Subsea Tail Pipe Installation to Prevent Washout During Drilling
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Solution Overview
Problem
Subsea template systems face issues such as washout, well growth, and loss of cement and drill cuttings during drilling, which are exacerbated by high pressures and challenging operating conditions, requiring a solution that ensures structural integrity, resistance to fatigue, and compliance with industry regulations while minimizing environmental impact.
Innovation Solution
A method involving a subsea template system with a cylindrical tail pipe featuring a serrated end structure and an interface for rotation and axial movement, allowing it to be installed on the seabed and used for drilling an opening for an outer conductor casing, followed by cementing to secure the casing in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a guide pipe is drilled down into the seabed to guide a drilling tool, then the subsea template system can support drilling operations, but the guide pipe must be removed after drilling which creates operational complexity and potential failure points
Solution Approach 1:
The patent extracts the guiding function from a removable guide pipe and integrates it into the permanent subsea template structure. The template structure itself serves as the guide, eliminating the need for separate guide pipes that would need to be installed and removed, thereby reducing operational complexity while maintaining drilling support functionality
2Productivity
If drilling operations are performed without a tail pipe, then the drilling process can proceed, but washout occurs and soil falls into the drill hole compromising well integrity
Solution Approach 1:
The tail pipe is installed into the seabed before drilling operations commence. This preliminary action creates a protective structure that prevents washout and soil collapse during subsequent drilling, ensuring well integrity from the outset while allowing efficient drilling operations to proceed
Solution Approach 2:
The tail pipe acts as a protective cushion or barrier installed beforehand to prevent harmful effects (washout and soil collapse) during drilling operations. This pre-installed protective structure absorbs and mitigates the adverse effects that would otherwise compromise well integrity
3Productivity
If flushing pipes are used during drilling, then drilling operations can proceed, but the flushing pipes cause washout which enlarges the well undesirably
Solution Approach 1:
The tail pipe serves as an intermediary structure between the drilling operations and the seabed soil. It allows drilling fluids to be flushed through the drill string while preventing the harmful effect of washout by providing structural support to the wellbore, thus enabling continuous drilling operations without undesirable well enlargement
4Reliability
If cement is applied to secure the conductor casing in place, then the casing is fixed securely, but cement and drill cuttings are lost to the environment
Solution Approach 1:
The conductor casing is nested inside the tail pipe structure. This nested arrangement contains the cement and drill cuttings within the tail pipe during the cementing operation, preventing environmental release while ensuring secure fixation of the casing. The tail pipe acts as a containment structure for the cementing process
5Adaptability or versatility
If the subsea template system operates at several thousand meters depth, then access to deep seabed resources is achieved, but high pressures and water current create challenging operating conditions
Solution Approach 1:
The subsea template system is designed with parameters (structural strength, material properties, foundation configuration) specifically optimized for deep sea conditions. The system adapts to high pressure and water current by incorporating robust structural design and appropriate material selection that maintain integrity under extreme environmental parameters
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 solution provides a robust and reliable subsea template system that maintains structural integrity, reduces washout and well growth, and minimizes environmental contamination by cement and drill cuttings, while adhering to industry standards and operating conditions.
Implementation Method 1
The tail pipe is cylindrical and comprises a serrated end structure at a first end of the tail pipe
Implementation Method 2
rotating and moving axially the tail pipe relative to the guide and into the seabed
Data Source
AI summary
A method for providing a subsea template system with a tail pipe, and a subsea template system are disclosed. The subsea template system comprising a structure including a guide with an opening, and including a plurality of supports for engaging a seabed; a tail pipe being cylindrical and comprising a serrated end structure at a first (lower) end of the tail pipe, the tail pipe arranged at the opening, and the tail pipe comprising an interface for rotating and axially move the tail pipe relative to the structure. The method comprising: placing the structure and the tail pipe on the seabed; rotating and moving axially the tail pipe relative to the guide and into the seabed; drilling with the drill string an opening for an outer conductor casing; and installing the outer conductor casing and applying cement between the outer conductor casing and the tail pipe.