BAKER HUGHES - Drilling Fluids Reference Manual

RESERVOIR APPLICATION FLUIDS
The term brines refers to solutions prepared from dissolved salts in water or naturally occurring
seawater or formation waters. Brines are considered non-formation damaging because they can
deliver the appropriate density desired and can be filtered to remove particulates which would
cause potential damage. The selection of appropriate brine based on the above criteria will deliver a
system which minimizes hydration and dispersion of formation clays and is compatible with most
additives used during completion and workover. The additives typically used in completion and
workover are surfactants, viscosifying agents, bactericides, corrosion inhibitors, etc.
Clear brines are used for a wide variety of completion and workover applications.
• Packer fluids
• Kill fluids
• Under-reaming fluids
• Drill-in fluids
• Drilling fluids
• Perforating fluids
• Gravel packing fluids
Factors of most importance when selecting a brine for a particular application is density, formation
damage, crystallization, and, of course, economics. Many different types of salt can be used. Some
can be used as an individual salt to achieve the desired properties or can be utilized as mixed salt
type brine systems. Costs, density, and formulations can be drastically different based on the brine
type and crystallization point desired. Generally, the higher the density and lower crystallization
point desired, the higher the cost. Consequently, it is imperative to formulate the proper brine
density and its desired properties at optimum cost.
Effects of Temperature and Pressure
Temperature
• Volume expansion
• Density decrease
• Crystallization
Pressure
• Compressibility
• Well control
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 6-42