Page 491 - Air and Gas Drilling Manual

10-16 Air and Gas Drilling Manual
.41
,595
80
554
22 11
)
(. ) ( , 1 827
,
(. 0 0659
, 4 275
.67
519
.
,
11 68 0 949 10 000) ln 80 595 4 275 ( 0 187) ) (10 000 )
,
(
.
,
.
The left and right sides of the above give, respectively,
112 112
.
.
Using Equation 4-11, the specific weight of the gas at bottomhole pressure and
temperature conditions is
(,595 ) ( . )
80
1
0
bh
(53 .36 ) (604 . )
41
.
250 lb/ft 3
bh
The volumetric flow rate of the gas at bottomhole pressure and temperature
conditions, Q gbh, is
w ˙ g
Q gbh
bh
1 456
.
Q gbh
250
.
3
Q gbh 0 583 ft /sec
.
The foam quality at the bottom of the annulus is
Q gbh
bh
Q gbh Q w
.
0 583
bh
0 583 0 187
.
.
.
076
bh
The above foam quality value is greater than 0.60. Therefore, the mixture of water,
surfactant, and gas (air) is a stable foam.