Understanding potential pressure regimes in undrilled Labrador deep water by use of global analogues

Abstract

In recent years, new deepwater seismic-based exploration work has resulted in the revision of existing basin boundaries and identification of new, potentially oil-bearing basins in the deepwater Labrador region. The petroleum potential in this deepwater area has also been encouraged by the identification of slick and seepage locations using 2D seismic data and satellite imagery. The importance is that surface slicks possibly are related to subsurface hydrocarbon migration. Thus, all recent data collated together show strong evidence for an active petroleum system in deep water. Many of the wells in shallow water have been drilled with low mud weights, suggestive of low pore pressures. However, where thick shale packages are present, significant overpressure is observed by significant kicks. Clearly, there is a close association between thick (and deep) shale packages and high pore pressure. Thus, one of the key risks in developing the deepwater potential is to understand the pressure regime. The success of this approach has been highlighted recently by successful discoveries such as the presalt Lulu field onshore Brazil and associated discoveries in Gabon and Angola and postsalt discoveries that include Jubilee field offshore Ghana and the associated discovery of Zaedyus field in French Guiana. The deepwater Vøring Basin of the Mid-Norway North Sea and the Labrador slope and deep water share a similar passive margin setting to each other, similar facies associations, and structural development.