TY - JOUR
T1 - Present-day stress analysis of the St. Lawrence Lowlands sedimentary basin (Canada) and implications for caprock integrity during CO 2 injection operations
AU - Konstantinovskaya, E.
AU - Malo, M.
AU - Castillo, D. A.
N1 - Funding Information:
The present study is supported by the Ministère du Développement Durable, de l'Environnement et des Parcs du Québec . We are grateful to the Reservoir Development Services group within Baker Hughes Inc. for supporting this stress analysis. We would like to thank Fabrizio Storti, Jonny Rutqvist and anonymous reviewer for detailed comments that helped to improve significantly the manuscript. Special thanks are due to F. Brunner, L. Dean, R. Mireault and FEKETE Associates Inc. (Calgary) for the pore pressure evaluations from DST analyses; O. Heidbach, N. Pinet and R. Lefebvre for technical advices, discussions and review of the original manuscript; L. Massé (JUNEX) for discussions on pore pressure in Becancour area; J. Riva for the correcting of English in the original manuscript; M. Rheault and G. Matton for providing the regional lineament map, R. Thériault for providing the regional digital maps; B. St-Pierre for helping with caliper data integration; and Y. Duchaine for collecting caliper data. Seismic Micro-Technology kindly provided the seismic interpretation software used in this study.
PY - 2012/1/20
Y1 - 2012/1/20
N2 - A geomechanical analysis of the St. Lawrence Lowlands sedimentary basin is important to reliably estimate the maximum sustainable fluid pressures for CO 2 injection that will not reactivate pre-existing faults in the caprock thereby inducing a breeched CO 2 reservoir. This requires the determination of prevailing stresses (orientations and magnitudes), fault and fractures geometries and rock strengths. The average maximum horizontal stress orientation (S Hmax) is estimated N59°E±20° in the St. Lawrence Lowlands. The stress orientations were obtained from stress-induced wellbore breakouts inferred from four-arm dipmeter caliper data in 17 wells. These wellbore failure features are confined to Paleozoic lithological units of the St. Lawrence Platform succession and frontal thrusts of the Quebec Appalachians at depths from 250m to 4km. Our results are consistent with the regional NE-SW S Hmax stress orientation trend that is generally observed in eastern Canada and the U.S. The stresses/pressure gradients estimated for the St. Lawrence Lowlands (depths<4km) are: S hmin 20.5±3kPa/m, S v 25.6kPa/m, S Hmax 40±7.5kPa/m, pore pressure P p 9.8kPa/m indicating a strike-slip stress regime S hmin<S v<S Hmax. The high-angle NE-SW regional faults and fractures in the Paleozoic sedimentary succession and the Grenvillian basement are oblique to the S Hmax stress orientations (10° to 36°) and could be reactivated (slip tendency 0.34 to 0.58) under the present-day stress field if fluid pressures exceeded the critical threshold. Further refinement of regional geomechanical model is required to estimate the maximum sustainable injection pressure necessary for shear reactivation along the regional faults. The regional pore pressure-stress coupling ratio under assumed parameters is about 0.5-0.65 and may contribute to reduce the risk of shear reactivation of faults and fractures. The maximum sustainable P p that would not cause opening of vertical tensile fractures during CO 2 operations is about 18.5-20MPa for the depth of 1km.
AB - A geomechanical analysis of the St. Lawrence Lowlands sedimentary basin is important to reliably estimate the maximum sustainable fluid pressures for CO 2 injection that will not reactivate pre-existing faults in the caprock thereby inducing a breeched CO 2 reservoir. This requires the determination of prevailing stresses (orientations and magnitudes), fault and fractures geometries and rock strengths. The average maximum horizontal stress orientation (S Hmax) is estimated N59°E±20° in the St. Lawrence Lowlands. The stress orientations were obtained from stress-induced wellbore breakouts inferred from four-arm dipmeter caliper data in 17 wells. These wellbore failure features are confined to Paleozoic lithological units of the St. Lawrence Platform succession and frontal thrusts of the Quebec Appalachians at depths from 250m to 4km. Our results are consistent with the regional NE-SW S Hmax stress orientation trend that is generally observed in eastern Canada and the U.S. The stresses/pressure gradients estimated for the St. Lawrence Lowlands (depths<4km) are: S hmin 20.5±3kPa/m, S v 25.6kPa/m, S Hmax 40±7.5kPa/m, pore pressure P p 9.8kPa/m indicating a strike-slip stress regime S hmin<S v<S Hmax. The high-angle NE-SW regional faults and fractures in the Paleozoic sedimentary succession and the Grenvillian basement are oblique to the S Hmax stress orientations (10° to 36°) and could be reactivated (slip tendency 0.34 to 0.58) under the present-day stress field if fluid pressures exceeded the critical threshold. Further refinement of regional geomechanical model is required to estimate the maximum sustainable injection pressure necessary for shear reactivation along the regional faults. The regional pore pressure-stress coupling ratio under assumed parameters is about 0.5-0.65 and may contribute to reduce the risk of shear reactivation of faults and fractures. The maximum sustainable P p that would not cause opening of vertical tensile fractures during CO 2 operations is about 18.5-20MPa for the depth of 1km.
KW - Rock strength
KW - Slip tendency of fault and fracture
KW - St. lawrence lowlands
KW - Stress orientation and magnitude
KW - Stress regime
UR - http://www.scopus.com/inward/record.url?scp=84855825266&partnerID=8YFLogxK
U2 - 10.1016/j.tecto.2011.11.022
DO - 10.1016/j.tecto.2011.11.022
M3 - Article
AN - SCOPUS:84855825266
SN - 0040-1951
VL - 518-521
SP - 119
EP - 137
JO - Tectonophysics
JF - Tectonophysics
ER -