BAKER HUGHES - Drilling Fluids Reference Manual

TABLE OF CONTENTS
• The ability to form hydrates in SBM is related to the gas type, with higher salinities required
for heavier gases.
Fluids that provide additional gas hydrate suppression and fluids that can be formulated at lower
densities than traditional deep water fluids is the focus of ongoing work at Baker Hughes Drilling
Fluids. These fluids utilize low molecular weight organic compounds for enhanced gas hydrate
inhibition. NF3 (No Freeze, No Frac, No Formation Instability) is the sequel to Baker Hughes
Drilling Fluids’ first product of this type, referred to as NF2 ® (No Freeze, No Frac). NF3 has a
lower specific gravity than NF2® and has the additional function of benefiting borehole stability
as well as providing gas hydrate inhibition. NF3 can be added to standard deep water, water
based drilling fluids at concentrations from 5% to 40% by volume depending on the degree of gas
hydrate and shale inhibition desired. The ability to use NF3 at these various concentrations will
allow flexibility between the required density, amount of shale inhibition, and the amount of gas
hydrate inhibition desired.
NF2 ® , a low molecular weight, environmentally friendly glycol, is ideal for deepwater applications
where high gas hydrate suppression and low fluid density (due to low fracture gradients) is
required. NF2 ® is compatible in both fresh and salt water (up to and including saturated brines)
drilling fluids. NF2 ® is particularly useful in formulating pills for choke and kill lines whenever
favorable conditions exist for the formation of gas hydrates.
These products have been successfully incorporated into inhibitive water based fluid systems in the
Gulf of Mexico and elsewhere. A major operator in the GoM utilized the unique characteristics of
these products in their world record setting water depth well of 7,800 ft. (2377 m.) with great
success. A 9.3 ppg (1.12 sg) fluid was built using salt and 10% NF3 yielding a fluid capable of
suppressing hydrates in 7799 ft. (2377 m.) of water, or in the presence of 7799 ft. (2377 m) of
hydrostatic pressure and a sea floor temperature 36°F (2 0 C).
Figure 13 - 8
Gas Hydrate Equilibrium Chart
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 13-18