Scale Inhibition
and Removal
Details
Oilfield reservoirs contain brines in equilibrium
at reservoir pressures and temperatures. As the
reservoir is produced, the delicate balance is changed.
Temperatures often drop and pressure and gases are
released, often affecting pH and stability of the brines.
Brines may have been saturated at initial conditions,
but become supersaturated under the dynamics of
production. When this occurs, the crystallization
process begins, eventually forming mineral scale
deposition at nucleation sites throughout the
production system.
When scale adheres, problems occur including:
• Producing channels in the reservoir
become plugged
• Well perforations are blocked
• Pumps load with the scale and fail
• Tubing becomes plugged with scale, reducing fluid flow
• Valves become coated with scale and fail
to function
• Equipment and heat exchangers become scale coated, lose efficiency and eventually fail
• Salt water injection and disposal wells plug off with mineral scale, forcing pumps to work harder, requiring equipment replacement and injection well and reservoir remediation
• Well perforations are blocked
• Pumps load with the scale and fail
• Tubing becomes plugged with scale, reducing fluid flow
• Valves become coated with scale and fail
to function
• Equipment and heat exchangers become scale coated, lose efficiency and eventually fail
• Salt water injection and disposal wells plug off with mineral scale, forcing pumps to work harder, requiring equipment replacement and injection well and reservoir remediation
There is no uniformity to oilfield brines, nor is there
uniformity to the mineral scales that form. For
deposits that have already formed, an inhibitor will
have little or no impact on removing the deposit. It is
necessary to select the proper removal chemistry or
mechanical solution for the deposit. Many times, scale
deposits are comprised of multiple scale types. In
addition, oftentimes scale co-precipitates with paraffin
and asphaltene, which complicates the removal
process. The best solution requires an analysis of
the deposit at a Water Technologies & Solutions’
laboratory to determine the composition. With this
information, a local Water Technologies & Solutions’
technical team can prescribe a cost effective removal
program to reduce solid waste and get your system
running at enhanced efficiency.
