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Planning for Environmental Protection 161

The most important way to reduce the emission of volatile hydro-
carbons at production facilities is to install vapor recovery systems.
Casing vapor recovery systems should be in thermal recovery opera-
tions to collect casing gases. Recovery units can be installed to collect
glycol reboiler vapors (Choi and Spisak, 1993; Schievelbein, 1993).
Mercury manometers along gas flow lines can be replaced with elec-
tronic, digital flow meters

5.3.2 Material Reuse

Many of the materials in drilling and production waste streams can
be used more than once. If materials are intended for future use, they
are not wastes. The following materials have a potential for reuse:
acids, amines, antifreeze, batteries, catalysts, caustics, coolants, gases,
glycois, metals, oils, plastics, solvents, water, wax, and some hazard-
ous wastes.
Water has a considerable potential for reuse. For example, water
from reserves pits can be used to wash shale shakers and other solids
control equipment during drilling. Reserves pit water should also be
used as makeup water for drilling mud as much as possible. Water
from mud can be cleaned and used as rig washwater. Rig washwater
can be collected and reused, particularly at contractor facilities.
Lubrication and cooling water used by pumps can also be recycled.
Water obtained from dewatering a reserves pit could be treated and
used at another site, particularly in arid areas. Produced water, after
treatment, can be reinjected for pressure maintenance during water
floods or for steam injection in heavy oil recovery.
Material reuse can be facilitated by installing equipment that allows
reuse. For example, closed-loop systems can be installed so that
solvents and other materials can be collected and reused in plant
processes. Reusable lube oil filters can be installed in some applica-
tions instead of throwaway filters. Flared natural gas can be reinjected
for pressure control, or an alternate use for it can be found. Flaring
should be restricted to emergency conditions only.
Many drilling and production wastes could be used at other sites
or be returned to the vendor. For example, reconditioned drilling mud
could be reused for other wells, either by the operating company or
by the vendor. Waste rnud from one well can be used for plugging or
spudding other wells. Some used chemical containers can be returned