BAKER HUGHES - Drilling Fluids Reference Manual

Baker Hughes Drilling Fluids
Filter Cake
Once part of the clouding polyol in solution becomes hydrophobic, a significant improvement in
filter cake quality is seen. Water tends to bead on the surface and the cake is easier to “peel off”
the filter medium.
Well Clean-Up
Production after acidization and completion of wells has been above operator expectations.
Unfortunately, no information on skin damage and comparisons of production rates before and
after using polyols has been made available. It is thought that quick plugging of low permeability
sandstones (< 20 mDarcy) by the polyol leads to minimal formation damage inside the reservoir.
Later acidization could then reach beyond the invasion zone around the wellbore leading to a
better clean-up and enhanced production.
Viscosity Effect
In general, polyols added at low concentrations (< 5%) have little effect on the viscosity of the
drilling fluid. At increased concentrations, there will be some variation in viscosity with the
maximum rheology obtained in the 110° to 130°F temperature range.
Effect of Temperature on Yield Point at 10% AQUA-COL TM
Figure 3-20
Effect of Temperature on Yield Point at 10% AQUA-COL TM
Environment
As a group, low molecular weight polyols are considered low in toxicity and readily
biodegradable. The fact that they are water soluble means that they are able to disperse in the
water column and biodegrade easily. An added feature of polyol use in water-base fluid is the
reduction in dilution rates due to their inhibitive nature which reduces the overall volume of
water-base fluid products discharged to the environment.
Baker Hughes Drilling Fluids
Reference Manual
Revised 2006 3-77