I. Overview
Polyanionic cellulose (Poly anionic Cellulose) abbreviated PAC, is made from natural cellulose prepared by chemical modification of the water-soluble cellulose ether derivative, is an important water-soluble cellulose ether, as a white or slightly yellow powder, non-toxic, tasteless, it can be dissolved in water, good thermal stability and salt tolerance, antimicrobial resistance. The product is formulated with a good drop of mud fluid loss, inhibition of high temperature resistance. Widely used in oil drilling, especially salt water wells and offshore oil drilling.
2, PAC features
Are ionic cellulose ether with high purity, high degree of substitution, the substituents distribution and other characteristics. Can be used as thickeners, rheology modifiers, fluid loss and the like.
· Suitable for any mud from fresh water to salt water saturation.
Low viscosity type PAC can effectively reduce the filtration rate, without significant increase in system mucus, especially high solid content system.
· Viscous mud type PAC high volume, fluid loss effect is obvious. Especially for low solid mud and solid-free saline mud.
· PAC mud fluid formulated to inhibit clay and shale dispersion and expansion in high salt medium, so that the wall pollution control.
· Excellent mud drilling and workover fluids, but also efficient fracturing fluid.
3, PAC's application
1, PAC use in drilling fluids.
PAC for inhibitors and fluid loss is ideal, PAC mud fluid formulated to inhibit clay and shale dispersion and expansion in high salt medium, so that the wall pollution control.
2, PAC workover fluid applications.
PAC workover fluid formulated with low solid phase warrant blocked due to solid ability to penetrate the layers of production, without compromising production layer; and has a low water loss, so reducing the amount of water entering the production layer, and into the water obstruction due to emulsion formation Township phenomenon.
PAC prepared using workover fluids provides advantages other workover fluid does not have.
Protective layer against the production of permanent damage;
Clean with a carrying capacity of the borehole and borehole maintenance workload reduction;
Has the ability to resist water and sediment infiltration and rarely blistering;
Energy storage or switch between the wells and the wells, workover fluid mud lower than the average cost.
3, PAC used in the fracturing fluid.
Ability 2% KCI solution (must be added the preparation of fracturing fluid) prepared by PAC fracturing fluid and good solubility, easy to use, can be field preparation, and fast gelation speed, carrying sand ability. The use of low osmolarity formations, its fracturing effect is more remarkable.