Page 207 - Well Control for Completions and Interventions

200 Well Control for Completions and Interventions

bromide are extremely hazardous, with the potential to blind and cause
painful reddening and blistering of the skin similar to a burn.
Material Safety Data Sheets should be available for any brine, as well
as brine additives that will be used at the wellsite. Moreover, personnel
should be properly briefed on any risks associated with mixing, storing,
and pumping brine. Where appropriate, personal protective equipment
should be used to prevent exposure. Should exposure to harmful brine
occur, it must be dealt with immediately. Skin contact should be treated
with prolonged washing with freshwater, and eye contact with eye wash
solution, or if none is available, prolonged washing with freshwater.
Brines are harmful to the environment. While some of the brine salts
can be diluted to render them harmless, brine containing zinc bromide
cannot. Indeed, in some jurisdictions the use of brine containing zinc
bromide is discouraged.

5.6 BRINE COMPATIBILITY

The well control function of brine determines brine density, and
crystallization temperature is related to brine density. The next step is to
consider brine compatibility with the formation, formation fluids, and
the completion materials. While brine incompatibility with the formation
can have a detrimental effect on productivity, an incompatibility with the
completion materials (metals and elastomers) can have a direct effect on
well integrity. Poor brine selection can lead to accelerated corrosion pro-
blems in metal components and failure of elastomers. Compatibility can
only be established through testing. Some of the tests can take many
weeks, even months, to complete so changes to proven brine formula-
tions should not be undertaken lightly.

5.6.1 Fluid compatibility with completion materials (metals)

Dissolving salt such as potassium chloride and sodium chloride in water
will increase corrosion rates, since the brine becomes more ionic, relative
to freshwater. However, some high density brines will become less corro-
sive, as the high concentration of salt reduces oxygen solubility. For
example, corrosion in a sodium chloride solution peaks when the chlo-
ride concentration is approximately that of seawater, 20,000 mg/L.