From Ordovician Source Rock to Dolomitized Devonian Limestones:

A Promising Exploration Model in Gaspésie, Eastern Canada*

Jean-Sébastien Marcil¹, Jean-Yves-Lavoie¹, Valérie Lavoie¹, and Virginie Lavoie¹

Search and Discovery Article #10089 (2005)

Posted August 14, 2005

*Oral presentation at AAPG Annual Convention, with SEPM, Calgary, Alberta, June 19-22, 2005.

Click to view presentation in PDF format.

¹JUNEX Inc., 3075, Quatre-Bourgeois, Suite 103, Quebec City ([email protected])

Abstract

Gaspésie is a 20,000 km² peninsula located in the southeastern part of Province of Quebec. Galt field is the only active hydrocarbon production but several seepages in the Devonian Sandstone are known. Recent exploration activities revealed a new potential for the area. JUNEX has been very active in the Peninsula and has been able to constrain an innovative exploration model.

Based on source rocks and thermal maturation studies, an Ordovician marine black-shales origin is given for the oil found. Analysis yield values ranging from 4 to 10% TOC with initial hydrocarbon potential up to 100 kg HC by ton of rock. This Ordovician oil migrates along the regional extensional faults and feed the younger reservoir zones.Surface core sampling and outcrop studies reveal a good reservoir potential for Silurian reefs, hydrothermal breccias, and Devonian sandstones. In the three wells completed by JUNEX : oil, gas, condensate and HTD were discovered. According to the re-evaluation of the 2000 km seismic data coverage, together with two high-resolution aeromagnetic surveys, new exploration model focuses on the high potential of hydrothermal reservoir related to strike-slip faulting over a Silurian-aged extensional basin and shallow stratigraphic traps in the Devonian-aged deltaic fans or channels.