Bi-conical Offshore Drilling Platform Ice Resistance
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Solution Overview
Problem
Traditional offshore drilling rigs face significant challenges in ice-infested waters due to lack of ice resistance and harsh environmental conditions, leading to operation-hour losses and extended exploration periods in Arctic regions.
Innovation Solution
An offshore floating drilling platform with a bi-conical structure comprising an upper cone, transition section, and lower cone, designed with specific frustum shapes and ballast compartments to enhance ice resistance and motion performance, featuring a variable cross-section center well and chain-cable-chain mooring system for stability and protection from ice loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional semi-submersible drilling rigs and drilling ships are used in Arctic areas, then they can operate in open waters, but they must be removed from the site when ice flows occur, causing operation-hour loss
Solution Approach 1:
The platform employs a bi-conical structure with specific geometric parameters (upper cone with side dip angle ≥30°, lower cone with side dip angle >30°, transition section height <20% of total height) that fundamentally change how the platform interacts with ice loads, enabling continuous operation in ice-infested waters without the need to evacuate during ice flow events
Solution Approach 2:
The platform incorporates a dynamic ballast system with multiple ballast compartments that can adjust the platform's draft and buoyancy distribution in real-time. This allows the platform to adapt its configuration when ice flows are detected, optimizing ice resistance and maintaining operational capability throughout varying ice conditions
2Stability of the object's composition
If existing drilling rigs and production platforms are designed for harsh environment with favorable motion performance, then they achieve good motion response, but they lack ice resistance capability
Solution Approach 1:
The platform structure is segmented into distinct functional zones: upper cone for drilling operations, transition section for structural optimization, lower cone for ballast and stability, and bottom frame for mooring. This segmentation allows each zone to be optimized independently - the upper sections for motion performance and the lower sections for ice resistance
Solution Approach 2:
The platform utilizes composite structural design combining different materials and structural forms (frustum shapes, spherical caps, modular compartments) to achieve both favorable motion performance through optimized hydrodynamic characteristics and ice resistance capability through robust lower structure design with large bottom frame and ballast systems
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The platform effectively reduces ice load, increases stability, and minimizes operation-hour losses by allowing operation in harsh environments, with optimized drafts and ballast systems for enhanced buoyancy and damping, ensuring continuous drilling operations in Arctic conditions.
Implementation Method 1
Through ballast compartments are designed outside the sidewall of the upper cone, the transition section and the lower cone... the ballast compartments are internally connected from top to bottom
Implementation Method 2
the said upper cone is an inverse frustum, and the lower cone is a normal frustum; the transition section is an inverse frustum... the side dip angle of the upper cone is larger than or equal to 30 degrees; the side dip angle of the lower cone is larger than 30 degrees
Implementation Method 3
a mooring cable conduit is arranged within the ballast compartments from top to bottom... a mooring cable is arranged within and along the mooring cable conduit
Data Source
AI summary
An offshore floating platform for operating in ice-infested waters and harsh environment for oil/gas drilling and exploration in Arctic area comprises four (4) sections, i.e., an upper cone, a transition section, a lower cone and a bottom frame. The upper cone, the transition section, the lower cone and the bottom frame are coincident with a centerline, and a through center well is designed around the centerline from top to bottom. The diameter at the bottom frame is smaller than that of the main body of the center well. The upper cone, the transition section and the lower cone are internally connected and divided into plural compartments. Through ballast compartments are designed outside the sidewall of the upper cone, the transition section and the lower cone vertically connected with a consistent cross-sectional area from top to bottom. Plural ballast compartments and void compartments are arranged within the bottom frame.