简介：本文主要介绍了2008年在海上勘探开发领域的技术动向，例如：提高钻机性能、海上油气开发取得的成功、环境方面的技术进步等。

New technology takes projects deeper 

The move to deeper water was one of the primary drivers behind a number of milestones reached in 2008. Noteworthy records were set across the board in the offshore segment of the industry, from deepwater mooring to advances in subsea systems to classification of new production systems. 

Cameron supplied the world’s first all-electric subsea production system, including the CameronDC all-electric tree (pictured here), for Total’s K5F development in the Dutch Sector of the North Sea, which came onstream in September. (Image courtesy of Cameron)

Offshore E&P activities stepped up this year, the result of a cash injection that put nearly all of the jackup and floater fleet to work around the globe. The boom brought with it opportunities to put new technologies to work. Companies that invested in R&D when the prospects for applying new advances were scarce finally got the openings they had been waiting for to show what their innovative solutions could achieve. 

Mooring advances go deep 

In a tight rig market, it is in the operators’ best interest to extend the drilling capability of rigs that are already onsite and under contract because pushing those limits can save a lot of time and money. 

One noteworthy instance of extending drilling depth capability was accomplished by InterMoor Inc., which worked with Murphy Sabah Oil Co. and partner Petronas Carigali in April to moor the Diamond Offshore Ocean Rover semisubmersible on the Buntal exploration well offshore East Malaysia. This project required two anchors to be set in more than 8,000 ft (2,438 m) of water, with the deepest leg of the eight-leg conventional mooring system reaching 8,430 ft (2,570 m). 

This “first” also required Solstad Offshore ASA to push the Normand Ivan and Normand Atlantic anchor-handling vessels (AHVs) to limits they had never previously achieved. The AHVs installed eight 10-metric-ton Stevpris anchors using the rig’s self-contained wire and chain. 

Another interesting mooring milestone was the introduction of an improved anchor, the OMNI-Max, winner of one of the 2008 Offshore Technology Conference Spotlight on Technology awards. Developed by Delmar Systems Inc., the OMNI-Max anchor is a gravity-installed vertically loaded anchor (VLA) for mooring mobile offshore drilling units (MODUs). The anchor can be loaded in any direction, 360º around the axis of the anchor. 

The first OMNI-Max anchor was installed on Garden Banks Block 667 in the Gulf of Mexico (GoM) in Dec. 2007. Edison Chouest’s anchor-handling tug and supply vessel Alex Chouest deployed and pull tested the anchor. The anchor line was later connected to Diamond Offshore Ocean Star semisubmersible using Delmar’s patented subsea mooring connector, which connected the preset mooring line to the rig’s self-contained mooring components. 

The same connectors have been selected by Murphy Oil Co. for the world’s first floating production, drilling, storage, and offloading (FPDSO) vessel for the Azurite field in the Mer Profonde Sud Block offshore Republic of Congo. 

The FPDSO, which was originally scheduled for installation late this year, will work in 4,593 ft (1,400 m) water depth. This connector technology is used for MODUs and permanent mooring installations to allow single-vessel deployment of anchors and mooring lines. 

Subsea successes 

Subsea production technology expanded into India in 2008. 

In late September, Reliance Industries Ltd. saw first oil from the MA-D6 field in the Bay of Bengal. The record-breaking project produced first oil via technology supplied by Aker Solutions, which delivered a complete subsea production system and managed the installation of the subsea equipment. Aker Floating Production converted and delivered the Dhirubai 1 floating, production, storage, and offloading (FPSO) vessel. Aker Solutions was also responsible for the process equipment and a mooring and offloading system for the FPSO. 

In another first in the same month, Cameron deployed its first all-electric subsea production system, CameronDC, on Total’s K5F project in the Dutch Sector of the North Sea. This unique system is powered by direct current. It has no batteries, hydraulics, or accumulators, and much of the conventional electro-hydraulic equipment has been simplified or eliminated. 

In October, UK companies AGR Field Operations and flexlife Ltd. formed a partnership to provide a new subsea application that helps prevent failure in flexible risers and flexible flowlines. Aberdeen-based flexlife devised a unit that can scan a flexible riser in situ to detect annulus flooding anywhere along its length, while AGR Field Operations has the remotely operated vehicle capability to deliver the service through the Neptune system, which can work to 19,680 ft (6,000 m) water depth. 

Also in October, Helix Well Ops’ Asia-Pacific team set a world depth record for subsea wireline intervention from a monohull vessel by retrieving tubing hanger plugs from two subsea wells located 82 ft (25 m) apart in 1,286 ft (392 m) of water. The retrieval was accomplished from Havila Shipping ASA’s Havila Harmony multipurpose vessel on the first of the two trees after both had been landed on their wellheads using the company’s Vessel Deployment System (VDS) and Subsea Intervention Device (SID). The VDS can work over a moonpool or create an over-the-stern moonpool work area on any vessel that allows the deployment of guidelines, podlines, lubricator, and subsea equipment packages. The SID is a modular subsea lubricator that enables rigless intervention into subsea wells. 

Vessel news 

ABS had a busy 2008, introducing new structural requirements for analyzing FPSOs and revising the society’s “Guide for Floating Production Installations.” 

The group also developed an offshore structural assessment program specifically designed for semisubmersible drilling rigs. The ABS Eagle Offshore Structure Assessment Program allows designers to more easily check their designs against the ABS MODU Rules to confirm they meet classification requirements. 

A renewed interest in floating concepts for handling stranded gas led to additional milestones. ABS provided “approval in principal” (AIP) to a number of emerging proprietary technologies and transport designs that are intended to develop remote gas fields. There is interest in both compressed natural gas (CNG) carriers and floating liquefied natural gas (LNG) concepts. Nearly a dozen CNG projects are on the verge of commercialization, and ABS has granted AIP to all of the leading technical concepts developed for this sector. 

Floating LNG terminals are also in the works, evidenced by ABS granting an AIP to a concept proposed by Japan’s INPEX and another proposed by SBM Offshore. 

In other LNG news, Exxon Mobil Corp. moved the world’s first offshore LNG terminal to its final location off the Italian coast, where it will be capable of supplying about 10% of Italy’s natural gas requirements. 

Environmental advances 

StatoilHydro has long been an advocate of environmental responsibility, and two of the milestones this year reflect the company’s commitment to reducing carbon dioxide (CO2) emissions. 

Snøhvit, the first offshore development in the Barents Sea, has no surface installations, which makes it the first plant of its kind in Europe. Snøhvit is also the world’s northernmost LNG facility. In April, the field achieved another first with the start of carbon injection and storage. 

The CO2 from the Snøhvit wellstream is reinjected into the ground and stored in a formation beneath the gas-bearing formations on the field. Gas (containing 5-8% CO2) is piped from the field to an onshore plant on Melkøya Island, where the CO2 is separated from the natural gas and piped back to Snøhvit for storage. At full capacity, 700,000 metric tons of CO2 will be stored per year.
Another move to reduce emissions led in September to the approval of a novel approach to providing electricity for the Gjøa platform in the Norwegian North Sea. When the field comes onstream in 2010, it will be the first floating platform to get electricity from the mainland. According to StatoilHydro, this will mean a reduction in emissions to the environment of 250,000 metric tons of CO2 per year.