PAC HV

Overview of PAC-HV

High-viscosity polyanionic cellulose (PAC-HV) is a polymer compound widely used in fields such as oilfield drilling, water treatment, and construction materials; its performance directly impacts the efficiency and safety of industrial applications. Given its unique thickening, suspending, and stabilizing properties, quality control for PAC-HV is of particular importance. To ensure compliance with production requirements and industry standards, systematic testing of its physicochemical properties, viscosity characteristics, and purity is essential.

Applications in Oil and Gas Drilling and Well Construction

Drilling fluid and completion fluid technologies are vital components of oil drilling engineering, playing a crucial role in ensuring safe, high-quality, and rapid drilling operations. As a class of additives used to modify the properties of drilling and completion fluids, cellulose derivatives primarily function to reduce fluid loss and increase viscosity.

The fluid-loss control mechanism of oil-drilling grade CMC is generally understood to involve the following: enhancing the system's coalescence stability by forming an adsorbed solvation layer on the surface of clay particles; inhibiting the aggregation and enlargement of fine clay particles through a protective effect; and reducing mud cake permeability by increasing filtrate viscosity and plugging pore spaces.
 

Petroleum-grade CMC disperses easily in all water-based drilling fluids, making it suitable for systems ranging from fresh water to saturated brine. In low-solids and solids-free drilling fluids, it significantly reduces fluid loss and mud cake thickness while strongly inhibiting shale hydration.

Compared to CMC produced via conventional processes, petroleum-grade PAC exhibits the following characteristics:

a. High degree of substitution, uniform substitution, high transparency, controllable viscosity and reduced water loss;
b. Suitable for any water-based mud, whether freshwater, seawater, or saturated brine;
c. Mud formulated with this product exhibits excellent water loss reduction, controllability, and high-temperature resistance;
d. Mud formulated with this product possesses rheological properties;
e. Inhibits the dispersion and expansion of clay and shale in high-salt media, thereby controlling wellbore fouling;
f. Stabilizes soft soil structures, preventing wellbore collapse due to rising water levels;
g. Reduces the accumulation of drill solids in the mud as the drill passes through rock surfaces;
h. Suppresses turbulence in the drill string, minimizing pressure loss in the return system;
i. Enables increased mud production and reduced filtrate loss;
p. Stabilizes mud foam.
 

Therefore, polyyanionic cellulose (PAC) is ideal as an inhibitor and fluid loss reducer. PAC-based drilling mud inhibits the dispersion and expansion of clay and shale in high-salt media, controlling wellbore contamination.

Furthermore, PAC-based workover fluids are low in solids, preventing solids from hindering the permeability of the production zone and thus avoiding damage to it. They also exhibit low filtrate loss, indicating strong resistance to fluid loss and minimal water ingress into the production zone. This prevents water from entering due to emulsion blockage and causing waterlogging. This prevents permanent damage to the production zone and provides the ability to clean the wellbore.