دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a large, sloping sedimentary deposit at the mouth of a canyon, laid down by intermittently flowing water, especially in arid climates, and composed of gravel and sand. The deposit tends to be coarse and unworked, with angular, poorly sorted grains in thin, overlapping sheets. A line of fans may eventually coalesce into an apron that grows broader and higher as the slopes above are eroded away.

land counterpart of a river delta. Characteristic of sediments that have been transported by a fast moving stream then dropped out of the flow as the stream velocity drops as it spreads out. Typical of zones of heavy water runoff such as found at the base

n: a deviation from the norm. In geology the term indicates an abnormality such as a fault or dome in a sedimentary bed.

n: igneous or metamorphic rock, which seldom contains petroleum. Ordinarily, it lies below sedimentary rock. When it is encountered in drilling, the well is usually abandoned.

unproductive rocks, usually igneous or metamorphic, at the bottom of a sedimentary rock sequence.

n: (BS&W) see sediment and water (S& W). form thick sequences of sedimentary rock. 2. the area drained by a stream and its tributaries. 3. a geologii: structure in which strata are inclined toward a common centre.

rocks such as coal resulting from decomposition of animal or plant deposition.

n: an elevation on an ancient land surface that is covered by younger sedimentary rocks.

n: a sedimentary rock composed primarily of calcium carbonate (calcite) or calcium magnesium carbonate (dolomite).

n: A kind of sedimentary rock whose content of carbonate is over 50%. Mainly consisted of calcite, dolomite and ankerite.

n: I. the crystallisation or precipitation of soluble minerals in the pore spaces between clastic particles, causing them to become consolidated into sedimentary rock. 2. precipitation of a binding material around grains or minerals in rocks.

the material in the rock between the grains that binds the grains together.

n: a rock of precipitated silica whose crystalline structure is not easily discemible and that fractures conchoidally (like glass). Flint, jasper, and chat are forms of chert.

a hard, silicate sedimentary rock. Similar to flint, but with less ordered structure. A cryptocrystalline form of quartz.