What is PHPA mud?

[Drilling Fluids] A class of water muds that use partially hydrolyzed polyacrylamide (PHPA) as a functional additive, either to control wellbore shales or to extend bentonite clay in a low-solids mud. As a shale -control mud, PHPA is believed to seal microfractures and coat shale surfaces with a film that retards dispersion and disintegration.

Can PHPA mud be added to cement?

The remaining polymer can be added to the system as soon as circulation commences. Do not drill cement with PHPA muds, unless the system will be replaced after drilling out, because PHPA muds are sensitive to high pH, especially in the presence of high calcium levels.

Is PHPA a shale control mud?

As a shale -control mud, PHPA is believed to seal microfractures and coat shale surfaces with a film that retards dispersion and disintegration. KCl is used as a shale inhibitor in most PHPA mud designs.

What does PHPA stand for?

1. n. [Drilling Fluids] A class of water muds that use partially hydrolyzed polyacrylamide (PHPA) as a functional additive, either to control wellbore shales or to extend bentonite clay in a low-solids mud.

What is a PHP mud system?

These concepts have a very important consequence. A PHP A mud system must contain enough PHPA to maintain inhibition by encapsulation and to keep surfaces coated with an adsorbed polymer. The PHPA concentration, however, cannot be so high that the viscosity of the water phase becomes excessive.

Can PHPA be added to salt mud?

We experienced one case in which PHPA added to a salt mud produced high permanent viscosity. In this case, the system had a mud weight of 15.6lbm/gal [1870 kg/m3], a chloride concentration of 125,000 mg/L, and a high concentration of filtration control additives.