How Are Reactive Clay and Fine Solids Controlled in Drilling?
Reactive clay does not cause problems only by swelling. Clay and shale broken during drilling can divide into progressively smaller particles and enter the active mud. As these fines accumulate, mud weight, viscosity, pump pressure and total solids loading can increase.
What are fine solids?
Large, intact cuttings are easier to remove mechanically at surface. When cuttings soften in water and are repeatedly broken down through pumps and lines, they can become very small particles that are difficult to remove from the active mud.
How do fine solids affect the mud?
As particle size decreases, total surface area increases. This can raise viscosity and mud weight, increase pump pressure and change filtration and polymer behaviour.
Why can mud weight rise even when sand content is low?
The sand test mainly shows the coarser fraction. Very fine clay particles may not appear as high sand content. Therefore the combination of low sand + rising mud weight + increasing viscosity can indicate fine-solids accumulation.
What does CLAY BUSTER do?
CLAY BUSTER is a polymeric additive used in compatible water-based drilling fluids to support control of reactive clay and fine-solids loading. It is not the same as the direct clay-swelling inhibition function of MUDOCLAY-OFF or the dispersant function of MUD-OFF.
What is the difference between CLAY BUSTER and MUDOCLAY-OFF?
MUDOCLAY-OFF is aimed at controlling water uptake, swelling and stickiness of reactive clay. CLAY BUSTER is a separate product for management of reactive clay and fine-solids loading in the active mud.
What is the difference between CLAY BUSTER and MUD-OFF?
MUD-OFF is a dispersant for controlling clay/solids dispersion and related rheology. CLAY BUSTER is a reactive-clay and fine-solids control polymer.
Can fine-solids problems be solved by chemicals alone?
No. Adequate circulation, hole cleaning, mechanical solids separation and controlled dilution when required are also part of the program. Chemicals do not replace poor hole cleaning.
Why can mud weight rise without adding barite?
If mud weight rises without barite addition, formation solids may be entering the system. Cuttings, sand and especially very fine clay can contribute to the increase.
What should be monitored in the field?
- Trend in mud weight over time,
- Marsh-funnel time,
- sand content,
- pump pressure,
- appearance of returned cuttings,
- torque and hole-cleaning behaviour.
CLAY BUSTER – Reactive Clay & Fine Solids Control Additive
CLAY BUSTER is a polymeric additive used in compatible water-based drilling fluids to support management of reactive clay and fine-solids loading.
Frequently asked questions
Does more bentonite solve a fine-solids problem?
Usually not. If the system already receives high fine-solids loading from the formation, unnecessary bentonite can increase total solids loading further.
Is dilution alone enough?
It may provide temporary relief, but if new fines continue to enter the system, the root cause must also be controlled.