Potassium chloride (KCl) is a soluble salt that is an extremely efficient shale stabiliser when drilling hydro sensitive clays and shales. Inhibition is provided through ion exchange; the potassium ion enters between the individual clay platelets in the shale so that they are held together, thus eliminating entry of water from the drilling fluid. Potassium chloride (KCl) powder is a high purity, dry crystalline inorganic salt used to form clear brine used in workover and completion operations which require densities raning from 8.4 to 9.7 lb/gal (1007 to 1162 kg/m3).
Turkey Potassium chloride (KCl) can be added directly to a drilling fluid system to enhance its inhibitive quality, which helps to stabilise water sensitive clay and shales. It can also be used as a weighting agent ranging in densities from 1.005sg (8.4lb / gal) to 1.162sg (9.7lb / gal). POTASSIUM CHLORIDE (KCl) solution becomes saturated near 1.162sg (9.7lb / gal); the closer to saturation the less soluble the salt becomes. Potassium Chloride (KCL) is used for shale inhibition in KCL drilling fluid systems and as a brine in Mixed Salt Systems. The ionic diameter of potassium is 2.66 A, very close to the available distance of 2.8 A in the lattice space of the clay structure. A cation slightly smaller than 2.8 A is desirable to allow for crystalline compaction.
Potassium chloride is used in drilling fluids to aid in the stabilization of shales and to control swelling clays. The accurate determination of the potassium ion content is necessary to control the inhibition characteristics of the drilling fluid. This procedure is used to measure the potassium ion content in mud filtrates at levels above 5000 milligrams per liter or 3.5 pounds per barrel KCl. The procedure is most accurate in the range between 10,000 mg/L (2%) and 40,000 mg/L (8%) KCl and is suspect below 10,000 mg/L (2%) KCl. Potassium is precipitated in a centrifuge tube as the perchlorate salt, and then the precipitate volume is measured. The potassium ion content is then read from a prepared standard curve.
Potassium Chloride is a particularly economical and efficient inhibitor when used as a drilling fluid for critical water-sensitive shale formations. Potassium chloride (KCl) powder is a high purity, dry crystalline inorganic salt used to form clear brine used in workover and completion operations which require densities raning from 8.4 to 9.7 lb/gal (1007 to 1162 kg/m3).Potassium Chloride provides clay and shale inhibition through the Potassium ions, which compete with any exchangeable ions present in clays and shales to bind the clay platelets together, effectively minimizing swelling and dispersion. Potassium interactions with clay surfaces can be traced to two effects: ionic size and hydrational energy. Potassium ions are of the proper size to fit snugly into the spaces between the two silica tetra-hedral layers which contact each other in the formation of a three-layer clay packet.
Potassium-based muds are used in areas where inhibition is required to limit chemical alteration of shales. Potassium chloride performance is based on cationic exchange of potassium for sodium or calcium ions on smectites and interlayered clays. The potassium ion compared to calcium ion or other inhibi-tive ions, fits more closely into the clay lattice structure, thereby greatly reducing hydration of clays. Potassium-based muds perform best on shales containing large quantities of smectite or interlayered clays in the total clay fraction. Shallow shales, containing large amounts of montmorillonite, however, still swell in a potassium-based system. The benefits may not justify the cost of using a potassium-based mud in this type of environment.