Hydroxyethyl Cellulose * Cementing

1. Control cement slurry filtration loss

During the cementing process, cement slurry filtration control is very critical. When cement slurry is pumped into the annular space between the wellbore and the casing, the liquid part of the cement slurry may penetrate into the formation due to the pressure difference. Hydroxyethyl cellulose (HEC) can form a spatial network structure in the cement slurry system, which can prevent excessive filtration of liquid.

For example, in formations with high permeability, cement slurry without HEC may cause the cement slurry to lose water and become thicker due to excessive filtration, making it difficult to distribute evenly in the annular space. After adding HEC, it can form a thin and dense filter cake on the surface of the well wall, reduce the filtration rate of cement slurry, ensure that enough cement slurry remains in the annular space, and form a good quality cement ring.

2. Improve the rheological properties of cement slurry

HEC can adjust the rheological properties of cement slurry, so that the cement slurry has good fluidity and pumpability. It can increase the viscosity of cement slurry and give cement slurry shear thinning properties to a certain extent.

In actual cementing operations, cement slurry needs to pass through complex downhole pipes and tools to reach the destination. When cement slurry with shear thinning characteristics passes through a high shear area (such as through a narrow oil pipe, drill pipe, etc.), its viscosity will decrease, making it easier to pump; when leaving the high shear area, the viscosity will recover, which is conducive to the uniform distribution of cement slurry in the annular space and ensures the uniform quality of the cement ring.

3. Improve displacement efficiency

During the cementing process, the drilling fluid in the casing needs to be displaced so that the cement slurry occupies the annular space between the casing and the well wall. HEC can optimize the rheological properties of cement slurry, thereby improving displacement efficiency.

Because HEC improves the rheological properties of cement slurry, cement slurry can better achieve laminar displacement when displacing drilling fluid. Under laminar flow, cement slurry can push drilling fluid out of the annular space in a relatively stable and smooth manner, reduce the mixing between drilling fluid and cement slurry, ensure that cement slurry can completely fill the annular space, and improve the bonding quality of the cement ring.

4. Enhance the strength and toughness of cement stone.

HEC can improve the strength and toughness of cement stone to a certain extent. During the cement hydration process, HEC can interact with cement particles and fill the gaps between cement particles.

When the cement stone is subjected to formation pressure or other external forces, this filling effect can enhance the deformation resistance of the cement stone and prevent the cement stone from cracking or breaking.