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Artificial intelligence-assisted station keeping for improved drillship operations
dynamics of drillships becomes particularly chal- Although conventional DPS systems offer de-
lenging under the combined effects of environ- pendable performance, their “black-box” design
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mental forces and operational loads. A notable limits transparency and adaptability. The use of
issue is the undesirable coupling between heave advanced solutions, such as artificial intelligence
and pitch motions, which results in additional (AI)-based systems, helps enhance safety, oper-
bending moments on the hull and necessitates ational efficiency, and real-time decision-making
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careful consideration during the vessel’s design. onboard. By reducing operational downtime and
Moonpools, vertical apertures extending through improving local control, these innovations address
the deck and hull, play a crucial role in drillship the limitations of conventional DPS and pave the
functionality. Moonpools can lead to increased way for more reliable and efficient station-keeping
natural frequencies in the longitudinal sloshing systems.
mode when the vessel’s draft and width are si- Current response control methods for offshore
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multaneously reduced. Drillships are equipped vessels focus on maintaining position and stabil-
with advanced technology for real-time monitor- ity under challenging environmental conditions.
ing and data collection, enhancing safety and One of the most widely used approaches is the
decision-making processes during operations. Be- DPS, which utilizes thrusters and propellers for
yond their primary role in drilling, they are also automated control. Model-based control tech-
deployed to conduct geological surveys and sup- niques have facilitated smooth transitions be-
port subsea operations. This multifaceted func- tween station-keeping and position tracking, im-
tionality, combined with their mobility, opera- proving operational efficiency. Various iterations
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tional efficiency, and cutting-edge capabilities, es-
of DPS controllers, including PID (proportional,
tablishes drillships as indispensable assets in the
integral, and derivative) control, output feedback
offshore oil and gas industry. Drillships are cate-
control, nonlinear control, and hybrid methods,
gorized into three types based on their function- 7
have further enhanced system reliability. Addi-
ality and storage capacity, each tailored to meet
tionally, DPS systems feature redundancy that is
specific operational requirements:
categorized into three classes, with higher-class
systems offering increased reliability and safety
(i) Drillships without oil storage are dedi-
through redundant components.
cated exclusively to exploratory drilling.
(ii) Drillships with limited oil storage are de- Alongside these developments, adaptive fuzzy
signed for exploratory drilling operations. control strategies have been incorporated into
(iii) Drillships equipped with extensive oil DPS, enabling more precise vessel positioning and
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storage capabilities alongside exploratory heading control, even in complex sea conditions.
drilling functions. Furthermore, advanced detection technologies
like the single shot multibox detector have im-
proved both static and dynamic data collection
These classifications enable drillships to effi-
on obstructions, thereby enhancing navigation
ciently extract oil and gas from offshore reserves
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through augmented reality displays. These inno-
while addressing diverse operational demands and
vations continuously improve offshore vessel re-
ensuring optimal performance across exploration
sponse control, making the systems more adap-
and production scenarios.
tive, reliable, and efficient in challenging maritime
Drillships rely on dynamic positioning sys- environments.
tems (DPS) or mooring systems to maintain their
position during drilling and production activities. Several specialized response control systems
DPS is an active station-keeping system that uses have been proposed to optimize drillship perfor-
thrusters and propellers to counteract environ- mance in challenging environments. For instance,
mental forces, ensuring stability and precise posi- a heave compensation system was introduced for
tioning even in challenging sea conditions. Con- deepwater operations under irregular wave condi-
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versely, mooring systems use anchor lines for pas- tions, effective within certain linearity bounds.
sive restraint. While DPS provides superior sta- Additionally, the impact of various physical com-
bility crucial for successful drilling operations, ex- ponents on the multibody dynamics of offshore
structures was explored, 11 which provided valu-
treme environmental loads can induce excessive
able insights into refining control strategies for
roll and pitch motions, leading to significant stress
complex environmental scenarios.
concentrations, particularly around the moonpool
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region. These dynamic loads can make drillships A novel control system for autonomous
moderately unstable, highlighting the importance surface vessels, incorporating external distur-
of robust station-keeping mechanisms. bances using the backstepping technique, was
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