Drum Unit with Pivotable Axis for Well Intervention Tension Control

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Solution Overview

Problem

Existing well intervention operations face issues with fleet angle variations and relative speed differences between the drum and injector head, leading to undesired tension variations and potential damage to cables or equipment.

Innovation Solution

A drum unit with a structural frame that allows lateral translation of the drum and incorporates a tension compensator with a guide arch, which is displaceable to maintain a constant tension and compensate for speed variations, ensuring the intervention string runs straight and avoids lateral shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a laying guide imposes a fleet angle on the intervention string, then the string can be directed onto the drum, but tension variations occur due to fleet angle variation

Engineering Contradiction:

Improvestring direction controlVSAvoidtension stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The drum axis is made pivotable rather than fixed, allowing the drum to dynamically adjust its orientation to maintain the intervention string perpendicular to the drum surface. This dynamic adjustment eliminates fleet angle variations and the resulting tension fluctuations, resolving the contradiction between ease of operation and tension stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system incorporates a feedback mechanism where the position of the intervention string on the drum influences the drum axis orientation. As the string position changes during winding/unwinding operations, the pivotable axis automatically adjusts to maintain optimal alignment, creating a self-regulating system that prevents tension variations.

Inventive Principle:

Principle #23Feedback

2Productivity

If the drum rotation speed is kept constant, then the winding operation is simplified, but fleet angle variation causes tension variation

Engineering Contradiction:

Improvewinding speed consistencyVSAvoidtension stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

By making the drum axis pivotable, the system allows constant drum rotation speed to be maintained while dynamically adjusting the drum orientation to compensate for changes in string position. This eliminates the need to vary rotation speed and prevents tension variations caused by fleet angle changes.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the injector head stops suddenly during hauling operation, then the cable feed is controlled, but the drum's rotational inertia causes continued cable feed and potential damage

Engineering Contradiction:

Improvecable feed controlVSAvoidcable damage risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The pivotable drum axis acts as an intermediary mechanism between the drum's rotational inertia and the cable feed control. When the injector head stops suddenly, the drum axis can pivot to absorb the inertia-induced speed differential, preventing direct transmission of harmful forces to the cable and injector head.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system provides inherent cushioning against sudden stops through the pivotable axis mechanism. This mechanical flexibility anticipates and absorbs inertia effects before they can cause damage, protecting the cable and equipment from harmful forces.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Adaptability or versatility

If a free air arc is used to compensate for speed differences, then the intervention string can absorb speed variations, but safety risks increase due to swinging movements

Engineering Contradiction:

Improvespeed variation absorptionVSAvoidswinging movement danger

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The pivotable drum axis serves as a controlled intermediary that absorbs speed variations mechanically through pivoting motion, replacing the uncontrolled free air arc approach. This provides the same adaptability for speed compensation while eliminating safety hazards associated with swinging cable movements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9169102B2Drum unit for a well intervention string

Publication Date: 2015.10.27 STIMLINE

AI summary

A drum unit for an intervention string for a well includes a drum with a radius for the intervention string, arranged in a structural frame and rotatable by a motor, the drum being arranged translating along a drum axis and driven by a translation motor, for controlled winding of the intervention string onto the drum relative to a first, fixed guide in the structural frame. A compensator includes a guide arch, the guide arch being displaceable in a direction orthogonal to the drum axis using a force device at the structural frame. The intervention string runs between the guide arch and the first fixed guide to or from a first end of the guide arch to the drum. The intervention string runs via a second, opposite end of the guide arch via a second, fixed guide at the structural frame, to or from the well.