Page 107 - Shale Shakers Drilling Fluid Systems

90 SHALE SHAKERS AND DRILLING FLUID SYSTEMS

drilling fluid if no weighting agents are added. ated individually with careful consideration of the
These savings are easily documented. Less appar- risk of the problems associated with drilled solids.
ent, however, will be the additional expenses in-
curred because of excessive drilled solids in the
drilling fluid. These problems will obviously in- WASTE MANAGEMENT
crease the well cost as described previously.
Another common mistake, usually made while Failure to remove drilled solids with solids con-
drilling with weighted drilling fluid, is to relate the trol equipment results in solids control with dilu-
cost of the discarded weighting agent with the tion. This creates excessive quantities of fluid that
drilled solids discard. The cost of discarded weight- must be handled as a waste product. It can be
ing agents (barite or hematite) can be relatively very expensive if this excess fluid must be re-
small compared to the problems associated with moved from the drilling location. Even if the fluid
drilled solids. This is particularly true in the expen- can be handled on-site, large quantities of fluid
sive offshore environment. Even in less expensive frequently increase costs.
land drilling, a comparison normally justifies dis- Smaller quantities of waste products can signifi-
carding weighting agents to eliminate drilled solids. cantly decrease the cost of a well. Decreasing the
Solids control equipment properly used, with quantity of drilling fluid discarded with the drilled
the correct drilling fluid selection, will usually solids will decrease the cost of rig-site cleanup.
result in lower drilling costs. Decisions made for Dilution techniques for controlling drilled solids
specific wells depend on the well depth and drilling concentrations greatly increase the quantity of
fluid density. Shallow, large-diameter, low mud- waste products generated at a rig. This results in
weight wells can tolerate more drilled solids that an additional expense that ultimately adds to the
more complicated wells. Each well must be evalu- total cost of drilling.