Translate 
Abstract
ABSTRACT Chalk failure in six production wells without gravel pack in the Valhall field are observed to occur in two main periods, the early and the late. Early-period failures are related to pre-existing natural damage of the formation and wellbore operations such as drilling and well completion/perforation. Late-period failures are related to depletion in reservoir pressure. As pore pressure falls the effective stress on the formation chalk increases until its yield stress is reached. Early and late-period failures are both triggered by stresses related to pressure gradients in the formation near a wellbore. Shut-in and re-opening of production wells, for example, give rise to high pressure gradients that cause chalk failure. Fluid production below the bubble point also triggers chalk failure. The analyses of 19 chalk failure incidents are expressed in a conceptual damage-release model.
Published Version
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
