Page 42 - Well Control for Completions and Interventions

34 Well Control for Completions and Interventions

operations are carried out with overbalanced (kill) fluid in the well. Kill
weight fluid is normally designed to provide 200 300 psi (1379 kPa)
overbalance. Insufficient overbalance will result in a kick. On the other
hand, too much overbalance can result in fluid loss to the formation,
resulting in a loss of overbalance and a kick.
Most interventions are carried out on underbalanced (live) wells,
where surface equipment, such as a wireline lubricator, is used to contain
the pressure.

1.1.8 Tubing and casing volume and capacity
Tubing, casing, and annular volume can be looked up in tables or calcu-
lated. To calculate pipe capacity all that is needed is the ID. To calculate the
annulus capacity, the pipe OD and casing ID is needed. Capacity 3 depth
gives the volume of a tubing string or annulus.

1.1.8.1 Using tables
A simple way of calculating tubing, casing, or annular volume is to use
one of the many readily available paper or electronic tables, such as
c
the Baker “Tech Facts” book, Halliburton’s “Red Book”, and the
Schlumberger digital i-handbook.
Tables provide the capacity of industry standard sizes for open hole,
drill-pipe, tubing, casing, and annulus. For example, the widely used
“Baker Tech Facts” book displays casing data using four different measures
of capacity. When working with oilfield units, the most frequently used
measure of capacity is barrels per linear foot (bbl/ft). Linear feet per barrel
is the reciprocal 1 of barrels per linear foot, for example for 5 /2v 17 lb/ft
1
x
tubing: 1/0.02324 5 43.01 bbls.
Example: Using Table 1.7, find the volume of fluid needed to fill
1
5000 ft of 5 /2v 17 lb/ft tubing.
5000 ft 3 0:9764 5 4882 US gallons
5000 ft 3 0:1305 5 652:5ft 3
5000 ft 3 0:02324 5 116:2 bbls:

c
Halliburton’s Red Book is available as an App. Download from their website or from
iTunes.