Subsea Well Cellar Excavation with Modular Liner
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Solution Overview
Problem
Existing methods for placing well pressure control equipment below the water bottom do not effectively resist sediment caving, leading to costly and inefficient operations requiring mobile offshore drilling units.
Innovation Solution
A method involving an excavating apparatus with articulated arms, a drill bit, and motors for controlled movement and rotation, which creates a well cellar by lining it with a cellar liner and excavating a pilot well, allowing for the placement of a wellhead support pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If well pressure control equipment is placed directly on the water bottom, then installation is simple, but sediment caving occurs around the equipment
Solution Approach 1:
The patent applies preliminary action by excavating a cellar structure in the water bottom sediment before placing the well pressure control equipment. This pre-prepared excavation provides a stable, caved-free environment for equipment installation, eliminating the sediment caving problem that would occur with direct placement while maintaining installation simplicity through the modular cellar design.
2Stability of the object's composition
If a cellar is excavated to prevent sediment caving, then equipment stability is improved, but excavation complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the excavation system into modular components: a cellar structure with lateral walls and a floor, and a separate wellhead support structure. This segmentation allows each component to be independently fabricated and installed, reducing overall excavation complexity while providing the stability needed to prevent sediment caving around the equipment.
3Ease of operation
If traditional excavation methods are used, then equipment can be installed, but mobile offshore drilling units are required increasing cost
Solution Approach 1:
The patent introduces an intermediary element - a remotely operated vehicle (ROV) - to perform the excavation and installation operations. This intermediary allows the complex cellar excavation and equipment installation to be performed without requiring expensive mobile offshore drilling units, thereby reducing operational costs while maintaining the ability to install equipment stably in the water bottom.
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
Enables efficient excavation and placement of well pressure control equipment without sediment caving, reducing costs and operational inefficiencies by stabilizing the wellhead and pressure control equipment below the water bottom.
Implementation Method 1
A method is provided for excavating a well cellar with a motorized drill bit
Implementation Method 2
lowering the cellar liner into the well cellar until a top of the cellar liner is substantially level with the bottom of the body of water
Data Source
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AI summary
A method for excavating a well cellar includes lowering an excavating apparatus having a cellar liner therein to a bottom of a body of water. The well cellar is excavated while contemporaneously lowering the cellar liner into the well cellar until a top of the cellar liner is substantially level with the bottom of the body of water. A pilot well is excavated below a bottom of the cellar. A well head support pipe is inserted into the pilot well. The bottom of the well cellar and a top of the cellar liner are covered.