Driller spearheads effort to baseline greenhouse gases

July 12, 2004
Driller spearheads effort to baseline greenhouse gases Drilling contractors can play an important role in eliminating redundant measurement and reporting carbon emissions from drilling operations.

Drilling contractors can play an important role in eliminating redundant measurement and reporting carbon emissions from drilling operations.

Noble Corp. recently became the first offshore drilling contractor to join the US Environmental Protection Agency (EPA) "Climate Leaders" program. As a member of this voluntary partnership, the company will work with the government to develop the drilling industry standard to account for and manage greenhouse gases.

Joining this program follows Noble's completion of a 3-year base line inventory of greenhouse gas emissions from its drilling units worldwide. The inventory identifies the sources of virtually all Noble's greenhouse gas emissions and paves the way for the company to work with the EPA to develop programs to reduce these emissions.1

Creating the base line inventory and developing emissions-reductions programs are part of Noble's overall strategy continuously to improve its environmental performance. The company seeks continuous improvements, both to maintain ISO 14001 certification on 40 drilling units and facilities and to pursue certification for additional assets.

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All the company's environmental performance improvement initiatives are aimed at reducing the impact of Noble's operations on the environment. Noble's practice is to be proactive, act voluntarily, surpass regulatory compliance, and strive for meaningful disclosure of results.

Measuring, managing gases

Greenhouse gases have the ability to absorb heat in the earth's atmosphere, which in turn can warm the earth's atmosphere and surface. The main gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) that occur both naturally and as the result of human activity.

There is considerable discussion in the scientific community about the long-term effects of these emissions. Whatever the outcome of these discussions, Noble is committed to measuring, reporting, and managing the emission of greenhouse gases from its operations.

Noble also is proactively developing voluntary initiatives to measure, manage, and mitigate its emissions of nitrogen oxide, sulfur dioxide, carbon monoxide, and total unburned hydrocarbons. These gases, known as criteria pollutants, contribute to smog and pollution.

Marine diesel engines generate the electricity for an offshore rig's drilling equipment and accommodations (Fig. 2). Photo from Noble Corp.
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Identifying emission sources

The initiative to establish a fleet-wide base line of greenhouse gas emissions started with a pilot project aboard the Noble Earl Frederickson, a jack up rig working in the Gulf of Mexico. Under the direction of Noble's environmental steering committee, Trinity Consultants Inc. quantified the annual greenhouse gas emissions from the Noble Earl Frederickson.

The pilot inventory measured emissions from diesel-powered equipment, including the main engine and emergency generators. The measurements included actual emissions of CO2, CH4, N2O, and criteria pollutants directly emitted from significant rig sources for 2000 and 2001. Using equipment specifications, the analysis calculated greenhouse gas emissions for these years and then converted to CO2 equivalents, the accepted reporting measure for greenhouse gas emissions (Fig. 1).

At the conclusion of the pilot study, Det Norske Veritas (DNV) audited and evaluated the pilot test and procedures involved in collecting and tabulating Noble's diesel fuel consumption. DNV's work confirmed Noble's assumption that more than 99% of its emissions occur as a result of diesel engines operating to generate rig power (Fig. 2).

Creating the 3-year base line

Once the methods for collecting and measuring actual emissions and calculating estimated greenhouse gas emissions were verified, the company set out to establish a base line of greenhouse gas emissions for 2001-03.

Noble staff reviewed company records for the relevant years to determine the total diesel fuel consumption for its worldwide fleet of jack ups, submersibles, semisubmersibles, and drillships (Fig. 3). The initial goal was to create a 3-year base line of fuel consumption and greenhouse gas emissions based on "business as usual" operations; that is, operations that did not incorporate reduction programs.

During this time, Noble became aware of and sought out ChevronTexaco Corp.'s SANGEA emissions monitoring software. Many oil and gas companies use this software to calculate estimated greenhouse gas emissions. Noble, however, is the only drilling contractor that has used the software to create a base line for emissions.

Noble completed its base line inventory on Dec. 31, 2003. With these data in hand, the company can set targets for reducing the amount of greenhouse gases produced by its offshore drilling operations. Noble is evaluating methods to improve diesel engine efficiency and reduce its diesel consumption as a means of lowering emissions.

Voluntarily registering its emissions with the EPA climate leaders program is an important step forward in the company's greenhouse gas initiative. Noble is working to identify achievable reductions in greenhouse gas emissions for 2005.

Running diesel engines to power a moored semisubmersible, such as the Noble Amos Runner, shown operating in the Gulf of Mexico, can produce more than 12,000 tonnes of carbon dioxide annually (Fig. 3). Photo from Noble Corp.
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Sharing lessons learned

Completion of the 3-year base line for greenhouse gas emissions is one of many improvements Noble has made since its first mobile drilling unit became ISO 14001 certified in 2000.

ISO 14001 certification is the recognized global standard of excellence in environmental management and protection. Noble's ISO certified assets are audited regularly to ensure the company continuously improves their environmental performance.

The base line initiative confirmed one of the lessons Noble has learned from its continuous improvement efforts over the years: Doing the right thing for the environment causes more good things to happen.

Reducing its fuel consumption not only reduces emissions of greenhouse gases and other pollutants, it promotes a cleaner workplace and allows Noble to pass along fuel cost savings to its customers.

Other lessons learned include:

  • The drilling industry must lead the charge to reduce emissions. A measurable percentage of greenhouse gas emissions from upstream exploration and development are generated by drilling operations, so that it is the responsibility of drilling contractors to manage their operations in a way that lowers emissions.
  • The industry needs to work together to develop standard protocols for measuring and reporting greenhouse gas emissions. This will prevent drilling contractors and oil and gas companies from reporting the same emissions.
  • Drilling contractors and their customers can avoid wasting fuel and emitting greenhouse gases by effectively managing the power management systems on drilling rigs. They must manage power generation and distribution so that rigs have adequate and reliable power without unnecessary redundancy.

The data Noble has gathered about its operations and environmental performance offer many opportunities to reduce its impact on the environment. In turn, Noble's customers benefit because they also avoid reporting emissions that are generated by the company's drilling operations.

Reference

1. Cadigan, M., "Noble Corp., Sustainable Global Performance, Report 2003," http://www.noblecorp.com/SGP2003.pdf, April 2004.

The author

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Mike Cadigan (mcadigan@ noblecorp.com) is health, safety, environment, and quality (HSEQ) manager for Noble Drilling Services Inc. He has more than 9 years of experience in the oil industry and has held various HSEQ positions in Canada, Europe, and the US. Cadigan holds a bachelor of commerce from Memorial University in St. John's, Newfoundland.