دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: finely crystalline, generally lightcoloured extrusive igneous rock com- posed largely of plagioclase feldspar with smaller amounts of dark-coloured minerals. Compare diorite.

n: sandstone composed largely of feldspar grains and deriving from granitic source rocks.

A sandstone containing 25% or more of feldspar, usually derived from igneous rock.

n: I. a term used for particles smaller than \1156 millimetre (4 microns) in size, regardless of mineral composition. 2. a group of hydrous aluminum silicate minerals (clay minerals). 3. a sediment of fine clastics.

n: (1) A soft, variously colored earth, commonly hydrous silicates of alumina, formed by the decomposition of feldspar and other aluminum silicates. Clay minerals are essentially insoluble in water but disperse under hydration, grinding, or velocity effects.

a fine grain (<0.00015” or about 4 microns) – finely crystalline silica sheet minerals. Usually of silicate composition. In oil field terms, the most common clays are Smectite (montmorillinite),illite, kaolinite and chlorite. The characteristic for autho

n: intrusive. or platonic. generally coarse-grained igneous rock composed largely of plagioclase feldspar with smaller amounts of dark-colored minerals. Also known as black granite. Compare andesite.

n: a group of silicate minerals that includes a wide variety of potassium, sodium, and aluminium silicates. Feldspar makes up about 60 percent of the outer 9.3 miles (15 kilometres) of the earths crust.

a silicate mineral, often modified and sometimes part of the movable particles in a formation.

adj: containing or largely composed of feldspar or feldspar grains.

n: an igneous rock composed primarily of feldspar, quartz. and mica. It is the most common intrusive rock - that is, it originally solidified below the surface of the earth. Its rock crystals are easily seen by the eye.

common igneous rock. No effective permeability.

n: a sandstone that contains more than 15 percent silt and clay. and whose grains tend to be angular and poorly sorted.

a sandstone, characterized by angular-shaped grains of quartz and feldspar set in a matrix of fine grains. May have high hardness.

n: A group of clay minerals formed during the alteration of silicate minerals such as mica and feldspar and commonly found in marine shales.

a clay type of varying form and composition. Rarely water sensitive. May occur in unusual cases as a fiberous deposit that can act as a particle trap.

n: a light-coloured feldspar mineral (KA1Si3O8),common in granite.