OTC 2014: Offshore construction goes deep

OTC 2014 Offshore construction goes deep
Castorone vessel (Image source: HGG Group)

Offshore Energy Today is sharing the following article with permission from OTC 2014.


By Deon Daugherty, Hart Energy

Although science fiction has depicted the deepest parts of the ocean as the domain of serpents and seahorses, the oil and gas industry is moving its offshore exploration to those unimagined depths.

During a Monday morning panel at OTC 2014 titled, “New Deepwater Construction Equipment Update 2014,” Roberto Faldini of Saipem Spa was the first speaker to explain the rigors of exploring those depths. He described the work behind his company’s pipelaying vessel, Castorone, which means “big beaver” in Italian, highlighting research from the paper “Castorone and FDS2: Getting Stronger for Laying Deeper.”

Jayesh Antani of Enbridge Offshore Pipelines LLC and Rene Raaijmakers with IHC Merwede served as cochairmen of the session, one of the first technical panels of OTC 2014.

“In the world of offshore installations, trunk lines and sea lines twist and turn like sea serpents at the bottom of the sea, carrying the payload of oil and gas to power a world hungrier [than] ever for energy,” Faldini wrote in the paper. “These ultradeep scenarios, unimaginable and out of reach just a few years ago, require the new generation of S- and J-laying vessels to be capable of applying pipe-holding tensions beyond 500 tonnes during normal operations, which may become twice or three times that value if the pipelines are unexpectedly flooded.” 

Such a situation requires a couple of clever ideas, he explained. Enter the Castorone and FDS2, two new deepwater-laying vessels.

Saipem determined that key elements of the work to exploit J-lay tower capacity would include using compliant grip pads, increasing the equivalent friction factor, and equalizing distribution and evening the spread of loads. The innovation required the equipment to use high-friction bars and an axial load to equalize clamping and to be adaptable. Several coating types also would be critical. And, the Castorone was equipped with a next-generation stringer capable of being adjusted during laying.

Andrea Oldani, a co-writer of the report who presented with Faldini, said during the panel that the work, especially the stinger, represented moving from “chaos to order.” The improved stinger has the ability to be adjusted for different pipe sizes and can be fully monitored. Accompanying the new technology was state-of-theart control and management software, Faldini and his team noted in their paper. This included a centralized management system, a ramp management system and pipelay guidance. Combined, these systems enabled the management team to remotely control the vessel firing line and present a unique approach to monitoring the pipe construction cycle onboard.

“These features make the new Castorone and the FDS2 unique and distinctive vessels on the pipeline installation market for steep-S, S-laying and J-laying technologies,” according to the paper.

From some of the larger vessels in the deepest water to one of the more specialized components, the panel moved to Mike Wilson of Ecosse Subsea Systems Ltd. Wilson described his role in offshore work, saying, “I’m a very small fish swimming in very deepwater.” 

Wilson explained that Ecosse’s SCAR Plough system is designed to deliver either all-in-one or a one-part solution to support trenching and pipelay and cable-lay operations. It’s high-risk and expensive work, but Wilson said the SCAR system is inherently simple and robust, which can mean reduced downtime and low maintenance costs.

The SCAR system operates in three key modes: boulder-clearing, trenching and backfill. It’s one of the few systems on the market that has the boulder-clearing capability, he said. What’s more, there is only one moving part on the entire machine, which Wilson said makes it extremely reliable. While clients typically want equipment that offers no risk, is ultra reliable and available at any time, construction companies such as Ecosse are working hard to deliver, Wilson said. The SCAR system was originally developed as a subsea plough, but it was redesigned to meet the needs on a seabed clearance scope on the Laggan-Tormore project west of Shetland for Total E&P Ltd. and DONG E&P Ltd.

There, the system was mobilized in six days to clear 67 km (42 miles) of 16-km (10-mile) routes during a six-day period.


 May 06, 2014