Elements of rock mechanics in reservoir engineering

Elements of rock mechanics in reservoir engineering

PROPERTIESGENERAL Element procedure together with a quasi-Newton optimixation algorithm. Applying that scheme, various scenarios of oil migration in t...

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PROPERTIESGENERAL Element procedure together with a quasi-Newton optimixation algorithm. Applying that scheme, various scenarios of oil migration in the unsaturated and the capillary zone were simulated. Some migration characteristics predicted by the numerical simulations are discussed. (from Authors) 968081 Modelisatlon d’un aquifere basaltique fracture tenant compte de donnees geologiques, climatiques et hydrauliques: cas des basalt- perches de Garni (Armenie) (Modelling of a fractured basaltic aquifer with respect to geologkal setting, and climatic and bydraulk conditions: the case of perched basalts at Gami, Armenia) V. Leonardi, F. Arthaud, J. C. Grillot, V. Avetissian & P. Bochnaghian, Journal of Hydrology, 179(1-4). 1996, pp 87109. The underground water flow in volcanic rocks of a continental seismic area analysed using three approaches: 1) the structure of the basaltic reservoir; 2) the features of the hydrogeological domains involved and their structural limits; 3) the hydraulic behaviour of the system. According to these data, and without piexometric data, it is possible to compute circulation in the basaltic reservoirs according to the diffusivity equation. The good fit is obtained between these computed and measured values. (from English summary) 968082 An integration of geophysical methods and geocbemical analysis to map acid mine drainage - a case study tilK4,enson, Exploration & Mining Geology, 4(4), 1995, pp . Discharge waters from 88 sites in the central Wasatch Range, Utah have been evaluated over a 1060 km* study area. Generally, these groundwater systems have Ca*’ and HCOj as principal ions; many samples have Mgx+ and SOi- as abundant secondary ions. In the study area, mine drainage waters were collected from 14 mine-ad& openings, and at these sites. 613C and 6% comnositions were used to identifv the controlling factors of acid-mine drainage (AMD). (from Author)

PROPERTIES SOILS

OF ROCKS AND

General 968083 Elements de mecanique des roches en ingenierie de reservoir (Elements of rock mecbanks in reservoir engineering) y+f5yeca & J.-P. Sarda, Houille Blanche, 51(3), 1996, pp This document describes the elements of rocks mechanics which are useful to reservoir specialists. Initially poromechanits is presented; this science enables distortions of rock to be related to pressure variations, and by this way to flow equations. The notion of effective strain is clearly expressed and measures taken by laboratories are introduced. The consequences at the production level (compressibility) and at the environment level (surface subsidence) illustrate this notion. Stimulation by hydraulic fracturing is also presented. After a brief chronological account, the sources of modelling are defined and its implementation presented. (from English summary) 968084 Artificial surrogates: should tbey be used to provide data for precision statements for rock-property test metbods? H. J. Pincus, ASTM Stanabrdization News, 24(3), 1996, pp 28-32. While developing precision statements (repeatability and reproducibility) for several widely used test methods the ASTM Standards committee proposed using artilicial material. This material would avoid the problems of heterogeneity

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and anisotropy inherent in rock samples. The resulting precision statements, it was argued, would then reflect only the variability in the test methods and remain unaffected by the variability of the test material. The author’s conclusion, after studying test data from rock and artificial materials, is; artificial surrogates should not replace rock in developing precision statements for rock property test methods. The use of rock provides real world linkage for the precision statements. However, artificial surrogates, if available, should be used in addition to rock to provide data for such precision statements. (S.E.Long) 968085 Metal extraction by bacterial oxidation T. Brewis, Mining Magazine, 173(4), 1995, pp 197-207. This article presents an overview of bacterial oxidation processes and their application to metals extraction. The five general commercial scale methods of bacterial oxidation are briefly described. These are: agitated tank (or stirred reactor) leaching, heap leaching, vat leaching, dump leaching, and in situ leaching. The article focuses on the first two processes (stirring reactor processes these are: the BIOXR, BacTech, MINBACTM, and BioNICR processes. For heap leaching processes these are: Newmont’s bioleach, process and a two stage process being used at the Mt. Leyshon Gold Mine in Australia. The article also outlines several books and forthcoming conferences on this subject. (J.M.McLaughlin) 968086 Selection and test of effective chelators for removal of heavy metals from contaminated soils Ting-Chien Chen, E. Macauley & A. Hong, Canadian Journal of Civil Engineering, 22(6), 1995, pp 1185-l 197. Heavy metal contamination of soil is a common problem at many hazardous waste sites. Chelating extraction of heavy metals has been proposed as a remediation technique for contaminated soils. A useful method was developed, which assessed 190 ligands for their ability in extraction and recovery of target metals, including cadmium, copper, lead, mercury, nickel, and zinc. Chelator performance was evaluated based on equilibrium calculations with an emphasis on the potential of xecoverying both the metals and chelating agents. Batch equilibration experiments over 24-h periods were performed to test three chelating agents. All three chelators demonstrated high extraction capability toward their respective target metals across a wide range of pH, metal, and ligand concentrations. In addition, all three chelators exhibited good recovery potential at moderately elevated pH values. (from Authors) 968087 A mathematical model for tbe electrokinetic remediatioo of contaminated soil Y. S. Choi & R. Lui, Journal of Hazardous Materials, 44(l), 1995, pp 61-75. Describes a mathematical model for the electrokinetic remediation of contaminated soil. Assumes that the contaminants are mostly heavy metals, water is in excess, the dissociation-association of water into hydrogen and hydroxyl ions is rapid, and that electroosmosis is insignificant when compared to electromigration as a transport mechanism. Steady-state solutions for the model are derived and results of the numerical simulations are given to show that heavy metals in the soil are removed by this method in the long run. (Authors) 968088 Evaluation of soil washing process to remove mixed contaminants from a sandy loam R. Semer & K. R. Reddy, Journal of Hazardous Materials, 45(l), 1996, pp 45-57. Soil washing is a remediation process which is primarily used to treat soils and sludges which are contaminated with only one or two groups of contaminants. has not been extensively employed

This process, however, on soils that are wn-