Predrill pore-pressure prediction and pore pressure and fluid loss monitoring during drilling: A case study for a deepwater subsalt Gulf of Mexico well and discussion on fracture gradient, fluid losses, and wellbore breathing

Abstract

In this case study, the overburden, pore-pressure, and fracture gradients are calculated for several nearby analog wells and subsequently used to generate a predrill pore-pressure prediction for the deepwater subsalt Gulf of Mexico well, Flying Dutchman, located in Green Canyon 511 no. 1 (OCS-G 22971). Two key analog wells penetrated the lower Miocene and have sufficient data to generate pore-pressure profiles. Subsequently, the predrill pore-pressure prediction is found to be in good agreement with the pore pressure estimated from well logs while drilling. During the drilling phase of the Flying Dutchman well, two zones of significant fluid loss and wellbore breathing were encountered and are evaluated as a means of determining the formation types where they are most likely to occur, as well as their related minimum horizontal stress and fracture gradient.