Isolation Pilot Plant (WIPP) is a geological repository for disposal of U.S. defense transuranic radioactive waste. Built and operated by the U.S. Department of Energy (DOE), it is located in the Permian age salt beds in southeastern New Mexico at a depth of 655 m. Performance assessment for the repository's compliance with the 10,000-year containment standards was completed in 1996 and the U.S. Environmental Protection Agency (EPA) certified in 1998 that the repository meets compliance with the EPA standards 40 CFR 191 and 40 CFR 194. The Environmental Evaluation Group (EEG) review of the DOE's application for certification identified a number of issues. These related to the scenarios, conceptual models, and values of the input parameters used in the calculations. It is expected that these issues will be addressed and resolved during the first 5-year recertification process that began with the first receipt of waste at WIPP on March 26, 1999, and scheduled to be completed in March 2004.

No abstract

The Waste Isolation Pilot Plant (WIPP) is a geological repository for disposal of U.S. defense transuranic radioactive waste. Built and operated by the U.S. Department of Energy (DOE), it is located in the Permian age salt beds in southeastern New Mexico at a depth of 655 m. Performance assessment for the repository's compliance with the 10,000-year containment standards was completed in 1996 and the U.S. Environmental Protection Agency (EPA) certified in 1998 that the repository meets compliance with the EPA standards 40 CFR 191 and 40 CFR 194. The Environmental Evaluation Group (EEG) review of the DOE's application for certification identified a number of issues. These related to the scenarios, conceptual models, and values of the input parameters used in the calculations. It is expected that these issues will be addressed and resolved during the first 5-year recertification process that began with the first receipt of waste at WIPP on March 26, 1999, and scheduled to be completed in March 2004.

No abstract