Page 219 - Well Control for Completions and Interventions

212 Well Control for Completions and Interventions

Moreover, there is some evidence to suggest some of the resin will liquefy
when in contact with formation oil and invade the formation, causing
damage. Because of these problems, oil soluble resins are not in wide-
spread use.

5.9.4 Mechanical fluid loss control
The use of one or more mechanical barriers can be hugely beneficial dur-
ing workover and completion operations. With a tested mechanical bar-
rier, the risk of a kick, or of fluid loss leading to a kick, is significantly
lower. In addition, a mechanical barrier can eliminate the need to place
potentially damaging fluid in direct contact with the reservoir.
The use of mechanical barriers is largely dependent on the design of
completion and the requirements of the workover.
The only disadvantage to using a mechanical fluid barrier is the
potential for a difficult recovery operation, particularly if debris is allowed
to settle on top of the plug. The use of debris catchers and proper clean-
ing of the wellbore will reduce the risk of a stuck plug.

5.10 HOW MUCH BRINE IS NEEDED?

Where brine has a well control function, it is important that
enough brine is available at the wellsite to enable completion or workover
operations to continue without interruption. The potential for brine to
be lost must also be factored into any volume calculations. The volume of
brine at the wellsite will be determined mainly by the wellbore capacity
or circulating volume. The circulating volume must include any surface
piping and throughput capacity of filtration equipment (if used). In addi-
tion to the circulating capacity, there should be enough brine at the well-
site to cover contingencies, principally losses.

5.10.1 Wellbore capacity
Wellbore or circulating volume are easily calculated. Casing or tubing
volume can be looked up using widely available tables in publications
such as “Baker Tech Facts” or the “Halliburton Red Book.” Casing and
tubing capacity data is also available on line, and there are now plenty of
“Apps” that have tubing and casing capacity data. Alternatively, simple