What's new in production

	Vol. 225 No. 5
ROBERT E. SNYDER, EXECUTIVE ENGINEERING EDITOR

CO₂-based EOR in the UK. A Department of Trade and Industry (DTI) report, "Implementing a demonstration of Enhanced Oil Recovery (EOR) using carbon dioxide," was published in early April. The report fulfills DTI's commitment in the Energy White Paper to "set up an urgent detailed implementation plan with developers and oil producers to establish what needs to be done to get a demonstration project going."

The main conclusions from the report are: 1) under existing current market conditions, there is little interest in CO₂-based EOR among North Sea oil producers; consequently, a full implementation plan has not been developed; 2) CO₂-based EOR remains a potential option for demonstrating carbon dioxide capture and storage (CCS), which is central to development of near-zero emissions fossil fuel combustion plants; and 3) DTI is reviewing its strategy for development of a near-zero emission fossil fuel plant, and CO₂-based EOR will be further considered within this strategy.

Recognizing the potential value of CO₂-based EOR as a way to demonstrate CCS, the report specifies a set of interim actions to take the concept forward for possible inclusion in the overall strategy. One EOR technique involves injecting CO₂ into the oil reservoir, which reduces crude viscosity, hence making it easier to extract. The technique is used widely in North America, but has not been deployed offshore.

CCS is attracting much international interest as a technique for making major reductions in CO₂ greenhouse gas emissions while continuing to use fossil fuels. The main option for storing CO₂ is through geo-sequestration in oil reservoirs, depleted gas fields and saline aquifers. Sequestration in oil fields, combined with EOR, offers a financial return to partially offset the cost of CCS.

The commitment in the Energy White Paper to set up an implementation plan for CO₂-based EOR was motivated by preliminary results that suggested this could be economically attractive with some North Sea oil fields. However, further assessments reported in DTI's Review of the Feasibility of CCS in the UK confirmed that CO₂-based EOR is not yet an attractive investment to North Sea oil producers. However, it could have a role in any future demonstration of CCS, hence its inclusion in DTI's review of its strategy for development of near-zero emission fossil fuel technologies.

Canadian coalbed methane. Canada has significant CBM potential, the majority of which is in Alberta. The Alberta government recently announced, as part of its 2004 – 2005 fiscal year budget, an initiative to encourage development of the province's vast resources to help offset declining gas production, which Lehman Brothers estimates was down 3.5% to 4% in 2003. While CBM production in Canada is in its infancy, CBM production has been well established in the US for over a decade, and it now accounts for about 8% of total US gas production.

Interest in Canadian CBM opportunities has increased over the past several years as returns on conventional gas drilling opportunities have decreased. These opportunities are believed to have the potential to double proved gas reserves in Canada and add over 3 Bcfd, 15%, to total Canadian gas production.

The Canadian Society for Unconventional Gas (CSUG) estimates that there is 182 Tcf to 553 Tcf gas in place within Canada's coal seams. Some 20 Tcf to 60 Tcf of this is believed to be recoverable, and roughly 75% is estimated to be located in Alberta. CBM production in Canada accounted for 35 MMcfd, or far less than 1% of total 2003 Canadian production of 16.8 Bcfd. The Albertan government will examine whether to improve fiscal and tax regimes for CBM development to encourage development. For more information, a contact is: Thomas Driscoll; tdrisco@lehman.com.

Reducing vortex-induced vibration (VIV). Shell Global Solutions (US) Inc. (SGS) has successfully completed industry's first replacement of VIV helical strakes with patented ROV retro-fit fairings along a 595-ft stretch of catenary pipeline riser on Murphy Oil Corp.'s Medusa SPAR, located at 2,250-ft water depth in the Gulf of Mexico. By combining the patented RIVET NB VIV suppression fairing installation and helical strake removal tooling developed by SGS, the replacement took just 24 days, including mob/demob. This deepwater catenary riser retrofit is an efficient method for replacing high-drag helical strakes with lower-drag fairing-style VIV suppression devices.

The installation system adapts to different diameter fairings to accommodate a wide range of pipeline sizes. The compact system requires relatively little deck space, which allows use of small offshore construction vessels or minimal deck space on an existing structure. The system is mated to the ROV remotely, while subsea. Also developed for the project was a set of strake removal tools that can accommodate any size to be removed.

This new technology can significantly reduce deepwater pipeline costs by reducing the over-design needed to accommodate high drag and vibratory loads. When installed for stabilization of horizontal spans, it can also eliminate circuitous pipeline routes around subsea canyons and steep slopes, saving time and money. Shell Global Solutions is made up of seven independent technology companies within the Royal Dutch/Shell Group of companies.

Predicting waves 30 sec. away. Exeter University, in Devon, UK, with a project team including researchers from Imperial College, Southampton, Bath and Edinburgh universities, is developing a sophisticated device based on an optical scanning radar called LIDAR (Light Detection and Ranging), which could allow oil companies to carry out difficult operations in periods of calm, preventing costly delays.

Deep-sea operators still lack a precise knowledge of what the rogue sea is going to do next. Now that is changing; the DSWP (Deterministic Sea Wave Prediction) system in the UK uses LIDAR to remotely/ continuously measure height and spatial profile of waves about one kilometer away from an oil rig or ship. From these measurements, it is possible to calculate, using special algorithms, the size of waves to arrive at the vessel. This provides the operators about 30 sec. advance notice. This seemingly short notice could help helicopters land, or time "tricky" operations like coupling supply lines to shuttle tankers. A Web contact is: www.exeter.ac.uk.