Rock cores

The area between the Siquieros and Clipperton Transforms on the East Pacific Rise at 8-10°N (often referred to as 9°N ) has been a focus of intense study over the past 10 years. The first U-series work in this area involved combined °Th and Pa analyses of samples collected by submersible, rock coring and dredging along the southern portion of 9°N (Goldstein et al. 1993) (Fig. 3). Volpe and Goldstein (1993) analyzed three of these... 

Another series of experiments used sandstone cores previously injected with starved bacteria to investigate the ability of the bacteria to grow within rock cores when given a suitable nutrient Berea sandstone cores of 200 and 400 millidarcy (md) permeabilities were used as they were considered to be more representative of reservoir conditions than the glass bead cores. The sandstone cores were injected with 300 to 450 pore volumes of 10 /ml starved bacteria until the cores contained an even distribution of bacteria (Fig. 3A B) and the core permeabilities were between 13% and 18%. SCM nutrient was injected through the cores (Fig. 3C) until the core permeability fell to 0.1%, this required 360 pore volumes of SCM. 

Figure 3. Diagrammatic representation of the plugging of rock cores with resuscitated starved bacteria. See text for details...

Figure 4. Scanning electron microscopy of starved (A) and nutrient stimulated (B) Klebsiella pneumoniae in sandstone rock cores. The bar represents 5 ym.

Around 85% of the total amount of hydrogen is present as a metallic phase. It is assumed that there is a silicate rock core with a temperature estimated to be... 

Samples of rocks, core samples, stream sediments, panned semi-concentrate and... 

Fig. 13. Rock core samples cut by a diamond-faced core bit reveal underlying structure and the possible presence of hydrocarbons, (Exxon Corp)...

These data, however, were collected early in the experiment (i e , after ten days) and are likely to be not representative of the steady-state condition of the system The steady-state composition of the second vessel outlet solution will be measured, when the rock core is taken off-line at the end of the experiment ... 

The actinide retardation data for the hydrothermally-altered repository component experiments (4 and 5) in Table VI are preliminary and their interpretation is hindered by the lack of attainment of a steady-state condition for actinide migration in the systems These data indicate that only a small fraction of the actinides are retained by the rock core Comparing these results to those of the unaltered fissure experiments, where Pu and Np were almost completely retarded by the rock core, one could conclude that altering the rock tends to lower its ability to retard actinide migration Another way to discuss these same data, and one that leads to a completely opposite conclusion, is in terms of the amount of activity retained by the rock core, or, the rate of actinide loss from the groundwater in terms of A (dpm/mL) of 2 Pu and 237Np ... 

Also, laboratory experiments will be run with rock cores containing naturally-aged fissures. This will be an important step in testing the appropriateness of laboratory aging of rock surfaces to simulate natural aging processes. 

A. J. Lucas, G. K. Pierens, M. Peyron, T. A. Carpenter, L. D. Hall, R. C. Stewart, D. W. Phelps, and G. F. Potter, Quantitative porosity mapping of reservoir rock cores by physically slice selected NMR, in P. F. Worthington and C. Chardaire-Riviere, (Eds.), Advances in Core Evaluation III Reservoir Management, Reviewed Proceedings of the Society of Core Analysts Third European Core Analysis Symposium, France, September 14—16, 1992, Gordon and Breach Science Publishers, Reading, UK, 1993, pp. 3-24. 

Although there has been considerable effort to calculate the mobility of foam in porous media from first principles, utilizing usually measured rock properties ( 6), a different approach is used here. In this research, major emphasis has been on measurement of the mobility of C02 foam in rock core samples. The... 

Most of the sorption experiments for rock materials have been performed using crushed rocks [3], and only a limited number of sorption studies were performed for rock coupons or rock cores [4]. The aims of this study are therefore to investigate the kinetics and reversibility of U(VI) sorption upon the natural fracture surfaces and fresh intact surfaces of a Korean granite rock, respectively, and to investigate which constituent mineral of the granite rock contributes to the sorption of U(VI). 

Figure 9 Comparison of silicate mass fractions. Two assumptions for interior strueture are shown (i) differentiated—rock core, ice mantle, and (ii) homogeneous—uniformly mixed ice and roek. Also shown are silicate mass fractions for the Jupiter and Saturn systems and expected values for two models of the early solar nebula carbon chemistry (see text) (after Johnson et aL, 1987) (reproduced by permission of Ameriean Geophysieal Union from /. Geophys. Res. Space Phys. 1987, 92, 14884-14894).

In situ (field) batch sorption tests use measurements of the radionuclide contents of samples of rock cores and consanguineous pore water obtained at a field site. The advantage of this approach is that the water and rock are likely to be... 

Samples of rock can only be obtained by coring , that is, by drilling into a rock mass with a hollow drill bit. Bits are available in many sizes, with the cutting edges made of tempered steel or of steel in which many tiny industrial diamonds are imbedded. The solid portions of the rock cores obtained are considered undisturbed , and representative of the properties of the in-situ rock. The makeup of a rock sample is a function of the relation between the sample size and the joint or fracture system, as shown in Figure 1.3. 

Flow and diffusion rock cores, chromatography columns, and complex fluids... 

Rock cores are examined in two different states. One is a preserved state where attempts are made to retain the original conditions of fluid saturation. This poses problems because the environment of the samples alters from high pressure and temperature to lower values when lifting the rock cores out of the drill hole to the earth s surface. The other approach uses cleaned cores which have been extracted with solvents to remove the reservoir fluids and impurities. These cores are subsequently resaturated with selected fluids to gain the desired measurement conditions. 

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