Sedimentology of the Upper Cretaceous Basal Foremost and Medicine Hat Formations in Newell County, Alberta: Implications for a Carbon Capture and Sequestration Monitoring Program

Abstract

Description: Proper implementation of carbon capture and storage (CCS) requires the capability of the reservoir rock to store and maintain CO₂ without subsequent release. To address this challenge, Carbon Management Canada has constructed a Field Research Station (FRS) located in Newell County, Alberta on a 2.5 km² site generously provided by Cenovus Energy. The FRS pilot well, Countess 10-22-17-16W4, is a potential injection well drilled to a TVD of 550m. The objectives for the FRS are to: develop and improve monitoring technologies for CO₂ detection at relatively shallow depths as well as map temporal changes in cap rock properties. Prior to CO₂ injection, it is necessary to characterize the target formations. In this study we utilize subsurface geological data and outcrop analysis towards a sedimentological understanding of both conventional (Basal Foremost) and unconventional (Medicine Hat) target formations at the pilot well location. Applications: The information provided by this study is applicable for the sedimentological characterization of present and future CCS projects. In addition, our comparative approach to core data and outcrop analysis allows for a broader perspective on sedimentological processes and the lateral extent of silt and sand bodies within marine shales. Results and Conclusions: Wireline logs, well core, and outcrop analysis were employed to build a sedimentological profile of the Basal Foremost and Medicine Hat Formations. From this data we gained insight into the reservoir qualities (eg. Permeability, porosity, flow orientation) as well as map the lateral extent of these formations. Briefly, the Basal Foremost Formation indicates a marine to non-marine transition in which a mature, well-sorted prograding shoreface sandstone is capped by a backshore coal zone. The Medicine Hat Formation represents a marine environment in which the deposition of coarsening upward sandstone units is followed by finer grained siltstones and mudstones, which conformably transition to the overlying First White Speckled Shale. Although the thickness of the sand units is smaller than the Basal Foremost Formation (cm vs m), the greater lateral extent and abundant bioturbation may suggest the possibility of the Medicine Hat Formation as a viable alternative target for CCS. Technical Contributions: This study provides foundational sedimentologic information for both traditional and novel CCS target formations at a relatively shallow depth.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016