Greaseless Triple Packoff Assembly for High-Pressure Wireline Operations

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Solution Overview

Problem

The oil and gas industry faces challenges in maintaining effective pressure control during wireline operations, particularly with the shift to greaseless, coated wireline cables, as traditional pressure control equipment is inadequate for high-pressure applications and requires frequent maintenance.

Innovation Solution

A greaseless triple packoff assembly with a slim body design, metal bushings, and a pressure transducer system that includes velocity check-valves and a hydraulic operation, capable of withstanding up to 15,000 psi, eliminating the need for grease injection and reducing maintenance requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional pressure control equipment is used with greaseless coated wireline cables, then the equipment becomes inadequate for high-pressure applications, but switching to specialized greaseless equipment increases device complexity

Engineering Contradiction:

Improvepressure control effectivenessVSAvoidequipment structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The packoff assembly is divided into multiple independent packoff elements (first, second, and third packoff elements) that can be selectively activated. Each element contains its own piston, resilient sealing member, and hydraulic chamber, allowing the system to segment the sealing function across multiple units rather than requiring a single complex sealing mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The packoff assembly performs multiple functions: it provides pressure sealing around the wireline cable, enables wireline movement in and out of the wellbore, monitors pressure via transducers, and can selectively activate different packoff elements. The hydraulic system serves both to activate packoff elements and to monitor pressure conditions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If traditional pressure control equipment is used, then initial setup is simpler, but maintenance requirements increase frequently

Engineering Contradiction:

Improveequipment setupVSAvoidmaintenance frequency

Core Design Contradiction:

Ease of manufactureVSEase of repair

Solution Approach 1:

The velocity check-valves automatically prevent fluid from escaping the well when the wireline is removed, without requiring manual intervention. The hydraulic system automatically activates packoff elements when pressure is detected, and the resilient sealing members self-adjust to maintain sealing around the wireline cable during movement.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The resilient sealing members are pre-positioned to engage with the wireline cable before high-pressure operations begin. The hydraulic system is pre-configured to activate packoff elements in sequence, and velocity check-valves are pre-installed to prevent fluid escape before it can cause damage.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If real-time pressure monitoring is implemented, then operational safety improves, but device complexity increases

Engineering Contradiction:

Improveoperational safetyVSAvoidmonitoring system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Pressure transducers are installed to detect pressure within the hydraulic chamber and provide real-time feedback to the control system. When pressure is detected, the system automatically activates the appropriate packoff elements by directing hydraulic fluid to their chambers, creating a closed-loop feedback control system that responds dynamically to pressure conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system uses hydraulic fluid to both monitor pressure conditions and activate packoff elements. The hydraulic chamber serves as both the pressure sensing medium and the actuation mechanism, eliminating the need for separate electrical sensors and actuators.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 provides reliable pressure control, extends the life of the wireline cable, and minimizes operational mistakes by enabling real-time pressure monitoring and automatic switching between packoff elements, ensuring safe and efficient high-pressure operations.

Implementation Method 1

a first resilient sealing member, which is between the first upper bushing and the first lower bushing

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a first piston coupled to a first port... configured to slide towards the first resilient sealing member to compress the first resilient sealing member

Methodology Applied

Scientific EffectHydraulic pressure: Pascal's Law