Offshore Drilling Heave Compensation Synchronization
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Solution Overview
Problem
Offshore drilling systems face challenges in maintaining effective wellbore pressure control and efficient drilling operations due to heave motion caused by waves, which can impair the synchronization of the working deck and travelling block, leading to reduced drilling efficiency and potential damage to equipment.
Innovation Solution
The implementation of an integrated heave compensation system that includes a mechanical connector between the fixed length section of the riser and the mobile working deck, along with a dynamic positioning system, allows for synchronous heave compensation of the travelling block and working deck, maintaining constant vertical spacing and reducing the impact of heave motion on drilling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the diverter is attached to the mobile working deck, then the telescopic joint can compensate for vessel motions, but the vertical spacing between the working deck and riser becomes variable, impairing heave compensation
Solution Approach 1:
The system separates the diverter from the mobile working deck and attaches it to the fixed hull instead. This segmentation allows the working deck to maintain its heave compensation function while the diverter remains stationary relative to the vessel structure, resolving the conflict between motion compensation and vertical spacing control
Solution Approach 2:
The patent introduces an intermediary connection system where the diverter is attached to the hull via a stationary platform, and the riser connection is managed through a separate telescopic joint mechanism. This intermediary arrangement allows independent optimization of both heave compensation and diverter positioning
2Adaptability or versatility
If the inner barrel of the telescopic joint is secured to the diverter via a flexible joint, then angular movement is permitted to compensate for vessel motions, but the telescopic joint can be in any position within a fictious cone, reducing positioning precision
Solution Approach 1:
The system separates the angular movement function (handled by the flexible joint at the diverter) from the positioning function (handled by the telescopic joint length adjustment). This segmentation allows the telescopic joint to maintain precise vertical positioning while the flexible joint provides the necessary angular adaptability
Solution Approach 2:
Instead of allowing the telescopic joint to accommodate angular movements directly, the patent inverts the approach by providing angular adaptability at the diverter end through the flexible joint, thereby protecting the telescopic joint's positioning precision while maintaining overall system adaptability
3Length of moving object
If the telescopic joint extends through the moonpool in elevated positions, then the working deck can reach elevated positions, but this may interfere with drilling operations and equipment access
Solution Approach 1:
The patent extracts the telescopic joint extension function from the working deck elevation mechanism. By allowing the telescopic joint to extend independently through the moonpool while the working deck remains at an optimized operational height, the system achieves both elevated positioning capability and maintained accessibility for drilling operations
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
This configuration enhances drilling efficiency by ensuring accurate and reliable heave compensation, preventing damage to equipment and allowing for continuous operation even in harsh sea conditions, while maintaining accessibility for pipe racking and other operations.
Implementation Method 1
an integrated heave compensation system configured to provide a heave compensation of the travelling block as well as of the mobile working deck
Implementation Method 2
a mechanical connector is tensioned between the fixed length section of the riser or to the outer barrel of the telescopic joint on the one end, e.g. via the tension ring, and the mobile working deck
Implementation Method 3
the inner barrel of the telescopic joint is secured to the diverter via a flexible joint
Data Source
AI summary
The first aspect of the present invention relates to an offshore drilling system and a method for performing subsea wellbore related activities involving a riser extending between the vessel and a subsea wellbore. The offshore drilling system comprising a drilling vessel with a floating hull, a drilling tower and a tubular string main hoisting device. A vertically mobile working deck with a rig floor slip device is positioned above the moonpool. A telescopic joint and a diverter are provided, wherein the inner barrel of the telescopic joint is secured to the diverter via a flexible joint. Furthermore an integrated heave compensation system is provided such that said travelling block and the mobile working deck move synchronously in heave compensation.