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Last modified:
May 14, 2014

Oil Sands Caprock Integrity Project

Introduction

OSCRIP Study Area
OSCRIP study area (click to enlarge)

The Alberta Geological Survey (AGS) conducts a variety of studies on the rock formations that underlie Alberta, towards the goal of creating a strong scientific geological framework that will support regulatory process. The Landscapes and Geological Hazards Team conducts geological studies, the results of which can be used to help our understanding of formation behavior during hydrocarbon extraction processes and geological storage.

The AGS Oil Sands Caprock Integrity Project (OSCRIP) is a technical, scientific study related to geological mapping and characterization of units above and below bitumen zones.

Background

Alberta’s oil sands are one of the world’s largest known deposits of crude oil. Oil sands are a mixture of sand, clay, water, and bitumen. Bitumen is heavy crude oil, some of which is too viscous to flow freely. Depending on the depth at which the bitumen is deposited, it can be recovered by one of two methods: surface mining or in situ recovery. Surface mining is used when the bitumen is deposited at a shallow depth. Trucks and shovels excavate the oil sands and transport the deposits to extraction plants, where the bitumen is separated.
However, the vast majority of Alberta’s bitumen is too deep to be surface mined. About 80% of the province’s bitumen reserves can only be economically produced using in situ recovery. For thermal in situ recovery, a series of horizontal wells are drilled from a single well pad into the reservoir. Steam is injected to mobilize the bitumen and enable it to flow to the well bore.

Clearwater Formation outcrop, northeast of Fort McMurray
Clearwater Formation outcrop, northeast of Fort McMurray

Athabasca Oil Sands Caprock Characterization

The OSCRIP team conducted a detailed geological characterization of the units above and below the bitumen deposits in the Athabasca Oil Sands Area north of Fort McMurray—more specifically from Township 87 to 99, Range 1 to 13, West of the 4th Meridian (Figure 1).The geologists mapped and characterized selected units from the Precambrian to the base of the Quaternary. The geological mapping focused on the Cretaceous strata above the bitumen and concentrated on the spatial extent and thickness of those units. In addition, the project team realized the nature of the underlying Devonian strata was also very important and could affect reservoir containment. Therefore, those units were also mapped and characterized.

The following publications have been released from this project to date:

Haug, K., Greene, P., Mei, S. and Schneider, C. (2012): Overview of the Oil Sands Caprock Integrity Project; Canadian Rock Mechanics Association Conference, Edmonton, Alberta, Canada, May 7–9, 2012.

Haug, K., Greene, P., Mei, S. and Schneider, C. (2013): Geological and geomechanical characterization of in situ oil sands caprock in the Athabasca Oil Sands Area, Alberta, Canada; American Rock Mechanics Association symposium, San Francisco, California, United States, June 24–26, 2013.

Haug, K., Greene, P., Mei, S. and Schneider, C. (in press): AER/AGS Open File Report.

Schneider, C.L. (2011): Effects of Prairie Formation salt dissolution on the overlying Waterways Formation in northeastern Alberta; Canadian Society of Petroleum Geology Annual Convention, Calgary, Alberta, Canada, May 9-11, 2011 [October 2013].

Schneider, C.L. and Grobe, M. (2013): Regional cross-sections of Devonian stratigraphy in northeastern Alberta (NTS74D, E); AER/AGS Open File Report 2013-05, [October 2013].

Schneider, C.L., Mei, S., Grobe, M. and Haug, K. (2012): Beneath the oil sands: stratigraphy and structural features of the Devonian of northeast Alberta; Canadian Society of Petroleum Geology Annual Convention Calgary, Alberta, Canada, May 14-16, 2012 [October 2013].

Project Lead: Kristine Haug