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DRILLING
METHODS
Reverse mud is a cost effective method for
drilling bore holes of 24” and greater. This
method is most successful in unconsolidated
formations.
Advantages of Reverse Circulation Mud Rotary
1. The near-well area of the borehole is
relatively undisturbed and uncontaminated
with drilling additives and the porosity and
permeability of the formation remains close
to its original hydrogeologic condition.
2. Large-diameter holes can be drilled quickly
and economically
3. No casing is required during the drilling
operation.
4. Well screens can be set easily as part of the
casing installation.
5. Most geologic formations can be drilled,
with the exception of igneous and
metamorphic rocks.
6. Little opportunity exists for washouts in the
borehole because of the low velocity of the
drilling fluid.
Disadvantages include the following:
1. Large water supply is generally needed.
2. Reverse-rotary rigs and components are
large and expensive.
3. Large mud pits are required.
4. Some drill sites are inaccessible because of
the rig size.
5. For efficient operation, more personnel are
generally required than for other drilling
methods.
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