Page 174 - Environmental Control in Petroleum Engineering

160 Environmental Control in Petroleum Engineering

operated and maintained. Inefficient equipment should be replaced with
newer, more efficient equipment.
One of the first steps to be taken is to eliminate all leaks and spills from
equipment. Drip pans can be used beneath the drilling rig floor to catch
all water or mud drained from it. Flexible hoses can be used to drain water to
or from the cellar. Leaking stuffing box seals should be replaced or new
stuffing boxes installed. Fugitive emissions from leaking valves, flanges,
and such fittings can be minimized by replacing leaking equipment.
If the interval between lube oil changes on diesel engines is lengthened,
the volume of waste lube oil can be reduced. The interval recom-
mended by manufacturers is normally based on "worst case" conditions
operations. By monitoring the quality of the lube oil over time and
using a higher quality lube oil, it may be possible to increase the time
between changes without any loss of engine protection. This could
significantly reduce the total amount of lube oil used (Reller, 1993).
Internal combustion engines should be properly tuned and the proper
fuel should be used. The emission of partially burned hydrocarbons
can be minimized by control of the fuel/air ratio during combustion.
The formation of SO x during combustion can be minimized by using
a low sulfur fuel such as natural gas.
If the volume of waste generated cannot be sufficiently reduced with
the existing equipment, newer equipment should be installed. Important
environmental features of newer equipment should be how easy they
are to monitor and clean up, as well as how they facilitate waste
recovery and recycling. New equipment should have modern emission
controls. In some cases, equipment with automated process controls
can be installed to ensure optimal operations.
Automatic shutoff nozzles and low-volume, high-pressure nozzles
should be installed on all hoses on the rig floor and wash racks to
minimize wastewater. Water meters should be installed on all fresh-
water sources to monitor and control water usage. Rig wash should
be limited to only the minimum needed for safety, not for esthetics.
More efficient separations equipment should be used to separate
solids, hydrocarbons, and water. Newer shale shakers can be used that
are better at filtering out small solids than older equipment. Low shear
pumps should be used for produced water to prevent hydrocarbon
droplets from decreasing in size, because small droplets are more
difficult to remove. Improved backwash equipment and better pro-
cedures can be used to extend filter life.