Flow assurance
Flow assurance is the discipline of ensuring that oil, gas and water keep flowing without interruption from the reservoir to the point of sale. It covers preventing and removing deposits such as paraffin, asphaltenes, scale and hydrates, and managing emulsions, corrosion and solids.
What is flow assurance?
SLB’s Energy Glossary describes flow assurance as the design, strategies and principles for ensuring uninterrupted hydrocarbon production from the reservoir to the point of sale. In practice, it is the work of understanding what can slow or stop the flow of produced fluids, from the rock near the well, up the tubing, through flowlines and pipelines, to separation and storage, and of preventing or fixing those problems.
Flow assurance began as a specialty in deepwater production, where cold seafloor temperatures and long subsea lines make blockages costly and hard to reach. The same principles apply to onshore wells, gathering systems and facilities.
Main flow assurance threats
| Threat | What happens | Typical triggers |
|---|---|---|
| Paraffin deposition | Wax crystallizes and coats surfaces | Oil cooling below its wax appearance temperature |
| Asphaltenes | Heavy oil components precipitate and stick | Pressure drop, gas injection, mixing oils |
| Mineral scale | Inorganic salts crystallize from water | Pressure and temperature changes, mixing incompatible waters |
| Gas hydrates | Ice-like solids of water and gas | High pressure and low temperature |
| Emulsions | Oil and water form stable mixtures | Shear through chokes and pumps, natural stabilizers in oil |
| Corrosion | Metal loss in pipes and equipment | Water, carbon dioxide, hydrogen sulfide, bacteria |
| Solids and sludge | Sand, fines and mixed deposits accumulate | Formation fines, corrosion products, iron sulfide |
These threats often interact. Asphaltenes stabilize emulsions, corrosion products seed deposits, and mixed organic and inorganic deposits are common.
Prevention and remediation
Flow assurance combines design, operations and chemistry:
- Design. Insulating or heating lines, sizing equipment, and choosing operating pressures and temperatures that keep fluids stable.
- Chemical prevention. Continuous or periodic injection of inhibitors: wax inhibitors, asphaltene inhibitors, scale inhibitors, corrosion inhibitors, hydrate inhibitors and demulsifiers.
- Remediation. Removing deposits once they form, with heat, solvents, dispersants, acids, mechanical tools and pigging.
- Monitoring. Tracking pressures, temperatures, production rates and fluid samples to catch problems early.
Remediation often means stopping production, so operators weigh the cost of prevention against the cost of lost production and intervention. Flow assurance chemicals make up a large share of oilfield chemicals.
Flow assurance at Locus
Locus describes its biosurfactant flow assurance products, Avert, AssurClean and FloBoost, as dispersing paraffin, asphaltene, sludge and solids and keeping them suspended to maintain throughput and reduce downtime.
Frequently asked questions
Wax (paraffin), asphaltenes, mineral scale, gas hydrates, emulsions, corrosion and solids. Which dominate depends on the oil, the water, the pressure and temperature path, and the system design.
No. It is most visible in deepwater, where interventions are expensive, but onshore wells, gathering lines, tanks and facilities face the same deposit, emulsion and corrosion problems.
They overlap heavily. Production chemistry is the use of chemicals to solve production problems, many of which are flow assurance problems. Flow assurance also includes system design, thermal management and operating strategy.
Sources
- flow assurance, SLB Energy Glossary
- Flow assurance, SPE PetroWiki