The filtration loss of polyanionic cellulose plays an important role in oil drilling, which is mainly reflected in the following aspects:
1. Stabilizing the wellbore
Drilling fluid filtration is inevitable during drilling. If the filtration loss is too large, it is easy to cause shale expansion and collapse, resulting in instability of the wellbore. Polyanionic cellulose can reduce the filtration loss of drilling fluid, which helps to form a thin and dense filter cake, thereby better protecting the wellbore and reducing accidents such as wellbore collapse.
2. Reduce torque
When the filtration loss increases, the filter cake will thicken, the wellbore diameter will be reduced, and a large torque will be caused to the rotating drill bit, increasing the difficulty and energy consumption of drilling. Polyanionic cellulose controls the filtration loss, which can make the filter cake thickness moderate, reduce the torque of the drill bit, and improve drilling efficiency.
3. Prevent differential pressure from sticking the drill
If the filtration loss is too large, the filter cake will thicken, which will easily cause pumping and pressure fluctuations when drilling, resulting in differential pressure from sticking the drill bit. Polyanionic cellulose reduces the filtration loss, making the filter cake denser and more uniform, reducing pressure fluctuations and the risk of differential pressure sticking.
4. Protecting the oil and gas layer
The appropriate filtration loss can make the filter cake formed by the drilling fluid on the well wall have a lower permeability, prevent the solid particles and filtrate in the drilling fluid from excessively invading the oil and gas layer, avoid damage to the oil and gas layer, and help improve the efficiency and output of oil and gas production.
