DeltaTek: Saving rig time and optimising drilling operations in the North Sea

Special from DeltaTek

Saving rig time is the priority for DeltaTek and the company’s disruptive innovative Cure product range does just that
Saving rig time is the priority for DeltaTek and the company’s disruptive innovative Cure product range does just that (photo: DeltaTek)

Contending with remote and harsh environmental conditions, the challenges presented during offshore drilling can be significant and result in increased rig time and costs. To overcome these challenges, operators are looking for innovative solutions which can assist in optimising drilling operations by simultaneously increasing productive time and reducing costs.

The recent oil downturn immersed the industry into continuous rounds of cost cutting, with the effects felt throughout. It was a challenging time for operators and service providers alike, as companies reassessed operations to establish a leaner, more cost-efficient and sustainable way forward. The current global epidemic and low oil price threatens to send the industry back into a time we have only just recently emerged from.

Recognising the growing need for reductions in cost and risk, DeltaTek Global was launched in 2015 in response to the requirement for efficiently implemented, intelligent, cost-saving and risk-reducing products. The company went on to receive funding from the OGTC and Scottish Enterprise to support technology development and went from concept to deployment in less than 18 months, a timeline unheard of in the oil and gas industry.

SeaCure® is a completely mechanical system with no electronics or hydraulics, making it a robust and reliable technique for optimising cement jobs and saving rig time
SeaCure® is a completely mechanical system with no electronics or hydraulics, making it a robust and reliable technique for optimising cement jobs and saving rig time (photo: DeltaTek)

Enhancing Efficiency
Saving rig time is the priority for DeltaTek and the company’s disruptive innovative Cure product range does just that.

SeaCure, DeltaTek’s inaugural technology, is a pioneering subsea cementing system, delivering stabbed-in, inner string cementing for subsea wells; using drill pipe inside the casing to optimise cement jobs. The novel system provides a range of major cost and time benefits to drilling and field development operations.

SeaCure has been proven to be successful in saving rig time and reducing costs and has been deployed on 30% of UK North Sea wells during the first half of 2019. DeltaTek is constantly evaluating projects and looking at ways to make their systems even more efficient. The Cure line now includes CoreCure, QuikCure and ControlCure.

DeltaTek’s patented SeaCure system provides a method to physically attach and hydraulically seal the inner string to the float shoe which, after the cement job has been completed, allows the inner string to be safely disconnected and retrieved, eliminating the traditional shoe track. Eliminating the shoe track makes drilling out the next section much easier, compared to conventional poor boy inner string or subsurface release (SSR) plug cementing systems. Ultimately, resulting in considerable rig time savings.

SeaCure has been proven to save a considerable number of hours on the drill out for the subsequent section, depending on the particulars of the conventional shoe track design. The fastest drill out observed after a SeaCure job was only 6 minutes.

Rapid Cement Curing
SeaCure not only allows this inner-string method to be used subsea, it has the added benefit of allowing controlled post-cementing circulation inside the cemented casing. This allows circulation of heated fluids inside the casing (QuikCure), increasing the cement setting temperature environment and reducing cement curing time by up to 90%.

After the cement job is complete, the inner string is sealed off at the casing shoe via a dart or ball, and the burst disc at the end of the inner string is ruptured, allowing the inner string contents to be circulated out of the casing ID. At this stage, a heat sweep is circulated through the inner string to elevate the temperature inside the casing. For every 4.5° Celsius increase in temperature, the cement set time is halved.

QuikCure – circulation of heated fluids inside the casing increases the cement setting temperature environment and reducing cement curing time by up to 90%
QuikCure – circulation of heated fluids inside the casing increases the cement setting temperature environment and reducing cement curing time by up to 90% (photo: DeltaTek)

In one project conducted on 6 wells in the North Sea, DeltaTek utilised their SeaCure and QuikCure technology in an effort to reduce costs to the operator and optimise cement placement of the primary job.

SeaCure allowed DeltaTek to minimise the cement volume pumped and reduce total cement displacement to just 2.0 m3, ensuring reliable conductor cementing. Following SeaCure QuikCure circulated a +60° Celsius flush to each well, reducing wait on cement time by 70% versus offset wells.

Delivering foundations for each well, the SeaCure 20-inch shoes were drilled out in less than 20 minutes, delivering the project on budget and ultimately saving rig time across each well.

Using a wellbore heat transfer model and the SeaCure system with warm water circulation, DeltaTek was able to provide QuikCure to significantly reduce cement curing time. In the offshore drilling industry, where spread costs can be upward of USD 400,000 per day, QuikCure can save more than USD 200,000 per conductor operation, on top of the proven cost savings associated with the initial SeaCure service. For deepwater operations, where rig rates are exponentially higher, the potential savings are even greater.

Simulating and proving the process
Partnering with The School of Engineering at The University of Aberdeen to develop a simulation tool to model the heat transfer that occurs during the QuikCure process, SimCure was able to simulate and prove the economic and environmental benefits for the industry when utilising QuikCure.

During the project, the economic assessment of a subsea well campaign showed a new benefit to the operator of over USD 800,000 for the campaign and the environmental impact assessment indicated that the CO2 emissions of the project were reduced by 168 tonnes, as a result of using SeaCure and QuikCure.

DeltaTek has developed simple and robust technologies that are proven to result in considerable savings to the operator’s bottom line. The Cure service line has been extensively used across the North Sea and through Norwegian partner, GS Oil Tools, DeltaTek is bringing those same cost and rig time savings to the Norwegian North Sea.