Polymer drilling fluid provides nondamaging inhibition

A new polymer drilling fluid combines the advantages of popular nondamaging workover fluids with the more stringent performance requirements of drilling muds. Polymer fluid evolution. In the early 1960s, nondamaging polymer-carbonate workover and completion fluids were introduced. The workover industry immediately accepted the nondamaging aspects and overall utility of these fluids. Based on this success, the drilling industry attempted to use these workover products for drilling fluids. Unfortunately, as drilling fluids, workover polymer fluids created more problems than they solved. The fluids were not solids tolerant. Foaming or air entrainment occurred. Too much water and polymer were used, so costs were exorbitant. Incorrect polymers or combinations of polymers were used, and sometimes polymers accidently cross-linked. As a consequence, the drilling industry shunned these systems. Drilling requirements demand a polymer satisfying the following: Easy to mix and maintain Cost effective Tolerates solids buildup Stabilizes shales Effective in all makeup waters Unaffected by contaminants or salts Essentially nondamaging Predictable performance under varying conditions Optimally, one product satisfying these eight requirements was needed to formulate a true polymer drilling fluid.