Qualitative Risk Analysis of Emergency BOP Control Systems to Ensure Availability

Abstract

fax 01-972-952-9435. AbstractMany of the latest generation of ultra deepwater capable rigs included emergency BOP (Blow Out Preventer) control capabilities, sometimes referred to as secondary intervention systems. Such systems represent the last line of defense in containing a well. Should it be necessary and unavailable, the result could be environmentally and humanly catastrophic.Building on installations that have been in service for many years, these capabilities range in functionality and purpose, from providing an alternate means to operate BOP functions in the event of total loss of the primary control system to assisting personnel during incidents of imminent equipment failure or well control problems. They can be actuated automatically or manually, and utilize components of the primary BOP control system or be totally independent. With as many permutations as there were rigs built, an understanding of the capabilities and limitations that exist on a particular rig is of critical importance in assessing the risks associated with a drilling program.While there currently are no standard terms in use to describe the essential attributes of systems, this paper recommends definitions and terms for a common understanding. The defined terminology is then utilized to compare and contrast system parameters, identifying various system strengths and weaknesses for use in risk analyses.Possible enhancements to existing emergency control systems will then be discussed, as well as their benefits and anticipated costs. Finally, the paper will recommend best practices for moored rig operations and those for operations utilizing DP (Dynamic Positioning).

Integrated risk management: a Petrobras application in offshore well construction safety to minimize critical emergency disconnections

“…The ultimate consequence could be a blowout and/or severe damage to subsea production systems like production templates, resulting in risk to personnel, environmental damage, financial loss and harm to the reputation of the company (Paula and Fonseca 2013). Currently, all dynamically positioned rigs are equipped with an emergency disconnect button which initiates a pre-programmed sequence of functions designed to secure the well in a minimal amount of time prior to disconnecting the LMRP riser connector (Sattler and Lewis 2004). An emergency disconnect sequence (EDS) is a sequence of actions, events and interlocks that are automatically initiated once the EDS button is pressed on any BOP panel in the rig.…”

“…It is interesting to note that some functions are activated even though they should already be in a particular position. This is done to ensure the well is secured upon disconnecting (Sattler and Lewis 2004). Despite extensive technology, an emergency disconnection may occur at any time in dynamically positioned drilling rigs, sometimes surprisingly so, be it through human error, adverse environmental conditions or blackouts.…”