Subsea Tree Valve Testing Using Local Pressure Differential Control

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Solution Overview

Problem

Conventional methods for testing subsea well valves are hazardous and inefficient due to the need for high-pressure pressurization, which can require large fluid quantities and pose safety risks, especially when the upstream pressure is close to ambient pressure.

Innovation Solution

A method and system for testing subsea well valves by isolating a region adjacent to the valve, using a subsea pressure manipulation device to achieve a target pressure differential below or above ambient pressure, eliminating the need for a topside service line and reducing safety risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If high-pressure pressurization is used to achieve pressure differential for valve testing, then the required pressure differential can be achieved, but safety risks increase and large quantities of fluid are required

Engineering Contradiction:

Improvepressure differentialVSAvoidsafety risks

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

Instead of pressurizing the upstream side to create pressure differential, the patent depressurizes the downstream side below ambient pressure. This inverted approach achieves the same pressure differential effect while avoiding the safety hazards of high-pressure operations and reducing fluid consumption.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the pressure parameter from positive pressurization (above ambient) to negative pressurization (below ambient) on the downstream side. This parameter change allows achieving the required pressure differential across the valve without the harmful effects of high-pressure systems.

Inventive Principle:

Principle #35Parameter changes

2Stress or pressure

If upstream pressure is artificially increased to achieve pressure differential, then the required pressure differential can be achieved, but large quantities of fluid are required

Engineering Contradiction:

Improvepressure differentialVSAvoidfluid quantity

Core Design Contradiction:

Stress or pressureVSQuantity of substance

Solution Approach 1:

Rather than adding fluid to pressurize the upstream side, the patent removes fluid from the downstream side to depressurize it below ambient pressure. This inversion achieves the pressure differential with minimal fluid quantity requirements.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts fluid from the downstream side to create the pressure differential, rather than injecting large quantities of fluid into the upstream side. This extraction approach significantly reduces the total fluid quantity needed for testing.

Inventive Principle:

Principle #2Taking out (Extraction)

3Stress or pressure

If service line connects subsea tree to topside system for pressure manipulation, then pressure control is possible, but system complexity increases

Engineering Contradiction:

Improvepressure controlVSAvoidsystem complexity

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

The subsea pressure manipulation device performs pressure control functions directly at the subsea location, making the system self-sufficient. This eliminates the need for complex topside service lines and remote pressure manipulation systems.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent segments the pressure manipulation function from the topside control system and places it locally at the subsea tree. This segmentation reduces the complexity of the overall system by eliminating long service lines and remote control infrastructure.

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

This approach allows for safe and efficient valve testing by achieving the required pressure differential without the need for high-pressure pressurization, minimizing safety hazards and fluid usage, and enabling precise control of pressure differentials across the valve.

Implementation Method 1

after being isolated, depressurising the isolatable region to a pressure below an ambient, subsea pressure or pressurising the isolatable region using a pressure manipulation device positioned subsea

Methodology Applied

Scientific EffectPressure manipulation:

Data Source

PatentUS20240318745A1Subsea tree valve testing

Publication Date: 2024.09.26 EQUINOR ENERGY AS

AI summary

There is provided a method for testing a valve of a subsea tree. The method comprises: closing the valve to be tested; fluidly isolating an isolatable region of the subsea tree directly adjacent to the valve to be tested; after being isolated, depressurising the isolatable region to a pressure below an ambient, subsea pressure or pressurising the isolatable region using a pressure manipulation device positioned subsea; monitoring a pressure of the isolatable region after being depressurised; and determining whether the valve to be tested is operating correctly based on the monitoring.