The interaction of the Sn-Cu-Co powder material with diamond in liquid-phase sintering has been studied. The material contained commercially pure metal powders at the following proportion, wt. %: 21 Sn, 46 Cu, 33 Co. Metal powders and synthetic diamonds AS150 were mixed with the organic binder and applied on a steel base. Sintering was performed in vacuum at 820–1100°C. The structure of sintered materials is investigated by X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray microanalysis. It has been found out that at sintering temperatures of over 900°C, the liquid phase wets and dissolves diamonds due to its containing cobalt. When the material is cooled down after sintering, the dissolved carbon crystallizes on the surface of diamonds in the form of graphite flakes, which leads to the formation of a weak layer between diamonds and the metallic matrix.

The effect of tungsten nanoparticles and microparticles on the structure and hardness of sintered Sn–Cu–Co–W alloys has been studied. Tungsten powder of 19–24 μm sized particles was milled in a planetary-centrifugal mill, after which the size of particles was 25 nm to 20 μm. The milled and non-milled tungsten was then mixed with powders of tin, copper and cobalt. The specimens were compacted in moulds and sintered in vacuum at 820°C for 20 minutes. The structure of sintered materials was studied using X-ray diffraction analysis and scanning electron microscopy. Microhardness (HV0.01) of structural constituents and hardness of the materials were measured. It has been determined that it is alloys containing mechanically milled tungsten that have the highest hardness. The main factor influencing the rise of hardness is dispersion hardening with nanoparticles. A further factor is work hardening of tungsten microparticles during ball milling. The highest hardness of 109–111 HRB has been obtained in the Sn–Cu–Co–W alloy containing 23% wt. of milled tungsten, with the proportion of tin, copper and cobalt being 1/2.6/1.6.

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TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractThe Maloichskoe field is located in the southeastern part of the West Siberian basin in Novosibirsk oblast (Fig. 1). It was the first field in the basin where commercial oil was produced from the Paleozoic basement. The reservoir consists mostly of limestones and dolomites that are intensively fractured and contain numerous vugs in some zones. The reservoir properties of the matrix are generally negligible, and the production potential of wells is mostly associated with natural fractures and vugs.The presented study was our first project in Russia where a complete integrated approach was implemented to properly characterize a fractured reservoir. The approach included the following tasks: 1) Identification of fractured intervals in wells using a special technique of BKZ logs processing, 2) Spectral imaging and high-resolution inversion of the seismic data, 3) structural analysis of the field, 4) construction of the reservoir properties model, 5) construction of the fracture distribution model using the Continuous Fracture Modeling approach (CFM).The final geologic model served as a basis to select the locations for the new wells. The new locations were proposed in the zones with the most intensive development of a network of natural fractures (according to the model). The drilling was associated with significant losses of drilling mud that was an indirect indication of presence of significantly fractured zones. The wellbore image FMS that was recorded in the well, showed a good level of correspondence between the model forecast and the actual result. The well contains interval of numerous fractures and large vugs. Eventually, the well showed a good production results and currently is one of the best producers in the field.As such, we recommend application of the described integrated approach for modeling complex fractured reservoirs in the other fields of Russian Federation.