TECHNOLOGY FROM EUROPE

New automated rig gaining acceptance

RamRig is a highly flexible concept for drilling and workover packages developed by Aker’s Maritime Hydraulics. It is being used for both fixed and floating installations and is available as single-, double- or triple-stand rigs with 150- to 1,000-t capacities. Its main features are: 1) lower weight and cost, greater efficiency and improved safety; 2) reduced operational costs in manning, maintenance and energy consumption; and 3) integrated, long-stroke, active / passive heave compensation with optimal weight-on-bit control. The company’s latest delivery is for Snorre B platform in the North Sea.

Rollout of Maritime Hydraulics’ latest RamRig.

Operating on a floater. Even though the rig had already been proven on the Oseberg East platform, it had not been used on a floating drilling unit. After a comprehensive testing period, conversion of the Bideford Dolphin semisubmersible to a state-of-the-art, fully automated drilling rig was completed in May 1999. This RamRig – the company’s second – is drilling in the Tampen area offshore Norway. It is operated by Dolphin Drilling on a long-term contract for Saga Petroleum.

The drilling system fully complies with strict Norwegian regulations as to safety and remote operation of drilling equipment. The fundamental difference between fixed- and floating-platform operation is, of course, the drillstring-compensation system. The automated rig does not include conventional compensating equipment. Instead, it uses hydraulically operated rams as a combined hoisting and compensating system (active, as well as passive). Thus, drilling operations from Bideford Dolphin are regarded as the ultimate test for this technology.

Bideford Dolphin’s learning curve. Rig manager Terje Tjelta commented, "This automated-rig concept gives better control and accuracy of drilling operations. Examples are tripping, where automated and improved control systems give reduced probability of tight-hole / stuck-pipe problems. Soft-torque and auto-drill functions give better bit control, resulting in improved ROP, better deviation control in wells and a smoother, more direct wellbore.

"Traditional drill-crew tasks during operations were reduced. During startup, the crew was used for extra supervision / maintenance. There is a potential for permanently less manpower after the startup phase. Remote-operated / controlled pipe handling works very well and is superior to other remotely operated pipe-handling systems I have worked with."

Better understanding of this new drilling concept is the biggest challenge. Teaching personnel how to take advantage of improved control systems, data acquisition, automatic monitoring and drilling functions – and to use these tools to analyze and improve drilling efficiency and control – is critical to optimizing the design’s performance potential.

The seventh RamRig. The Snorre B project has focused on transferring design, operation and maintenance experiences from earlier projects, especially Oseberg East and Bideford Dolphin. When combined with meeting all milestones throughout the project, project management feels confident that the rig will be delivered with optimal function and quality.

About 800 t of high technology equipment was moved out of the workshop on December 28, 1999; scheduled delivery is in April 2000. MH project manager Bjørn Gundersen said, "We are very satisfied with progress of the project. Delivery on time with the agreed quality has been one of the main success criteria for these projects.

"Our top vision is to regain confidence from the marketplace to the concept. We have had wide-open and good communication channels to our other RamRig projects, with frequent follow-up of our own database and examination of audit reports."