Method and software for numerical simulation of reservoir properties of oil- and gas-bearing rocks

5A 941030 Hydrochemistry and rock weathering in a sub-tropical Lesser Himalayan river basin in Kumann, India Bartarya, S K J Hydrol V146, N1/4, June 1993, P149-179 Major ion chemistry of waters of the Gaula catchment was measured at numerous sites in 1983 and 1984. Influence of rock weathering on the geochemistry of the ground and surface waters was studied. Catchment lithology contributes a large part of the major constituents of the waters. The low ionic concentrations relative to Indian peninsular rivers reflect the steep topography with rapid infiltration and quick outflow with short residence times for water-rock interaction. 941031 Recharge and weathering processes in fractured rock aquifers in Northern Australia Herczeg, A L; Payne, T E Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 V1, P561-564. Publ Rotterdam: A ,4 Balkema, 1992 Groundwater geochemistry in the vicinity of the Koongarra No 1 uranium orebody has been studied. These waters are dilute magnesium bicarbonate waters with TDS generally less than 150mg/l. Most of the dissolved constituents result from action of dissolved carbon dioxide on chlorites. Isotope studies suggest a connection between the recharge mechanism and weathering processes, with recharge through fractures along and across the Koongarra fault. As groundwater flows downgradient, it mixes with more dilute waters recharging vertically through the relatively unreactive weathered zone. 941032 Consequences of acid deposition on natural weathering processes: field studies and modelling Probst, A; Fritz, B; Stille, P Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 V1, P581-584. Publ Rotterdam: A A Balkema, 1992 Hydrochemical budgets obtained over a 4 year period in a small granite basin in the Vosges massif, France, indicate the influence of acid atmospheric input on chemical weathering rates. The soils are acidic, thus only weathering processes in the alterites effectively neutralise meteoric acidity. Important losses of calcium and silica substantiate this hypothesis. A geochemical model using Sr isotopes clearly demonstrates the role of feldspar dissolution in neutralising the incident acidity.

Properties of Rocks and Soils

and normalized values of natural factors are established on the basis of laboratory and field measurements. Terrigenous, carbonate, and shale materials can be handled. Porosity, permeability, and bulk density can be predicted. The methodology, required input parameters, and examples of numerical simulation are presented. The computer program used is listed.

941034 Anisotropy in pore networks analyzed with 2-D autocorrelation (variomaps) Frykman, P; Rogon, T A Comput Geosci V19, N7, Aug 1993, P887-930 A system is presented to generate variomaps (autocorrelation or variance as a topological map) of binary images. The images are produced from plane sections through porous materials and the 2D autocorrelation functions obtained via Fourier transformation. Mean pore size and anisotropy of the section are illustrated. The method has been tested on sandstones, simulated grain packs, and a catalyst material. Even large images can be processed in minutes on a PC using the Pascal software, which is listed.

941035 Fractal characteristics of rock discontinuities Ghosh, A; Daemen, J J K Engng Geol V34, N1/2, May 1993, P1-9 Detailed discontinuity data were obtained from photographs of four bench faces in an open pit copper mine. The theory of fractal geometry is applied to describe the rock fracture network. Three parameters characterise the visible discontinuities. The complexity of the network formed by individual discontinuities is measured by one parameter. Intensity and interconnectivity are characterised by fracture density and block density respectively. All three parameters show fractal distribution over the range investigated, suggesting that the rock fracture process may be a scale independent phenomenon.

941036 Evaluation of fill compaction. Technical note Sikh, T S Geotech Test J V16, N2, June 1993, P276-278 Field densities of existing fills at seven sites were evaluated using the sand-cone method (ASTM DI556), the drive-cylinder method (ASTM D2937), and a smaller version of the drive-cylinder, driven manually into the ground. Excellent correlation is seen between sand-cone values and those from the other two methods.

Composition, structure texture and density See also: 941007, 941009 941033 Method and software for numerical simulation of reservoir properties of oil- and gas-bearing rocks Buryakovsky, L A Comput Geosci V19, N6, July 1993, P803-815 A mathematical model has been developed for prediction of reservoir and physical properties of sedimentary rocks, which considers the many natural factors causing postsedimentational changes and consolidation. Relations between absolute

941037 Picture processing applied to minerals: example of a quantitative analysis of feldspars in rocks (In French) Lacube, J; Bissainte, M; Hernandez, J Int Assoe Engng Geol Bull N47, April 1993, P109-117 Image analysis using the OPTILAB package has been applied for quantitative morphological analysis of plagioclase crystals in volcanic rocks from Guadeloupe. Digitized images from a scanner were fed to OPTILAB which had been optimized to determine only plagioclase. Crystal size distributions were obtained plus a quantitative signature of the geological formation.