Flow assurance encompasses methods to ensure the full flow capacity of the well bore and flow lines is open for hydrocarbon production, from the reservoir to the refinery. Any blockages in lines at any point in the system causes a bottleneck, and reduces the efficiency of the production operation. These are primarily caused by precipitates, different components of crude which drop out under different conditions. Common flow assurance issues are:
- Asphaltene: precipitating as a result of reduced pressure, and the crude is destabilized
- Paraffin and Wax: precipitates at cooler temperatures, and therefore is more likely found close to the surface, and in subsea flowlines
- Bacterial Colony Growth
Remediation operations are used to remove these unwanted deposits from the tubing, casing or gravel-pack screen, where their presence has a detrimental effect on production. These treatments normally use acid or solvent systems that are placed in the effected area to soak. Key parameters in treatment design are the placement technique, correct chemical selection and soak time. Chemicals should be selected based on their effectiveness at dissolving the suspected damage and therefore laboratory tests at relevant temperatures and, if possible, pressures, are desirable to determine the most effective solution. Samples of crude, the deposits themselves, produced water and treatment water are vital. However, the best way to ensure flow assurance is prevention, for which a range of chemicals may be continuously of intermittently injected or placed in flow lines, to reduce and in some cases, eliminate deposition.