Page 313 - Shale Shakers Drilling Fluid Systems

GLOSSARY 295

Drilling Out The operation of drilling the casing shoe after the cementing a casing or
liner in place. Drilling out of the casing is required before a bore hole
is deepened.

Drilling Rate The rate at which hole depth progresses, expressed in linear units per
unit of time (including connections) as feet/minute or feet/hour. See.- ROP,
Rate of Penetration, Penetration Rate.

Dry Bottom An adjustment to the underflow opening of a hydrocyclone that causes
a dry beach, usually resulting in severe plugging. See.- Dry Plug.

Dry Plug The plugging of the underflow opening of a hydrocyclone caused by
operating with a dry bottom. See: Dry Bottom.

Dryer A shale shaker with a fine mesh screen that removes excess fluid and
fine solids from discarded material from other shale shakers and hydro-
cyclones. Typically, this is used to decrease the liquid waste from a drill-
ing fluid to reduce discarded volumes. See: Mud Cleaner.

Dryer Shaker See.- Dryer.

Dual Wound Motors Motors that may be connected to either of two voltages and starter
configurations.

Dynamic The state of being active, or in motion, as opposed to static.

ECD See.- Equivalent Circulating Density, Annular Pressure Loss.

Eductor (1) A device consisting of a fluid stream discharging under high pressure
from a jet through an annular space to create a vacuum. When properly
arranged, it can evacuate degassed drilling fluid from a vacuum-type
degasser. (2) A device using a high velocity jet to create a vacuum that
draws in liquid or dry material to be blended with the drilling fluid.

Effective Screening Area The portion of a screen surface available for solids separation.

Effluent A discharge of liquid. Generally, used to describe a stream of liquid after
some attempt at separation or purification has been made. See: Discharge.

Elastomer Any rubber or rubber-like material (such as polyurethane).

Electric Logging Logs run on a wire line to obtain information concerning the porosity, per-
meability density, and/or fluid content of the formations drilled. The drill-
ing fluid characteristics may need to be altered to obtain satisfactory logs.

Electrolyte A substance that dissociates into charged positive and negative ions when
in solution or a fused state. This electrolyte will then conduct an electric
current. Acids, bases, and salts are common electrolytes.

Elevation Head The pressure created by a given height of fluid. See: Hydrostatic Pressure
Head.

Emulsifier A substance used to combine two liquids that do not solubilize in each
other or maintain a stable mixture when agitated in the presence of each
other. Emulsifiers may be divided, according to their behavior, into ionic
and nonionic agents. The ionic types may be further divided into anionic,
cationic, and amphoteric, depending on the nature of the ionic groups.