Carboxymethyl starch is an anionic starch ether, an electrolyte that dissolves in cold water. Carboxymethyl starch ether was first made in 1924 and was industrialized in 1940. It is a kind of modified starch, belongs to ether starch, is a kind of water-soluble anion polymer compound. It is tasteless, non-toxic, not easy to mould when the degree of substitution is greater than 0.2 more easily soluble in water.

It used as mud stabilizer, a water-retaining agent with the functions of reducing fluids(water) loss and improving the coagulation stability of clay particles in the oil drilling mud. And it is better to carry the drilling cuttings. Especially suitable for high-salinity and high-PH Salinization well.

CMS has a variety of properties such as thickening, suspension, dispersion, emulsification, bonding, water retention and protective colloid.It can be used as an emulsifier, thickening agent, dispersant, stabilizer, sizing agent, film-forming agent, water retention agent, etc. It is widely used in petroleum, textile, daily chemical, cigarette, paper making, construction, food, medicine and other industrial sectors, known as “industrial monosodium glutamate”.

Carboxymethyl starch sodium (CMS) is a kind of modified starch with carboxymethyl etherification, the performance is better than carboxymethyl cellulose (CMC), as the best product to replace CMC.The aqueous solution of CMS is stable and has excellent performance, which has the functions of bonding, thickening, water retention, emulsification, suspension and dispersion.CMS plays an important role in reducing water loss and improving the coalescence stability of clay particles in drilling fluid as a mud stabilizer and water-retaining agent.CMS has little effect on the plastic viscosity of mud but has a great effect on the dynamic force and shear force, which is conducive to carrying drilling cuttings, especially when drilling salt paste, which can make the drilling fluid stable, reduce the amount of loss, and prevent the wall collapse.It is especially suitable for saline Wells with high salinity and high PH value.