Flush Tool Joint Drill String for RCD Sealing
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Solution Overview
Problem
Conventional rotating control devices in Managed Pressure Drilling (MPD) systems experience wear and require frequent replacement, leading to rig downtime and safety concerns due to the continuous movement of drill strings through sealing elements.
Innovation Solution
A drill pipe apparatus with a rotating sealing device and drill string sections where the second drill string section has tool joints flush with the tubular body, reducing wear on sealing elements by maintaining a consistent outer diameter and allowing the drill string to pass through the RCD without damaging the sealing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drill strings with protruding tool joints are used, then the drill string provides sufficient strength and flexibility for deviated and horizontal wells, but the sealing elements experience continuous wear and require frequent replacement
Solution Approach 1:
The drill string is divided into two distinct sections: a first section with conventional protruding tool joints for strength and flexibility, and a second section with flush tool joints for sealing compatibility. This segmentation allows each section to fulfill its specific function without compromising the other.
Solution Approach 2:
Different parts of the drill string are given different geometric properties: the first drill string section has tool joints that protrude for structural strength, while the second drill string section has tool joints that are flush with the tubular body for sealing surface compatibility. This local differentiation resolves the contradiction between strength requirements and sealing requirements.
2Productivity
If drill strings with protruding tool joints move through the rotating control device, then drilling operations can proceed, but wear of sealing surfaces occurs leading to safety issues
Solution Approach 1:
The drill string is segmented into a first section for structural functions and a second section specifically designed for RCD passage. The second section's flush tool joints eliminate protrusions that cause sealing element wear, allowing continuous drilling operations without compromising sealing integrity.
Solution Approach 2:
The second drill string section has a localized geometric modification where tool joints are flush with the tubular body, creating a smooth sealing surface that prevents wear on RCD sealing elements while maintaining the overall drilling operation continuity.
3Strength
If the outer diameter of tool joints is larger than the tubular body, then connection strength is improved, but the sealing surface consistency is compromised
Solution Approach 1:
The drill string is divided into two sections with different geometric characteristics. The first section maintains conventional larger-diameter tool joints for connection strength, while the second section uses flush tool joints for outer diameter consistency, allowing both strength and sealing requirements to be met in different locations.
Solution Approach 2:
Different sections of the drill string have different local geometric properties: the first section has enlarged tool joints for strength where needed, while the second section has uniform outer diameter for sealing surface consistency where it contacts the RCD.
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 extends the lifespan of sealing elements, maintains a robust seal, and reduces rig downtime by minimizing wear and friction during drilling operations, especially in deviated and horizontal wells.
Implementation Method 1
the rotating sealing device is configured to form a fluid seal against an outer surface of the second drill string section
Implementation Method 2
maintaining a consistent outer diameter and allowing the drill string to pass through the RCD without damaging the sealing elements
Data Source
AI summary
The invention provides a managed pressure drilling system. The system comprises a rotating sealing device and a drill string assembly comprising a plurality of drill pipe members. Each drill pipe member has a first tool joint having a first tool joint outer diameter; a second tool joint having a second tool joint outer diameter; and a tubular body between the first and second tool joints having a tubular body outer diameter. In at least one section of the drill string the first tool joint outer diameter, the second tool joint outer diameter and the tubular body outer diameter are substantially the same. The rotating sealing device is configured to form a fluid seal against at least a part of the at least one section of drill string.