Proactive Well Integrity Management Through the Estimation of Residual Well Life

Abstract

Abstract Among the strategic issues of the Oil & Gas Industry, management of well integrity currently plays a key role, since it allows to simultaneously achieve two major objectives: minimize risk of uncontrolled release of hydrocarbons and extend the life of wells, thus getting the most from reservoirs. Well integrity is about maintaining at least two independent well barriers at all times. This prevents reservoir fluids from being unintentionally and uncontrollably released at surface, and from migrating to other underground layers. However, degradation over time may weaken the elements comprising well barrier envelopes, and therefore impair well integrity if not taken into due consideration. This paper describes an innovative approach to well integrity, which effectively puts the concept of "proactive management" into practice: the aim is not only to ensure that wells operate safely today, but also to be reasonably confident that they will properly work in the future in order to achieve an extended production life and optimize operational expenditures. The subject approach complies with the ISO TS 16530-2 "Well Integrity for the Operational Phase", and uses both a failure mode analysis and a risk assessment technique to estimate the residual well life, on the basis of the expected degradation rate of well barrier elements. The described approach enables to: Evaluate the current well integrity status through a risk-based perspectiveAnticipate future well integrity issuesElaborate a suitable risk reduction action planIdentify proper monitoring and maintenance requirements. A dedicated software has been developed to effectively support the analysis of the current well integrity status and the identification of the well barrier elements that are expected to become critical in the future. The main characteristics of the software are also described.