Page 338 - Shale Shakers Drilling Fluid Systems

320 SHALE SHAKERS AND DRILLING FLUID SYSTEMS

offered to the passage of a current, expressed in ohm-meters. The recip-
rocal of conductivity. Freshwater muds are usually characterized by high
resistivity and saltwater muds by a low resistivity. See.- Conductivity.

Resistivity Meter An instrument for measuring the electrical resistivity of drilling fluids.

Retention Time The time any given particle of material is retained in a region; for ex-
ample, the time a particle is actually on a screening surface, within a
hydroclone or the bowl of a centrifuge.

Retort An instrument used to distill oil, water, and other volatile material in a
drilling fluid to determine oil, water, salt and total solids contents in
volume-percent. See: Mud Still, Mini Still, API Bulletin RP 13B.

Reverse Circulation The method by which the normal flow of a drilling fluid is reversed
by circulating down the annulus, then up and out the drill string. See:
Circulation.

Reynolds Number A dimensionless number, R e, that occurs in the theory of fluid dynamics.
Reynolds number for a fluid flowing through a cylindrical conductor is
determined by the equation: R e = DVp/u; where diameter = D; velocity =
V; density = p, and viscosity = p. The number is important in fluid hy-
draulics calculations for determining the type of fluid flow (i.e., whether
laminar or turbulent). The transitional range occurs approximately from
2,000 to 3,000. Below 2,000 the flow is laminar and above 3,000 the flow
is turbulent. See.- Fluid Flow.
Rheology The science that deals with deformation and flow of matter. See.- Viscos-
ity, Bingham Model, Plastic Viscosity, Yield Point, Gel Strength.

Rig Pump The reciprocating, positive displacement, high-pressure pump on a drill-
ing rig used to circulate the hole. See: Mud Pump.

Rig Shaker A slang term for a shale shaker.
Rigid Frame Panel One of the two main screen panel types that consists of a rigid panel to
which the screen or layers of screen are attached. The screen panel fas-
tening device can be designed for fast panel replacement. See.- Hookstrip
Panel.

ROP See/ Rate of Penetration, Penetration Rate.

Rope Discharge The characteristic underflow of a hydrocyclone so overloaded with sepa-
rable solids that not all separated solids can travel out the underflow open-
ing (apex). This causes the solids that can exit to form a slow moving, heavy,
rope-like stream. Also referred to as "rope" or "rope underflow."
Rotary Drilling The method of drilling wells in which a drill bit, attached to a drill string,
is rotated on the formation to be drilled. A fluid is circulated through the
drill pipe to remove cuttings from the bottom of the hole, bring cuttings
to the suface, and perform other functions. See.- Cable Tool Drilling.

Rotary Mud Separator A centrifuge consisting of a perforated cylinder rotating inside an outer
cylinder housing. As drilling fluid flows outside of the perforated cylin-
der, only the very small particles pass through the perforations.

RMS See: Rotary Mud Separator.