offshore drilling station

Drilling Fluid

Drilling Fluid

Stabilizing water-sensitive shales and the aggregation of cuttings

Onshore and offshore oil and gas producers rely heavily on custom-formulated clear brine solutions containing various mineral salts for different types of drilling and completion activities. These solutions are used in oilfield completion and workover operations to reduce water inflow and create osmotic forces to prevent absorption of water by shales.

Potassium muds are the most widely accepted water mud system for drilling water-sensitive shales, especially hard, brittle shales. K+ (Potassium) ions attach to clay surfaces and lend stability to the shale exposed to drilling fluids by the action of bit. The ions also help hold the cuttings together, minimizing dispersion into finer particles.

drill blueprint

Calcium Chloride and Magnesium Chloride are used in drilling mud to cool and lubricate the bit and to remove cuttings from the hole. This helps add density to the mud to overcome formation pressures and keep the oil, gas, and water in place. The divalent calcium and magnesium ions inhibit clay swelling, dispersion and migration.

During oil based drilling in mud, Calcium Chloride functions as swelling-agent.