DX
PHPA drilling fluid additive is designed to be
extremely effective in stabilizing sloughing shales,
providing viscosity and filtration control, and
producing reduced torque and drag in fresh water
and KCl drilling fluids. High viscosity is achieved
with low polymer concentrations.
Typical
Appearance
White
free flowing powder
Properties
Charge
30%
Anionic
Molecular
Weight
>15
Million
pH,
0.5% solution
7.0
Advantages
Enhances
drilling fluid viscosity. Protects water sensitive
sloughing shales. Minimizes problems near the well
bore. Reduces torque and drag. Reduces or eliminates
bit balling.
Solids
Control
As with any
fluid, drilled solids content should be kept to a minimum.
Initial breakover to the system with DX PHPA may blind
the shaker screens due to initial high viscosities. Once
the polymer fluid is sheared, screen blinding problems
are minimal. Usually 1-2 circulations are required.
Rheology
To achieve good hole
cleaning and fluid shear-thinning properties, maintain a PV:YP ratio
of 1:1 to 1:2. If additional viscosity is desired, use 0.75 lb/bbl
of polymer. Also 4-6 lb/bbl of pre-hydrated bentonite can be added
to supplement to viscosity but the viscosity will build as drilled
solids are incorporated into the system. Attention is focused on
effective solids control, polymer concentrations and proper additions
of KCl.
Thermal
Stability
DX
PHPA polymer is thermally stable to 300°F (150°C) and has
used successfully in wells with bottom hole temperatures in excess
of 350°F (175°C). DX PHPA should be added to the system very
slowly, with a funnel, at a rate of 30-45 minutes per bag.
Treatment
of
Contaminants
Maintain calcium ion
concentration (Ca+2) below 400 ppm with soda ash, but leave 100
ppm Ca+2 in the system to prevent CO2 ion-blocking polymer absorption
on the shale. Use lime with discretion to maintain Ca+2 in system.
Dump excessive green
cement into the reserve pit.
Never add phosphates
to the system as this will have an effect similar to that of a
strong thinner such as chrome lignosulfonate.
Do not use chrome
or zinc compounds in the system.
Control hydrogen sulfide
(H2S) by increasing mud weight and adding zinc carbonate.
DX Oilfield Products, LLC, 300 Jackson Hill St., Houston, Texas 77007