RCD Misalignment Correction via Spherical Shoulder and Socket

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Solution Overview

Problem

Misalignment of the drill string with the wellbore poses a persistent challenge for rotating control devices (RCDs), leading to sealing element failures and potential damage to bearing assemblies, particularly in dynamic drilling rig environments where constant alignment is difficult to maintain.

Innovation Solution

The implementation of a misalignment correction device within RCDs, featuring a spherical shoulder and matching socket profiles, along with anti-rotational devices such as keys and slots, allows for rotational and angular compensation, preventing unintentional rotation and enhancing the robustness of the connection between the RCD and the drill string, thereby reducing friction and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If rig adjustments are made to maintain alignment, then alignment precision is improved, but operational complexity increases and requires continuous personnel intervention

Engineering Contradiction:
Improvealignment precisionVSAvoidoperational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The RCD incorporates self-aligning features including spherical interfaces and floating mounting capabilities that automatically compensate for misalignment between the drill string and wellbore. The system uses spherical shoulders and socket profiles that passively adjust to maintain proper alignment without requiring external intervention or complex adjustment mechanisms.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If passive misalignment correction techniques are implemented, then operational simplicity is improved, but alignment correction effectiveness may be limited

Engineering Contradiction:
Improveoperational simplicityVSAvoidalignment correction effectiveness
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention employs spherical shoulders and socket profiles throughout the RCD assembly. These spherical interfaces provide multi-degree-of-freedom alignment compensation, allowing the system to passively adapt to misalignment conditions while maintaining effective sealing and mechanical connection. The spherical geometry enables correction of both angular and lateral misalignment.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The RCD incorporates multiple nested alignment correction features, including spherical interfaces within bearing assemblies, floating mounting capabilities within the RCD body, and adjustable seal positions. These nested features work together in layers to progressively correct misalignment while maintaining operational simplicity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If rig adjustments are made to correct misalignment, then sealing element reliability is improved, but time consumption increases

Engineering Contradiction:
Improvesealing element reliabilityVSAvoidtime consumption
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The RCD is pre-configured with self-aligning features and floating mounting capabilities that automatically compensate for misalignment before sealing elements are engaged. This preliminary alignment compensation prevents misalignment-induced sealing failures without requiring time-consuming adjustments during operation.

Inventive Principle:
Principle #10Preliminary action

4Strength

If the RCD structure is made more robust to prevent damage, then device strength is improved, but the device complexity increases

Engineering Contradiction:
Improvedevice strengthVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The RCD incorporates dynamic alignment compensation features including floating mounting capabilities and spherical interfaces that allow the structure to adapt to misalignment conditions. These dynamic features protect bearing assemblies and other components from damage caused by rigid misalignment without requiring complex protective structures.

Inventive Principle:
Principle #15Dynamics

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 solution effectively extends the lifespan of sealing elements, prevents damage to bearing assemblies, and ensures reliable operation by accommodating misalignment, even in fluctuating drilling rig conditions without the need for continuous personnel intervention.

Implementation Method 1

a spherical shoulder and matching socket profiles

Methodology Applied
Scientific EffectSpherical geometry alignment: Geometry

Implementation Method 2

anti-rotational devices such as keys and slots, prevents unintentional rotation

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Fastener

Implementation Method 3

reducing friction and wear

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP3805519B1Misalignment mitigation in a rotating control device
Publication Date: 2024.01.24 WEATHERFORD TECHNOLOGY HOLDINGS LLC
  • EP3805519B1 patent drawingFigure 1A
  • EP3805519B1 patent drawingFigure 1B
  • EP3805519B1 patent drawingFigure 1C

AI summary

An apparatus for the correction of misalignment of a piece of oilfield equipment within a rotating control device (RCD) 10, comprise a misalignment correction device, wherein part of the piece of oilfield equipment is located within the misalignment correction device. A spherical shoulder is on a first surface of a misalignment correction device, and a socket is defined on a second surface of the misalignment correction device. The socket is configured to engage the spherical shoulder. The apparatus further includes a sealing element (140) having an internal diameter (144) and an external diameter (146), wherein the internal diameter (144) is configured to seal against the piece of oilfield equipment (40). The apparatus also includes a pressure reduction system (120), which comprises a piston assembly (129) configured to reduce a wellbore pressure (P2) to a reduced pressure experienced by the external diameter (146) of the sealing element (140).