Fluid flow in the Keathley Canyon 151 Mini-Basin, northern Gulf of Mexico

Abstract

Laboratory experiments and drilling observations are used to estimate vertically upward fluid flow rates of approximately 4 mm/yr in Keathley Canyon, northern Gulf of Mexico. Based on uncertainty in pressure and permeability models, flow rates exceed 1.3 mm/yr but are less than 28 mm/yr. Consolidation experiments document that permeability decreases from 10 −15 m 2 at the seafloor to 10 −18 m 2 at 300 m below seafloor. I use these experimental data with logging-while-drilling data to constrain a permeability function for the basin. Sediment discharge from an open borehole filled with weighted mud is used to estimate a minimum overpressure gradient of 4.3 kPa m −1 in the Keathley Canyon mini-basin. The overpressure gradient and permeability model are input into Darcy's law to estimate an average flow rate for the basin. These flow rates are consistent with estimates of compaction-driven flow from existing regional-scale models of flow in the northern Gulf of Mexico. Hydrate stability calculations for the basin predict a 25 m deepening of the base of hydrate stability due to overpressure.