دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

unconsolidated to well sorted to poorly sorted (gravel to sand sized) particles transported by water.

an empirical relationship between the formation resistivity, F, and porosity, , in which F=1/m, where the porosity exponent or cementing factor, m, is a constant for a particular formation. Typical m’s are 1.8 to 2.0 for consolidated sandstones and 1.3

v: 1. to collect a mass of sticky consolidated material, usually drill cuttings, on drill pipe, drill collars, bits, and so forth. A bit with such material attached to it is called a balled-up bit. Balling up is frequently the result of inadequate pump pressure or insufficient drilling fluid. 2. in reference to an anchor, to fail to hold on a soft bottom, pulling out, instead, with a large ball of mud attached.

n: The phenomenon that drill bit or drill tool is surrounded by cutting and viscous mud in drilling progress.

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: 1. see conductor casing.2. a boot, or flume.

n: A short string of large-diameter casing set to support the surface formations. The conductor pipe is typically set soon after drilling has commenced since the unconsolidated shallow formations can quickly wash out or cave in. Where loose surface soil exis

the first string of casing run, usually to keep rocks or dirt out of the wellbore. It is usually not cemented in place. It may be jetted in, driven in, drilled in or installed in an excavated hole.

an approximate level of rock strength where sufficient cementation is present to allow the rock to remain intact during drilling and production. Often the unconfined compressive strength is greater than 1000 to 1500 psi.

the sonic travel time in microseconds per foot, of a sound wave through the formation. Denser formations (generally better consolidated and cemented) have lower (faster) delta t times.

the ability of a rock to expand through micro-fractures in consolidated rocks or grain position shifts in unconsolidated rocks.

n: a sudden increase in the drill bits rate of penetration. It sometimes indicates that the bit has penetrated a highpressure zone and thus warns of the possibility of a kick.

n: a phenomenon of the drilling speed abrupt changes when the formation characteristics

change

a sudden increase in the ROP (rate of penetration) while drilling. May indicate a higher pressure formation, a change in lithology, a naturally fractured zone, or a poorly consolidated zone.

add sufficient fluid in an unconsolidated sand matrix to break cohesive bonds and lubricate grain by grain movement of sands.