An operator in the Norwegian North Sea required a simple, low cost method of creating a dual lateral well design in order to access reserves which would otherwise have been uneconomical to recover. The well was located in a chalk reservoir and severe chalk influx had previously been experienced.
A multilateral solution, selected by the operator, was required to ensure the risk of losing the main target was as low as reasonably possible (ALARP), as well as being realistic and cost-efficient.
The traditional approach
The traditional solution to avoid severe chalk influx is to use proppant fracturing in order to stabilise the chalk formation. Typically, this is achieved by utilising coil tubing and stimulation sleeves to pump several frack stages. This approach requires access to both laterals and normally would necessitate a TAML level 4 or 5 junction.
The problem with the use of either of these approaches in this project was that the cost of a level 4 or 5 junction would have rendered the project uneconomical, so a new solution needed to be developed.
Marwell’s “well-first” thinking
Developing a simple and cost-efficient lateral drain hole offered an ability to boost project economics by facilitating early production from the lateral, prior to stimulating the main target, with no intervention needed in the lateral.
As an industry first, the lateral was completed with solids control screens designed in collaboration with HP Well Screen to prevent severe chalk influx. The chosen liner top/hanger in the lateral was a new and novel high-strength carbon fibre composite liner top. This material was selected because it has a very high collapse strength, which helps to mitigate the risk of the open hole junction collapsing.
During planning of the completion design it was identified that successful installation of the solids control screens in the lateral was a key risk. In order to reduce drag forces as much as possible Marwell identified Maxwell Oil Tools’ MCC centralizers as a critical requirement in order to reach total depth successfully. These bonded-to-pipe centralizers are constructed from composite materials and offer exceptionally low friction factors which were ideally suited to this application.
A modified flow control sleeve using dissolvable material technology was placed in the mainbore across the junction. This allowed for production from the lateral without the need for coil tubing intervention. Once it opened, the sleeve allowed for start-up of early production when the FADE material dissolved.
Launched in 2020, FADE is a family of dissolvable metal alloys and thermoplastic materials that dissolve or degrade when coming in to contact with common wellbore fluids, including fresh water, brine, oil-based mud and acid. The FADE material used was Marwell’s FADE100.
FADE allows for temporary construction in the well and was designed to disappear within hours, or days, when in contact with the appropriate fluid. This simple solution leads to reduced costs, improved safety, and lower emissions. FADE is the first product to be developed in-house by Marwell’s team of engineers and scientists.
The project is still ongoing with a stimulation date for the main bore taking place this summer. When this occurs, the sleeve to the lateral will be closed and re-opened for production from both drainholes.
Marwell was successful in delivering a completion design that fulfilled the well objectives and mitigated the risks. The dual lateral completion was successfully installed in the well, awaiting production start-up.
This cost-efficient completion design opens an opportunity for faster and less complex multilateral technology, aiding to access reserves that were not economically feasible with more conventional solutions.
Such a straightforward and novel completion design can be employed to tap normally uneconomic resources and extend the life of mature fields. While the final stages of the project are still ongoing, it is estimated that the likely upside for the operator will be several million dollars.
Marwell’s product portfolio
Specialising in wellbore construction and completion, Marwell collaborates with leading suppliers and service companies to offer tailored solutions that are not available elsewhere. The company has four strategic partnerships in place, including Maxwell Oil Tools, HP Well Screens, Metrol and Downhole Products and its key products include composite centralizers, standard centralizers, sand control and downhole monitoring.
Marwell’s expert engineering team further develops these field proven technologies to deliver a unique solution for a given well. Marwell also has a range of in-house products, including its FADE family of dissolvables and its FLEX range of carbon fibre products.
Mike Williamson, cited as the inventor on several patents, has played a key role in bringing new technologies into the market. His forward-thinking drive to improve on current methods is coupled with experience in oilfield services, having previously served as MDof a Norwegian oilfield service company. Through this and his work with Halliburton, he is seasoned in sales management, specialising in cementing operations.