Page 316 - Shale Shakers Drilling Fluid Systems

298 SHALE SHAKERS AND DRILLING FLUID SYSTEMS

(2) The solid residue deposited on the wall of a borehole during the drill-
ing of permeable formations. See.- Wall Cake.
Filter Cake Thickness See.- Cake Thickness.

Filter Press A device for determining the fluid loss of a drilling fluid having specifi-
cations in accordance with API Bulletin RP 13B. See.- API Bulletin RP 13B.

Filter Run The interval between two successive backwashing operations of a filter.

Filterability The characteristic of a clear fluid that denotes both the ease of filtration
and the ability to remove solids while filtering.

Filtrate Loss See: Fluid Loss.
Filtration (1) The separation process of suspended solids from liquid by forcing the
liquid through a porous medium while screening back the solids. Two
types of fluid filtration occur in a well: dynamic filtration while circulat-
ing, and static filtration when the fluid is at rest. (2) The process of drill-
ing fluid losing a portion of the liquid phase to the surrounding forma-
tion. See: Water Loss.

Filtration Rate See.- Fluid Loss.

Fine Screen Shaker A vibrating screening device designed for screening drilling fluids through
screen cloth finer than 80 mesh.
Fine Screen Shale Shakers Usually refers to shale shakers that vibrate screens with a balanced el-
liptical or linear motion. These are usually capable of processing large
flow rates of drilling fluid through 120- to 250-mesh screens.
Fine Solids Solids 44-74 microns in diameter or sieve size 325-200 mesh. See: API
Bulletin RP 13C.

Fishing Rig operations for the purpose of retrieving sections of pipe, collars, or
other obstructive items that are in the hole and would interfere with drill-
ing or logging operations.

Flat Decked Shaker screens that do not have a crowned, or bowed, surface.

Flat Gel A condition wherein the gel strength does not increase appreciably with
time and is essentially equal to the initial gel strength. Opposite of pro-
gressive gel. See: Progressive Gel, Zero-Zero Gel.

Flight On a decanting centrifuge, one full turn of a spiral helix such as a flute
or blade of a screw-type conveyor. See: Blade, Flute.

Flipped A slang term for an extreme imbalance in a drilling fluid. In a water-in-oil
emulsion, the emulsion is identified as "flipped" when the continuous and
dispersed phases separate and the solids begin to settle.
Floe Small gelatinous masses of solids formed in a liquid.

Flocculates A group of aggregates or particles in a suspension formed by electrostatic
attraction forces between negative and positive charges. Bentonite clay
particles have negatively charged surfaces that will attract positive
charges such as those of other bentonite positive-edge charges.