STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

862 Drilling and Well Completions
Equation 4-122 becomes
2.003 x lo-'( 2400)'
= ([(1694.7)' + 170.62(547.6)*]e'a~o~w54'~6 - 170.62(547.6)4}0'5
Equation 4-123 becomes (with k = KP)
a = 0.0187617 + 0.00014349Kp
From the above two equations the potential drilling rate K, for a Q = 2,400
actual cfm is found to be
K, = 103.3 ft/hr
Substitution of the above into Equation 4-137 yields
9, = -(-)
' 8'75 '(103.3-60) (62*4)(2'7) = 365.7 gal/hr
4 12
8.33
The total volumetric flowrate of foaming agent that s--ould be injectel
the circulating air is
into
q, I 0.06 + 0.002(365.7)
I 0.80 gal/hr
DOWNHOLE MOTORS
Background
In 1873, an American, C. G. Cross, was issued the first patent related to a
downhole turbine motor for rotating the drill bit at the bottom of a drillstring
with hydraulic power [78]. This drilling concept was conceived nearly 30 years
before rotary drilling was introduced in oil well drilling. Thus the concept of
using a downhole motor to rotate or otherwise drive a drill bit at the bottom
of a fluid conveying conduit in a deep borehole is not new.
The first practical applications of the downhole motor concept came in 1924
when engineers in the United States and the Soviet Union began to design, fabricate
and field test both singlestage and multistage downhole turbine motors [79]. Efforts
continued in the United States, the Soviet Union and elsewhere in Europe to develop
an industrially reliable downhole turbine motor that would operate on drilling mud.
But during the decade to follow, all efforts proved unsuccessful.
In 1934 in the Soviet Union a renewed effort was initiated to develop a
multistage downhole turbine motor [79-811. This new effort was successful. This
development effort marked the beginning of industrial use of the downhole
turbine motor. The Soviet Union continued the development of the downhole
turbine motor and utilized the technology to drill the majority of its oil and
gas wells. By the 1950s the Soviet Union was drilling nearly 80% of their wells
with the downhole turbine motors using surface pumped drilling mud or
freshwater as the activating hydraulic power.