Water-based muds require viscosifiers compatible with the base fluid and tolerant to drilling conditions. AES Drilling Fluids has a range of options from basic gel additives to enhanced grades of xanthan gum, such as ENERZAN.
ENERZAN L liquid xanthan gum
There are several kinds of viscosifiers used in water-based muds in order to provide quality hole cleaning and solid-suspension characteristics. Viscosifiers work in concert with all of the mud components, meaning there is a wide range of options for the numerous water-based drilling fluids available.
Bentonite, a name given for commercially mined sodium montmorillonite (a form of smectite clay) is the most common clay additive used in both oil and water based drilling fluids. When a bentonite clay particle is hydrated, the interlayers expand as water is absorbed. This expansion is what creates viscosity in a clay-based drilling fluid system. The distance at which the particle expands is related to the type and amount of cations present
Another type of commercial clay often used is Attapulgite, a needle-shaped non-swelling particle primarily used in saltwater muds. The inherit shape of this material is responsible for the clay’s behavior and ability to build viscosity. Because of its non-swelling and crystalline structure, Attapulgite alone does not provide sufficient filtration control.
Polymers, defined as large molecules comprised of small, identical recurring units, are widely used in water-based muds. Their structures can usually be classified as linear, branched, or cross-linked. However, polymers can also be categorized by their origin: natural, modified, or synthetic.
One of the most often used natural polymers is known as xanthan gum. When hydrated, xanthan gum arranges itself as a long branching structure with weak hydrogen bonding – this provides it’s viscosifying characteristics.
The effectiveness of polymers/starch additives rely on many factors including the concentration of the material and the fluids inherent pH/hardness/salinity. Starch additives, typically added for filtration control, also can provide viscosity as a secondary function.
Common polymers used in water-based drilling fluids:
Our expertise insures our drilling fluid systems are maintained at maximize performance at with cost. Our TechTips series seeks to educate customers with some of this knowledge related to key drilling fluid concepts.
Filtration control additives vary by performance requirements to minimize cost for an application. Contact your AES Drilling Fluids Account Manager to review product details for your application.