As the industry increasingly develops extended-reach, high-angle and deepwater wells, one of the considerations is fluid lubricity when designing a completion or workover fluid. Fluid lubricity plays an important role in choosing the optimum fluid for the operation.
This paper presents lubricity or coefficient of friction data for various completion and workover brines. Two commercial brine lubricants were also evaluated to determine their effectiveness in increasing brine lubricity. Results indicate that lubricity of brines varied with the type and concentration of salt, but generally increased with increasing salt concentration. For example, sodium and potassium brines behave differently as compared to calcium brines with regard to lubricity. Also, zinc bromide containing brines show very high lubricity, suggesting that using a lubricant is generally unnecessary. Furthermore, practical guidelines are provided to better design brine completion and workover fluids for well operations where reducing torque and drag is required. Case histories are also presented which successfully applied one of the lubricants in the fields.