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.

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.

Can you drill cement with PHPA mud?

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. If drilling cement with a PHPA system is unavoidable, pretreat the system with 0.251bmlbbl [0.7 kg/m3] sodium bicarbonate.

Is PHPA a water soluble polymer?

PHPA is a co-polymer of anionic character and high molecular weight. It is a water-soluble polymer, which is primarily used as a highly efficient fluid loss reducer, Viscosifier and protective colloid for shale’s and cutting in fresh water, calcium, sodium brines and KCL mud systems.

Can KCl be used as a shale inhibitor in PHPA mud?

KCl is used as a shale inhibitor in most PHPA mud designs. In low-solids muds, PHPA interacts with minimal concentrations of bentonite to link particles together and improve rheology without increased colloidal solids loading.

Which drilling fluid is compatible with PHPA?

It is compatible with most of the drilling fluid products, biopolymers, PAC, CMC. It maintains borehole stability by preventing shale swelling and erosion. PHPA maintains viscosity in solid free drilling fluid. As a Bentonite extender in low solids non-dispersed mud, it can be used along with small addition of Bentonite to suspend weight material.