Ram BOP Inner Guide Seal Assembly for Wireline Centering

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Solution Overview

Problem

Existing ram-type BOP systems face challenges in maintaining an effective seal during well intervention services, particularly due to pressure spikes and temperature-related grease thinning, which can lead to damage of wireline and increased replacement costs, and prior guide systems are difficult to replace and prone to deformation.

Innovation Solution

An improved inner guide seal assembly with a specially shaped guide body and separate sealing element that centralizes the wireline within the BOP, preventing damage and allowing for easy replacement of the seal assembly or individual elements, reducing the risk of deformation and costly wireline damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a prior guide system is used in ram-type BOP systems, then wireline centering is achieved, but the guide system is difficult to replace and prone to deformation under pressure

Engineering Contradiction:
Improveseal effectivenessVSAvoidguide system replacement
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The guide system is divided into multiple guide blocks that can be independently replaced. Each guide block is a separate component that can be removed and replaced without replacing the entire guide system, making maintenance easier and reducing downtime.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide blocks are extracted as separate replaceable components from the overall guide system. This allows the guide blocks to be removed individually for replacement or inspection without affecting the entire guide system structure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If grease is pumped into the grease injection head at high pressure to maintain seal, then well bore pressure is held back, but grease thinning occurs due to temperature and chemical exposure

Engineering Contradiction:
Improvegrease seal effectivenessVSAvoidgrease viscosity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system monitors and responds to changes in grease properties by adjusting operating parameters. When grease thinning is detected due to temperature or chemical exposure, the system can adjust pumping pressure or frequency to maintain seal effectiveness despite the changed grease characteristics.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If ram bodies close to seal around wireline, then well bore pressure is contained, but wireline damage may occur due to misalignment or excessive force

Engineering Contradiction:
Improvepressure containmentVSAvoidwireline damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Guide blocks serve as intermediary elements between the ram bodies and the wireline. These guide blocks contact the wireline first to provide alignment and guidance, preventing direct contact between the wireline and the ram bodies, thereby eliminating wireline damage while maintaining pressure containment.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If inner seal elements are subjected to excessive squeezing force, then sealing is improved, but the ram body may deform or be damaged

Engineering Contradiction:
Improveseal integrityVSAvoidram body structural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The guide blocks act as intermediary elements that distribute and redirect the squeezing forces. Instead of all sealing forces being applied directly to the ram body, the guide blocks intercept and redirect these forces, reducing the peak loads on the ram body while maintaining effective sealing through the guide blocks themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP1917415A2Inner guide seal assembly for a ram type BOP system
Publication Date: 2008.05.07 NAT OILWELL DHT LP

AI summary

An improved ram inner seal assembly used in ram-type BOPs is disclosed. The disclosed invention provides an inner guide seal assembly that comprises a specially shaped guide body and a separate sealing element. When the ram-type BOP is closed, two opposing rams move toward one another, and the inner guide seal assembly guides a wireline (or other tubular) toward the center of the vertical bore through the BOP. The inner guide seal assembly's proximity to the ram body's centerline axis helps ensure that a positive seal is formed and that no damage occurs to the device in the central bore of the BOP. The separate, specially-shaped sealing element can be easily inserted into and removed from the guide body of the inner guide seal assembly for easy replacement.