CUTTINGS SLIP VELOCITY

Particle Slip Velocity In Circulating Mud

INPUT   DATA

Title  

Mud weight ppg
Plastic viscosity cps
Yield point lb/100ft2
Hole diameter in
Drill pipe OD in
Density of particle ppg
Diameter of particle in
Circulation rate gpm

     Reset

OUTPUT   VARIABLES   &   GRAPHS

Velocities  (ft/min.)
 ♦  Annular
 ♦  Cutting Slip
 ♦  Net Cutting rise
THEORY  &   FORMULAE

Particle Slip Velocity

This term is generally used to refer to the difference between the average fluid velocity and the average cuttings velocity, measured in the axial direction of the pipe/wellbore, irrespective of whether it is vertical, deviated or horizontal.

The particle slip velocity of a cutting of a specific size in a given fluid is estimated here according to Moore's correlation , a correlation which has achieved widespread acceptance in the oil industry. It provides insight for the selection of appropriate pump operating conditions and drilling fluid properties that will optimize the transportation of drill cuttings to the surface. The associated annular velocity and net cuttings rise velocity are also calculated, and the sensitivity of slip velocity to pump rate is plotted.

The relevant equations are:

        

Where:

   Vs = slip velocity, ft/min.
   v = annular velocity, ft/min
   ρm = mud weight, ppg
   ρp = particle density, ppg
   φp = particle diameter, in.
   n = derived parameter of mud, dimensionless
   K = derived parameter of mud, dimensionless
   θ300 = 300 viscometer dial reading
   θ600 = 600 viscometer dial reading
   θ300 = PV + YP
   θ600 = θ300 + PV
   PV = plastic viscosity of mud, cps
   YP = yield point of mud, lb/100ft2
   Dh = hole diameter, inches
   Dp = drill pipe OD, inches

BIBLIOGRAPHY