APPLICATION OF SEQUENCE STRATIGRAPHY TO EVALUATE AND QUANTIFY THE CAPACITY OF OFFSHORE CO2 STORAGE RESERVOIRS IN THE GEORGES BANK BASIN

We examine the carbon storage potential of the Cretaceous strata in the Georges Bank Basin (GBB), located ~100 km offshore Massachusetts. The basin contains over 10 km of post-rift sediments, including about 5 km of Upper Jurassic to Upper Cretaceous sediments deposited in fluvial, deltaic, and shelf environments that may produce stratigraphic reservoirs that can be utilized to sequester captured supercritical CO₂. We apply a "back to basics" approach to sequence stratigraphy that involves assessing sediment stacking patterns to identify depositional sequences and systems tracts to establish a sequence stratigraphic framework for the Upper Jurassic fluvial and Cretaceous fluvial-deltaic sedimentary sequences within the GBB. Our interpretation of gamma-ray logs from 10 industry wells drilled in the 1970s and 1980s reveals six thick (>100m) depositional sequences within the Upper Jurassic and Cretaceous strata. Applying seismic stratigraphy to a 55,000 km grid of marine multi-channel seismic data collected from 1973 to 1982, we interpret the spatial extent of the well-log sequences across the basin. Isopach maps generated from seismic interpretations suggest the basin was filled from a proximal drainage basin in present-day New Hampshire and southern Maine, with additional contribution from distal sources in Northern Maine and New Brunswick. We identify the Missisauga Formation (Lower Cretaceous) sequences as viable carbon sequestration targets in the GBB, potentially storing 4.2-8.4 Gt of supercritical CO₂. These sequences lie at depths suitable to maintain storage pressure beneath the Naskapi Formation, a widespread shale unit acting as a confining bed. However, heterolithic sands from likely fluvial environments present challenges compared to deltaic sands of the overlying Logan Canyon Formation sequences. We also identify suitable Logan Canyon reservoir targets in the western part of the basin, likely capable of storing 9.7-19.5 Gt of CO₂ sealed below the supercritical storage level. Overall, the GBB is a significant offshore carbon storage target, potentially accommodating ~14-28 Gt of supercritical CO₂ in Lower Cretaceous sandstones that could be critical resources if long-term climate mitigation strategies require gigatons of CO2 to be sequestered globally per annum through the adoption of CCS and BECCS.