Strategic Environmental Assessment (SEA) in Offshore Oil or Gas Sector Development

By Syed Masiur Rahman
April 2005

The Author is Research Assistant at the King Fahd University of Petroleum & Minerals in Dhahran, Saudi Arabia. → See also:

Definition of SEA

SEA can be defined as ”the formalized, systematic and comprehensive process of evaluating the environmental impacts of a Policy, Plan or Program (PPP) and its alternatives, including the preparation of written report on the findings of that evaluation, and using the findings in publicly accountable decision-making”(Therivel et al. 1992). It is, in other words, the EIA of policies, plans and programs, keeping in mind that the process of evaluating environmental impacts at a strategic level is not necessarily the same as that at a project level. Noble (2000) suggested the following definition for SEA based on ”strategic” characteristics of it:

SEA is the proactive assessment of alternatives to proposed or existing PPPs, in the context of a broader vision, set of goals, or objectives to assess the likely outcomes of various means to select the best alternative(s) to reach desired ends.

SEA and Sustainability

The role of SEA is often related to sustainability objectives, such that SEA can assist the decision-making in improving the design of more sustainable policies and strategies (Noble and Storey, 2001). Consistent with the nature of a SEA system is its potential capacity to contribute to the achievement of sustainability aims (Partidario and Clark, 2000). SEA provides a framework by which the PPP is developed on a much broader set of perspectives including the comprehensive dimensions of sustainable development. SEA allows sustainability principles to ”trickle down” from policies and plans to individual development projects within a particular program. From an applied perspective, recent practice SEA is often related to sustainability goals, such that SEA can assist in the selection of more sustainable policies and strategies (Noble and Storey, 2001).

Impacts of Offshore Oil or Gas Development

In general, four phases of the offshore production process carry risks of environmental damage:

  1. during the preliminary seismic surveying of the potential resource
  2. during rig installation and drilling
  3. throughout hydrocarbon production
  4. in the course of transportation of the oil or natural gas.

(Rankin et al, 2001)

A general overview of potential environmental impacts of offshore oil and gas development is useful in order to understand the full scope of effects on the environment. The environmental impacts can be classified as chronic impacts expected from normal operations and acute impacts from serious accidents.

Direct environmental impacts associated with offshore oil or gas development usually include withdrawal of oil, gas, and condensate; introduction of chemicals, noise and vibration; solid and liquid sanitary and production waste; and habitat effects. Drilling wastes, which include spent mud and cuttings, cementing waste, produced fluids, process water, drainage wastewater, etc are the main pollution-contributors into the surrounding water.

The threat of a catastrophic accident - structural failure; blowouts; and process system ”upsets” such as fires and explosions are of greater concern than the chronic, operational impacts of offshore oil or gas development. Relatively small system anomalies can cause the catastrophic failure of complex human-machine systems. Structural failure of the offshore pipeline, the Floating Storage & Offloading (FSO) or the Single Anchor Leg Mooring (SALM) buoy could be caused by seismic events, extreme seas, sea ice, corrosion, steel failure, etc.

SEA Techniques and Methods

Techniques can be distinguished from methods in that techniques provide data; on the other hand, methods are concerned with the various aspects of assessment, such as the identification and description of likely impacts and the collection and classification of data (Barrow, 1997; Canter, 1996). According to Bisset (1988) techniques ”provide data which are then collated, arranged, presented and sometimes interpreted according to the organizational principles of the methods being used”. A large number of methods are available for assessing environmental impacts (see Petts, 1999). The characteristics of different methods contribute in the understanding of their interrelationships and the appropriateness of different methods in different applications.

There are several analytical features of the methods that need to be considered when several methods are used in combination (Finnveden and Moberg, submitted for publication):

  1. degree of site-specificity
  2. degree of time-specificity
  3. type of comparison
  4. degree of quantification
  5. system boundaries
  6. types of impacts and effects considered

Selected Environmental Impacts of Arctic Offshore Oil or Gas Development

Protection of the Arctic Marine Environment (PAME)´s Guidelines for Offshore Oil and Gas Development in the Arctic (2002), provide an overview of the potential impacts of offshore development in this environmentally sensitive region. Smith (2003) focused on a few, less well-covered aspects that are nonetheless essential to strategic consideration of oil and gas development in the region. The environmental aspects are as follows:

  1. Climate change
  2. Special characteristics of arctic marine and coastal ecosystems
  3. Onshore development
  4. Spills in ice-infested waters
  5. Impacts of sea floor pipelines

SEA in Oil or Gas Development, UK

The Department of Trade and Industry (DTI) recently has taken a policy decision that SEA will be undertaken prior to future wide-scale licensing of the UK Continental Shelf (UKCS) for oil and gas exploration and production. This decision implements the spirit of the EU Strategic Environmental Assessment Directive. In preparation for the 19th licensing round the DTI conducted a sectoral SEA of an offshore area known as ”White Zone”, a boundary area between the UK and the Faeroe Islands. Based on the ”White Zone” SEA experience, the DTI proposes to follow a process for subsequent pre-licensing SEAs.

Offshore Oil and Gas, and Environmental Assessment in Canada

An independent scientific panel was appointed in 2001 by British Columbia to examine whether offshore oil and gas can be extracted in a scientifically sound and environmentally responsible manner. In 2002, the panel concluded that ”there is no inherent or fundamental inadequacy of the science or technology, properly applied in an appropriate regulatory framework, to justify a blanket moratorium on offshore oil and gas activities.” The panel and a task force made a number of recommendations of prerequisite further works before any activity begins. In response, the University of Northern British Columbia (UNBC) was enlisted by the province to carry out scientific and technical research and develop a work plan that responds to these recommendations.

The successful environmental assessment of the Sable Island Gas Fields in Atlantic Canada took place with the cooperation between federal and provincial governments. The involved federal departments pursued a coordinated environmental assessment with all the jurisdictions involved, thus harmonizing the review process. Given the role of the National Energy Board, a review panel was structured along the lines of a quasi-judicial body and included formal hearings, swearing of witnesses and other functions of a regular quasi-judicial body. The joint review report was released in October 1997. Each of the regulatory agencies having jurisdiction in the project gave their approval after adopting a number of recommendations outlined in the panel report.

In Canada, the exploration and production of oil and natural gas permitting process is accomplished through licenses and authorizations issued by the National Energy Board, annually renewable. The application of SEA to the oil industry is accounted to the Councils of the Provinces (Canada - Nova Scotia, Newfoundland and Labrador Offshore Petroleum Board), promoting agents and regulators, responsible for the environmental protection throughout the whole phases of the offshore activities, from exploration to decommissioning (Rovere et al., 2002).


One of the main difficulties experienced in most countries in relation to adoption and operationalization of SEA is the lack of appropriate methodologies and lack of consistency in application. SEA guidance often refers to Environmental Impact Assessment (EIA)-type analyses but it is often difficult to use the methods associated with EIA in SEA because they are adjusted for site-specific information and local impacts whereas SEA often is not site-specific and can often be primarily concerned with cumulative and indirect impacts. There are a number of publications on SEA process which differ on steps but they possess almost same main features. It is now established in the literature that there is no single ”best” methodology for conducting a strategic environmental assessment of a policy, plan or program proposal. In Canada, federal departments and agencies are encouraged to apply appropriate frameworks or techniques, and to develop approaches tailored to their particular needs and circumstances.



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