Page 156 - Shale Shakers Drilling Fluid Systems

CHAPTE R SEVE N

Solids Control Equipment

Adequate solids control should be instituted at and centrifugal pumps, are integral parts of a drill-
the beginning of any drilling operation due to the ing rig. Regardless of the drilling fluid system used,
detrimental effects of drilled solids discussed in certain fundamental tank arrangements are com-
earlier chapters. Drilled solids will erode, disperse, mon to all types of drilling fluid. Drilling engineers
and subdivide into smaller and smaller sizes as must make certain the arrangements are correct
they recirculate in the system. Smaller drilled sol- and decide what additional equipment is needed
ids create many problems and are increasingly for specific locations.
more difficult to remove. Once this process begins, Some of the standard principles for proper sol-
it is impossible to eliminate the solids unless a ids control are presented in this chapter and in-
large quantity of drilling fluid is jettisoned from the clude pit arrangements, piping, pumps, equipment
system and clean drilling fluid is introduced. arrangements, and sizing. The drilling fluid type
Proper drilled solids management has many (fresh water-base, saline water-base, oil-base,
beneficial effects on drilling operations: or synthetic), drilling fluid density (weighted or
unweighted), drill bit types, formation reactivity,
• Increased penetration rates and disposal costs will dictate additional specific
• Decreased drilling fluid costs
solids control equipment and procedures needed
• Reduced water (or oil) requirements
to assure the lowest well cost.
• Lower torque and drag Attention to details such as agitation, proper
• Reduced differential sticking problems centrifugal pump and impeller selection, proper
• Reduced pressure losses in the circulating system
plumbing for drilling fluid in the tank system,
• Lower equivalent circulating densities minimization of piping manifolds, and elimination
• Reduced lost circulation tendencies of leaks through valves will significantly improve
• Improved primary cementing operations overall solids removal and accrue substantial eco-
• Less remedial cementing nomic benefits.
• Less waste or disposal volumes
The purpose of a drilling rig surface fluid pro-
Drilled solids are separated from the drilling cessing system is to provide a sufficient volume of
fluid with a variety of different types of equipment. properly treated drilling fluid for drilling opera-
Equipment selection is governed by circulation tions. The surface volume should be large enough
rates in the wellbore, as well as the concentration to allow enough properly conditioned drilling fluid
and size of drilled solids generated in the well- above suction and equalization lines. This will al-
bore. Large particles are more easily removed than low maintenance of drilling fluid properties and
small particles and should be removed as soon as keep the wellbore full during a wet trip. The sur-
possible to prevent degradation. As particle size face system should consist of three clearly identi-
decreases, separation becomes increasingly more fiable sections (Figure 7-1):
difficult and expensive. Efficient drilled solids man- • Suction and testing section
agement begins with adequate hole-cleaning of
• Additions section
the wellbore. Drilled solids should be brought to • Removal section
the surface with as little degradation as possible.
Most drilling rigs are equipped with many ele-
ments of good solids control such as shale shak- SUCTION AND TESTING SECTION
ers, degassers, desanders, desilters, agitators, and
sometimes mud guns, mud cleaners, and centri- The suction and testing section is the last part
fuges. Surface tank arrangements, including piping of the surface system. Most of the usable surface

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