Developments in Flow Assurance
An uninterrupted flow of hydrocarbons plays an essential role in maintaining production volumes from oil and gas reserves.
Flow disruptions can prove to be both time consuming and costly. NNPC/Chevron Nigeria Limited Joint Venture recently awarded Saipem a contract to help it recoup 40,000 barrels per day of production, which was lost when damage to the flow barges system occurred.
Issues such as the build up of asphaltenes–which are the heaviest components of crude oils, wax–which amasses on cold surfaces of pipes, emulsions and gas hydrates, also have the potential to seriously impact on multiphase flow.
David Newman, global oil and gas sales and marketing director for Emerson Process Management, explained: "With operators needing to ensure that their oil and gas reservoirs are operating at the very peak of their potential, the successful and economic flow of hydrocarbons from the reservoir to the refinery has never been so important."
Integrated Approach to Oil and GasFlow Assurance
Flow assurance should be a key feature of any oil and gas project from the initial design stages. Xodus group recently announced that it has been commissioned to carry out two front end engineering and design (FEED) studies for the Juliet and Huntington fields in the North Sea.
Both FEED studies incorporate a comprehensive flow assurance assessment, as well as operational, safety and environmental risk reports. The company uses both steady-state and transient thermohydraulic analysis to help with flow assurance from newly developed fields and to optimise production from existing operations.
Pipe coatings can also play a role in flow assurance. Bredero Shaw is just one company producing insulated pipe coatings to prevent the build up of hydrates, which can present serious issues with flow efficiency.
The company has developed products for both above ground and subsea oil and gas pipelines, including those suitable for pipes that must withstand high temperatures.
Technology for Combating Flow Disruption
Emerson Process Management, an international production optimisation and reservoir management company, claims that oil and gas companies are facing increasing problems from the build up of hydrates.
Small blocks of hydrates, which are water molecules that have their cavities filled with gas, can be carried along by the flow, but when larger blocks are formed this can cause obstruction.
The company released the Roxar subsea Chemical Injection valve–a technology which it claims offers operators greater control over the levels of hydrate inhibitors that are added to the flow.
David Newman, global oil and gas sales and marketing director for Emerson Process Management, said that production optimisation is "why hydrate prevention is so high on the agenda today, especially with the rise in wet gas and deepwater fields which are more susceptible to hydrates."
The valve contains no moveable parts, which allows for a longer life, and no choke points–assisting in preventing clogging. In the event of a malfunction, the valve stays in place and will continue to provide a constant injection rate, allowing companies to prepare for replacement and maintenance, and minimising loss of production.
Wood Group Logging Services says that there is increasing demand for a non-chemical solution for hydrate blockages. The company created a Thermal Moderator Tool (TMT) capable of melting ice and paraffin blockages, and has previously been used to clear blockages offshore in West Africa.
John Paul Jones, president of Wood Group Logging Services, said: "The TMT was developed in response to requests from customers who wanted a non-chemical solution to eliminate hydrate blockages. It performed well in several test wells and is being used successfully in commercial operations, saving both time and money over traditional methods."