The US Outer Continental Shelf holds an estimated 66.6-115.13 billion bbl of crude oil and 362.4-565.87 trillion cubic feet of natural gas, the US Department of the Interior said as it began regional OCS meetings on Apr. 6. But the figures contain significant data gaps, it added.
The estimates of technically recoverable reserves were based on a regional assessment of the entire OCS which the US Minerals Management Service completed in 2006 as well as assessments of new areas identified for inclusion in the 2010-15 draft proposed five-year OCS leasing program. The range was from estimates of a 95% probability on the low end to a 5% probability at the high end.
The numbers should be considered general indicators and predictors of actual oil and gas potential in the areas, according to the report which MMS developed in response to a Feb. 10 order by US Interior Secretary Ken Salazar.
It noted that new areas in the Atlantic, Eastern Gulf of Mexico, Pacific and Alaska OCS have been identified for inclusion in the draft proposed five-year oil and gas program which Salazar delayed by adding six months to the public comment period and broadening its scope to include renewable and alternative energy sources. He also scheduled public meetings in each of the four OCS planning areas during April to get new information.
"Although leasing has not occurred in these areas for about 25 years, previous exploration has occurred in portions of these areas and some contain active leases with producing oil and gas fields. Updated research and exploration regarding the likely location of energy resources and environmental impacts are necessary to fill in data gaps," the report said. It also described several important environmental and safety questions which will need to be addressed.
Hydrocarbon endowment
MMS undertook the 2006 OCS assessment under a provision of the 2005 Energy Policy Act. Under that assessment, mean estimates of the total OCS hydrocarbon endowment were 115.4 billion bbl of oil and 633.6 Tcf of gas, or a total of 228.2 billion bbl of oil equivalent (BOE). More than 18% has been produced already and another 11% is contained within various resource categories which represent near-term and mid-term production, it said.
"Notably, even after more than 50 years of exploration and development on the OCS, 70% of the mean BOE total endowment is represented by undiscovered resources. More than half of this potential exists in areas of the OCS outside of the Central and Western Gulf of Mexico," the report noted.
Of the estimated undiscovered technically recoverable resources on the OCS, the largest amounts are in the Gulf of Mexico (41.21-49.11 billion bbl of oil and 218.83-249.08 Tcf of gas) and offshore Alaska (8.66-55.14 billion bbl and 48.28-279.62 Tcf), according to the 2006 assessment.
For the 2010-15 draft proposed program, estimated economically recoverable resources under prices of $60/bbl and $6.41/Mcf totaled 52.16 billion bbl and 200.85 Tcf. The amounts rose to 64.85 billion bbl and 270.43 Tcf under prices of $110.74/bbl and $11.74/Mcf, and 70.79 billion bbl and 307.04 Tcf under prices of $160/bbl and $17.08/Mcf.
The report also examined potential contributions from wind, wave and tidal energy operations on the OCS. It said that the Atlantic OCS has the greatest renewable energy potential of the four planning areas, with offshore wind power likeliest to make a substantial contribution in the next 5-7 years.
Atlantic concentration
"Substantial wind resources exist offshore the Atlantic Coast, near high-energy demand centers. Strong wind resources also exist offshore California, Oregon, Washington and Hawaii, but it appears that the majority of this resources likes in deep waters where technology constraints are potentially significant," it said.
Alaska also has ocean areas with outstanding renewable energy resource potential, but they are not expect to be developed in the near term because of harsh weather conditions and their significant distance from high-energy demand centers, the report added.
It also identified several safety and environmental factors which potentially could restrict OCS energy development. It listed oil spills as a major concern but said that spill prevention efforts through required, extensive safety procedures and practices and engineering requirements such as downhole shutoff valves and blowout prevention devices apparently are effective.
Understanding sea floor habitats will be important in considering leasing decisions for renewable as well as traditional energy resource development, the report said. Some information already has been gathered, but there are significant data gaps for a number of areas, it indicated.
"In some cases, exploration seismic surveys for oil and gas production, followed by required site-specific high-resolution 'hazard' surveys, could provide detailed information about the seabed with regard to drilling hazards as well as for evaluating benthic habitats. In other cases, additional detailed, high-resolution mapping may be necessary along with ground-truthing with sediment samples, remotely operated vehicles or even submersibles in order to verify community makeup to allow for mitigation and avoidance of habitats," it said.
Coastal impacts
The report also cited coastal impacts ranging from wetland losses associated with onshore energy infrastructure along the US Gulf Coast to heavily developed or protected Pacific Coast areas which reduce options for pipelines or utility corridors to support shore-based construction.
"While there are refineries and ports capable of supporting heavy industry, for the most part the Atlantic region lacks existing onshore infrastructure geared to supporting offshore activity. Additionally, a significant portion of the coast, except portions of South Carolina and Georgia, are either developed or are state or federally protected shorelines," it said.
Potential oil and gas impacts on fisheries range from damage caused by accidental oil spills to space-use conflicts, habitat alterations and seismic surveys, according to the report. "Key challenges for renewable energy development common to all OCS areas include offshore space-use conflicts, artificial reef effects, habitat alteration, noise from pile driving and effects from electromagnetic fields," it said.
In addition to seismic surveys which will be necessary to close gaps in OCS oil and gas resource evaluation, the report said that offshore renewable energy technologies are still developing and standardized protocols and technical design criteria are needed.
"The experience, knowledge and tools exist to ensure that offshore energy development is developed in a comprehensive and environmentally sound manner. By obtaining stakeholder input (locally and nationally), compiling existing information and acquiring new data where needed, conducting objective analyses using monitoring data to manage adaptively, and applying the necessary mitigations and safeguards along the way, we can achieve our national energy, economic and environmental goals," it said.
Contact Nick Snow at [email protected]