Nova Scotia, Morocco share geologic DNA
‘Analog Sisters’ Prompt New Ideas
The break-up of the supercontinent Pangea and the development of conjugate margins with analogous petroleum systems on opposite sides of the Central Atlantic have resulted in many past and present linkages between Nova Scotia and Morocco.
Geologists and geophysicists in Nova Scotia cite recent oil and gas discoveries in offshore Mauritania and Morocco as analogs for their sister discoveries offshore Nova Scotia, and vice versa. In order to “touch” the Late Jurassic carbonates at EnCana Corporation’s 1.0 Tcf natural gas discovery at Deep Panuke on the Scotian Shelf, geoscientists travel to Morocco, where analogous rocks outcrop.
Another historical linkage between Nova Scotia and Morocco is the French language – since the 1980s, Canadian government development agencies and universities have worked with French-speaking Moroccan geoscientists, transferring oil and gas technologies and exploration and production skills.
In association with the AAPG, geoscientists from Morocco and Nova Scotia organized two conjugate margin conferences featuring a series of field trips that showcase outcrops on opposite sides of the Central Atlantic.
The first conference, held recently in Morocco, designed to create Pan-Atlantic gatherings of geoscientists, facilitated the exchange of ideas on geological basin development and petroleum systems.
The second conference, set Aug. 13-15 in Halifax, Nova Scotia, will once again provide a venue for recent advances in seismic, drilling and production technologies specific to emerging plays in these frontier regions.
Given recent discoveries and the potential expiry in 2013 of exploration moratoria on the U.S. Atlantic Outer Continental Shelf and Canada’s Georges Bank, the oil and gas industry is revisiting these conjugate margins with renewed interest.
A Timely Conference
The upcoming August Central Atlantic Conjugate Margins Conference in Halifax, presented by the Canadian Association of Petroleum Geologists in association with AAPG, the Atlantic Geoscience Society and several other industry, academic and governmental sponsors, is titled “Sharing Ideas and Embracing Opportunities.”
The conference, to be held at Dalhousie University, will present three basic themes:
- Margin evolution and development.
- Basin petroleum systems.
- Productive fields and analogs.
In addition to the oral and poster sessions, organizers are creating a state-of-the-art seismic data room with the latest Central Atlantic Programs and profiles. The conference will include courses on salt tectonics and petroleum systems modeling, and a core workshop featuring wells from the Scotian Shelf and the adjacent U.S. Outer Continental Shelf.
Attendees will be able to view hydrothermal dolomites of the Late Jurassic Abenaki Formation in the cores from the Deep Panuke Field – during testing, the H-08 well flowed 50 to 57 Mmcf/d of natural gas.
Dave Brown, the conference co-chair, said the conference themes are extremely topical, given recent discoveries in offshore Nova Scotia.
“We have an active petroleum system, because wherever a reservoir was found, it was full of gas” said Brown, an AAPG member and senior petroleum geologist with the Canada-Nova Scotia Offshore Petroleum Board (CNSOPB).
Diving Into the Scotian Basin
Brown and his CNSOPB colleagues attended the conjugate margin conference in Marrakech, where they presented papers on the resource potential and exploration play types of the Scotian Basin, which measures about 100 to 150 kilometers wide and about 900 kilometers long.
Water depths there vary from less than 100 meters to 3,500 meters.
The shallow waters of the Scotian Basin – the historical focus of exploration – contain 194 wells, with historical oil production from the Cohasset-Panuke Field and current natural gas production from the Sable Project. To date, 10 Tcf of natural gas and 381 million barrels of oil have been discovered in the shallow waters of the Scotian Basin.
In 2006, the CNSOPB reported that another 17 Tcf of natural gas remained to be discovered in the Scotian Basin’s shallow waters. The CNSOPB’s report also estimated the resource potential of the Deep Water Scotian Shelf at 17 to 57 Tcf of natural gas and 1.3 to 4.5 billion barrels of oil.
An industry review of the recent drilling activity in the Deep Water Scotian Shelf revealed that the deepwater sediments – targeted by 10 wells – were not actually penetrated. According to Brown, the drilling data confirm the offshore delta is broader than previously thought and the deepwater turbidite sand reservoirs lie, undrilled, further down the slope.
Brown’s optimism about the deepwater prospectivity of the Scotian Shelf is further buoyed by recent analog discoveries in offshore Mauritania.
‘Something for Everyone’
Grant Wach, the Halifax conference co-chair and a professor of petroleum geoscience and director of energy at Dalhousie University, described Dalhousie as one of the leading academic institutions in the study of tectonics along the Central and North Atlantic conjugate margins.
According to Wach, an AAPG member, all of the technical sessions will run in one venue – there will be no concurrent sessions, thus enabling all participants to attend all the papers.
“There’ll be ample opportunity for academic geoscientists and industry explorationists to meet to exchange ideas,” he said. “There will be something for everyone, from geodynamic modeling to regional geology and reservoir geology.”
The Tide That Binds
Wach said the geology field trips have been planned with the tide charts in mind – that’s because Nova Scotia’s Bay of Fundy boasts the highest tides in the world, ranging up to 50 feet.
As such, many of the world-class outcrops can only be seen at low tide.
The Fundy Basin also is the largest and best-exposed early synrift basin in the Central Atlantic realm.
The pre-meeting field trips will include:
- The Permian to Jurassic rift successions.
- The Carboniferous section at Joggins, formed by salt withdrawal Cumberland Basin.
- The onshore Cretaceous reservoir equivalents of the production fields on the Scotian Shelf.
Post-meeting field trips will be led to:
- Morocco, to view the Triassic synrift reservoir facies and architecture.
- Portugal, to view the Jurassic carbonates and fluvio-deltaic successions in the Lusitania Basin.
Brown gets excited by the oil and gas potential of the virtually unexplored margin of North America.
“Imagine a carbonate bank fairway that extends several thousand kilometers from Nova Scotia, clear to Florida,” he said, “that’s been tested by only a handful of discovery wells at Deep Panuke and by two wells on the U.S. Outer Continental Shelf.”