Slip Joint Sealing Assembly for Riser Pressure Retention

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Solution Overview

Problem

Conventional slip joints in drilling systems are not designed to retain significant pressure in the riser annulus, which is a limitation for advanced drilling methods like managed pressure drilling or mud cap drilling that require pressurization.

Innovation Solution

A high-pressure slip joint configuration featuring a tubular inner and outer barrel with a sealing assembly that includes a movable actuator and seal, utilizing an annular packing element to create a fluid-tight seal between the barrels, allowing for pressurization and movement while maintaining pressure containment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If conventional slip joints are used, then the rig can move with sea level changes, but the riser annulus cannot retain significant pressure

Engineering Contradiction:

Improvefluid pressure retentionVSAvoidseal effectiveness

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

The sealing assembly is divided into multiple independent seals (first seal and second seal) that can be actuated separately. This segmentation allows progressive sealing - the first seal provides initial sealing, and the second seal provides backup sealing, thereby improving reliability while maintaining pressure retention capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system incorporates a backup seal that is activated only when the primary seal becomes compromised. This beforehand cushioning approach ensures that pressure retention is maintained even if the first seal fails, improving reliability without sacrificing pressure retention capability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Stress or pressure

If multiple sealing assemblies are added to improve pressure retention, then fluid pressure can be contained, but device complexity increases

Engineering Contradiction:

Improvefluid pressure retentionVSAvoidsealing assembly complexity

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

Both seals are actuated by the same piston through the same hydraulic fluid pressure mechanism. This multi-functionality approach allows a single actuation system to control multiple seals, reducing overall system complexity while maintaining the ability to retain fluid pressure

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The piston and hydraulic fluid system are merged to simultaneously actuate both seals. By combining the actuation mechanism for both seals into a single integrated system, the patent reduces device complexity while achieving reliable pressure retention through multiple seals

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the seal is pushed into engagement with the sealing surface, then fluid tight seal is achieved, but wear and frictional heating increase

Engineering Contradiction:

Improveseal effectivenessVSAvoidwear and frictional heating

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The first seal engages with the sealing surface beforehand to provide the primary fluid-tight seal. This prior engagement reduces the burden on the second seal, allowing it to engage more gently and reduce wear and frictional heating while maintaining seal effectiveness

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The sealing function is segmented into two separate seals that engage sequentially. This segmentation distributes the sealing load and reduces the frictional heating and wear on any single seal, while maintaining overall seal effectiveness through the combined action of both seals

Inventive Principle:

Principle #1Segmentation

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 effectively retains fluid pressure within the riser annulus, enabling the use of advanced drilling methods by providing a reliable, leak-proof seal that adapts to changing pressures and movements, reducing wear and friction through the use of specialized materials and design features.

Implementation Method 1

the piston being movable in response to fluid pressure in the chamber, to push the seal into engagement with one of the sealing surfaces

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

the piston in use engaging with the annular packing element so that movement of the actuator to push the seal into engagement with one of the sealing surfaces causes the annular packing element to constrict around the seal

Methodology Applied

Scientific EffectRadial constriction: Compression

Data Source

PatentUS9506300B2Slip joint and method of operating a slip joint

Publication Date: 2016.11.29 GRANT PRIDECO LP

AI summary

A slip joint (10) having a tubular inner barrel (11b) and a tubular outer barrel (11a), the inner barrel (11b) lying at least partially within the outer barrel (11a), the slip joint further comprising a sealing assembly (12a), (12b), (12c) which is operable to provide a substantially fluid tight seal between two sealing surfaces comprising an interior surface of the outer barrel 11a and an exterior surface of the inner barrel (11b), the sealing assembly (12a), (12b), (12c) including an actuator (20) and a seal (46), the actuator (20) being movable to push the seal (46) into engagement with one of the sealing surfaces.