Rheological Additives for Oil Based Muds

Organoclays for drilling fluid systems

Which organoclay do you recommend for our drilling fluid system?

a. It will be system dependent, but we have developed a chart.
b. The first two considerations are base fluid and temperature requirements.

Incorporation of organoclays

What is the best way to incorporated organoclays?

a. In a fresh mud, we suggest adding the organoclay before other ingredients to maximize its dispersion.
b. While drilling, they can be added at any time. Downhole temperature and sheering through the drill bit will yield the clays.
c. In general, high performing organoclays will yield in one circulation, whereas economy grades may require 2-3 passes through the bit.

Performance Indicators

Is a simple organoclay-base fluid test an indicator of performance?

No! There are too many factors. Simply thickening a base fluid, like diesel, does not imply good drilling fluid performance.

Yield point

How much organoclay do I need to add for a yield point

a.  It depends on a number of factors including: base fluid, oil to water ratio, mud weight, sheer history, surfactant package, rheology modifiers, other solids, etc.
b. A loading scan in a complete mud system is the best way to determine the amount of organoclay needed for a specific yield point range. This takes into account the base oil, OWR, surfactant package, and total solids in a given system. 

Improvement of suspension

How can we improve suspension without impacting viscosity?

a. BYK has two choices. For moderate temperature systems, BYK-GO 8720 will dramatically increase the low shear rate viscosity. It is most effective in systems containing organoclays and oil wet drill solids.  For deeper and hotter wells, GARAMITE-7303 has shown synergy with traditional organoclays. In either case, a pilot test beginning with 0.5 – 1.0 lb/bbl has shown marked increases.

Reduction of mud viscosity

We need to reduce the mud's viscosity.

a. The first line of attack should be optimizing the existing solids control equipment to minimize drill solid contamination. This takes time and may also require dilution with base oil.
b. Alternatively, you could treat the mud with 0.1 – 1.0 lb/bbl BYK-GO 8702 to quickly reduce excessive gel strengths and the yield point. This will enable the solids to settle in the settling tank for removal while drilling ahead. This powerful deflocculant should be pilot tested to avoid over-treatment.

Removal of H2S

We hit a pocket of sour gas and need to remove H2S!

a. BYK-GO 8780, liquid zinc, will rapidly treat and precipitate out H2S gas.  It is recommended to maintain excess scavenger in the system to prevent any H2S gas to reach the surface. If there is a remote chance of encountering sour gas in a field, please maintain a suitable scavenger at the well site.