STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

832 Drilling and Well Completions
For a Power law fluid flow, the following formulas can be used:
Pipe flow
(1.6~ 3n + 1)" ( 30y)
pL,= d4n -
(4-96)
Annular flow
2.4~ 2n+l
pe=(d,-d,sn)'
200K(d, -d2)
v
(4-97)
The mud rheological properties pLp, z , n and K are typically calculated based
upon the data from two (or more)-speed rotational viscometer experiments. For
these experiments, the following equations are applicable:
PLp = e,,, - %oo(cp)
zY = 8,,, - pp(lb/lOO ft')
(4-98)
(4-99)
e600
n = 3.32 log -
e,,,
K = ( lb/10Oft2s-" )
(511)"
(4-1 00)
(4-101)
where e,,, = viscometer reading at 600 rpm
B, = viscometer reading at 300 rpm
Example
Consider a well with the following geometric and operational data:
Casing 9Q in., unit weight = 40 lb/ft, ID = 8.835 in. Drill pipe: 44 in., unit
weight = 16.6 lb/ft, ID = 3.826 in. Drill collars: 6$ in., unit weight = 108 lb/ft,
ID = 23 in. Hole size: 8+ in. Drilling fluid properties: O, = 68, 8,,, = 41,
density = 10 lb/gal, circulating rate = 280 gpm.
Calculate Reynolds number for the fluid (1) inside drill pipe, (2) inside drill
collars, (3) in drill collar annulus, and (4) in drill pipe annulus.
To perform calculation, a Power law fluid is assumed.
Flow behavior index (use Equation 4-100) is
68
n = 3.32log- = 0.729
41
Consistency index (use Equation 4-101) is
K=-- 41 - 0. 4331b/100ft2s".729
( 5 1 1)o. 729