Rheological Additives for Oil Based Muds
a. It will be system dependent, but we have developed a chart.
b. The first two considerations are base fluid and temperature requirements.
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.
No! There are too many factors. Simply thickening a base fluid, like diesel, does not imply good drilling fluid performance.
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.
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.
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.
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.