Polyanionic Cellulose in Petroleum Drilling Fluid

Polyanionic Cellulose in Petroleum Drilling Fluid

Introduction to polyanionic cellulose (PAC)


Polyanionic cellulose, abbreviated as PAC, is a water-soluble derivative of cellulose ether, which is obtained by chemically modifying natural cellulose fibers. It is an important water-soluble cellulose ether and is usually used in its sodium salt form. It is widely used in petroleum drilling, especially in brine wells and offshore oil drilling. PAC has good heat stability, salt resistance, and strong antibacterial properties. Due to its excellent thickening, stability, suspension, and high-temperature resistance properties, PAC is widely used in drilling fluids. Its usage is extensive and can be applied to all industries that can use carboxymethyl cellulose, providing more stable application performance. PAC is also more suitable for offshore drilling. What role does PAC play in drilling fluids?


The Role of polyanionic cellulose (PAC) in Drilling Fluids


  • Drilling mud is a suspension of solids in an aqueous solution, like other colloidal suspensions; it has a certain service life. Oil drilling grade PAC can help stabilize it, thereby extending its service life. The effect is particularly noticeable in suspensions containing dissolved salts.


  • Drilling mud containing polyanionic cellulose (PAC) can form thin and sturdy wellbore walls and low-permeability filter cakes, thereby reducing the phenomenon of hole shrinkage and collapse caused by mud loss.


  • Mud that contains added PAC is rarely affected by molds, so it does not need to maintain a high pH or use a preservative. It can remain stable even with a certain range of temperature changes during drilling, as the amount of other chemical agents used in it is correspondingly reduced.


  • Drilling mud with PAC has a lower initial gel strength, making it easier to remove air and debris from the mud pit. PAC-HV is suitable for low-density and small-quantity mud and can increase viscosity and reduce filtration. A small amount of PAC can replace a large amount of clay. This type of mud can reduce the difficulties encountered during drilling CaSO42H20 or CaSO4 salt. However, PAC-LV is suitable for high-density mud, can reduce filtration but has little effect on viscosity. When using it, dissolve PAC in water to create a solution (generally 1/40-1/20), and then add it to the mud. PAC can also be compounded with other chemical agents and added to the mud.


As a leading PAC and CMC supplier, our PAC-HV/LV (oil drilling grade) and CMC-HV/LV are advantageous because of their small dosage, high yield,  anti-bacterial, good salt tolerance properties and convenient to use, reduction of fluid loss, and improvement of viscosity, flowing control and strong suspending capability, environmentally friendly, non-toxic, harmless and odorless, and good liquidity, convenient to construction.