DRILLING & COMPLETION
BOP technology advanced
Post-Macondo safety requirements
drive engineering and technical reforms
The offshore sector, following the 2010 Macondo blowout, is under a techni- cal and engineering reform that aims to enhance BOPs based on lessons learned. The goal is to better control
and shut in wells during all phases of drilling and workover operations by further analyzing standards, methods, equipment, and
techniques linked to BOPs.
Capping stack technology, which was
instrumental in shutting in Macondo, continues to emerge as part of this reform, as
an additional layer of protection for drilling
and workover activities. A notable feature of
capping stacks is the fact that their design
and build synthesizes drilling and workover
and production-based technologies. 1 This,
in turn, raises the following questions: Can
BOPs themselves beneft from being infused with production-based methods and
technologies? And if so, what are the potential benefts for future drilling and workover
operations? The following aims to answer
these questions by examining BOPs from a
production standpoint, with an emphasis on
christmas tree technology.
Comparatively, the functionality and vitality of both BOPs and trees depends on the
provision of a topsides-to-subsea conduit
to bridge power and communication. However, the manner by which each system es-tablishes a path of continuity is unique. For
instance, a BOP’s blue and yellow points of
distribution (PODs), focal points for power
and communication, use a MUX (multiplex)
reel to operate.
Connecting a POD and MUX is achieved
by mating, by hand, a two-part, dry-mateable
MUX connector, whereas a subsea tree’s connection can be mated and unmated subsea.
Because dry-mateable connectors can only
be mated on a rig foor, interfacing with a
BOP stack, whose connector is inoperable at
depth, is not possible. Attempting to remove a
MUX connector, when a fault is linked to it, is
detrimental, because the connector is not designed to be handled by an ROV – reinstalled
in a submerged setting – or to be exposed to
seawater during an unmating sequence. Thus,
engaging it can only be done by tripping the
BOP to surface, in order to replace or repair
the connector. In a situation where time is critical, the time-intensive task of tripping a BOP to
surface is a potential issue.
Conversely, a subsea control module (SCM)
on a tree, which is comparable to a BOP’s
POD, does not use dry mate connectors.
Instead, a topsides-to-subsea conduit is es-
tablished by way of electrical and fber-optic
wet mate connectors that terminate to fy-
ing leads. In a typical subsea distribution
method, a communication path is bridged to
a production asset by jumping out from an
umbilical termination assembly (UTA) via
fying leads to tree. A key feature of these
connectors and fying leads is their ability
to be connected and disconnected multiple
times, at depth, without damaging the fying
lead or connector on either end. Applying
such technology, or a parallel alternative,
(Left) Blue and yellow MUX reels. (Right) MUX connector installed on POD.
ROV-operable connector and flying lead.