Drilling with foam and polymers
Drilling with foam and polymers has been adVantages and may improve drilling in certain ground conditions. Some beneﬁts include:
- Ability to clean the hole with low annular velocity using a quality foam with the correct mixture may allow for sufﬁcient hole cleaning with the annular velocity as low as 150 feet (46 m) per minute
- Utilizing a strong faom/polymer mixture, low stability formations can be drilled with minimal borehole erosion. This mixture reduces the need for high annular velocity and will cuttings during rod changes. The polymer foam will form a ﬁlter cake on borehole wall, reduce hole collapse and inhibit swelling of clays.
- Foam injection also aids in drilling in borehole where water intrusion creates high back pressures. The foam mixture will reduce the head pressure lowering the peak unloading pressure and operating pressure.
LIGHT MIXTURES CREATES LARGE BUBBLES LIKE A BUBBLE BATH
HEAVY MIXTURE CREATES SMALL BUBBLES LlKE SHAVING CREAM
A heavy foam mixture will create the best cutting carrying capacities and low quality foams will have tendency to break down quickly in the hole allowing cutting to fall out of the solution.
Note: When ﬁnished drilling with foam, it is necessary to rinse all drilling tools with fresh clean water and lubricate them properly. Prolonged exposure to the atmosphere creates a corrosive reaction between the steel and the foam. Corrosion stress risers are a common cause of drilling tools failures.