The typical WBM is made up of the following:
- 76% seawater (offshore)
- 15% barite
- 7% bentonite and
- 2% others
NABMs are emulsions of primarily non-aqueous material. The continuous phase is the non- aqueous base fluid and the internal phase water and various chemicals. As with WBMs, other substances are add to NABMs to achieve desired drilling properties. For example, barite is added to achieve desired density; and proper viscosity is achieved by altering the base fluid to water ratio and using clay materials and emulsifiers to stabilize the water in oil emulsions. The base fluid also serves as a lubricating agent. The composition of a typical NABM
- 46% non-aqueous base fluid
- 33% barite
- 18% brine
- 2% emulsifiers and
- 1% others
Also, three groupings are defined based on aromatic hydrocarbon concentrations, especially:
- Group I (high aromatic content) – such as diesel oil based and conventional mineral oil based fluids.
- Group II (medium aromatic content) – such as low toxicity mineral based fluids; and
- Group III (low to negligible aromatic content) – such as synthetic hydrocarbons and highly processed mineral oils.
On the drilling platform, the mixture of drilling fluid and cuttings are collected for treatment to control solids and recycle the drilling fluid back down the hole. The use of drilling fluids and the associated treatment and fluid circulating systems are critical components in the overall drilling operations.
Drill cuttings treatment options:
1). Non-aqueous drilling mud drill cuttings (oil based mud drill cuttings) minimization treatment. See WPEnvironmental Oil Based Mud Drill Cuttings Management Unit for more details.
2). Water based mud drill cuttings harmless treatment. See WPEnvironmental Water Based Mud Drill Cuttings Management Unit for more details.
3). Non-aqueous drilling mud drill cuttings (oil based mud drill cuttings) harmless treatment. See WPEnvironmental Thermal Chemical Cleaner and WPEnvironmental Thermal Desorption Unit for more details.