Pack-off Assembly Sleeve Positioning for Wireline Seal Access
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Solution Overview
Problem
The existing pressure-control equipment for oil/gas wells requires time-consuming and costly seal replacement, often necessitating disassembly of the PCE stack and cutting of the wireline, which is error-prone and inefficient.
Innovation Solution
A pack-off assembly with a positionable sleeve and actuation chambers that use pressurized fluids to selectively position the sealing elements, allowing for quick seal access and replacement without disassembling the stack or cutting the wireline, featuring a retractable side-door sleeve and multi-part sealing elements with dowel pins for alignment and a wireline entry guide for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If seal replacement is performed using existing pressure-control equipment, then the sealing function is restored, but the process requires disassembly of the PCE stack and cutting of the wireline, which is time-consuming and costly
Solution Approach 1:
The pack-off assembly is divided into separable components including a body, a sleeve that can be independently positioned, and a sealing element. The sleeve can be moved between open and closed positions to expose or contain the sealing element, allowing seal replacement without disassembling the entire PCE stack. This segmentation enables the sealing function to be maintained while facilitating quick access to the seal for replacement.
2Ease of operation
If the PCE stack is disassembled for seal replacement, then the sealing element can be accessed, but the complexity of the procedure increases and errors may occur
Solution Approach 1:
The sleeve is designed to be dynamically positionable between an open position (exposing the sealing element) and a closed position (containing the sealing element). This dynamic positioning is achieved through actuation chambers that can be pressurized to move the sleeve, allowing operators to access the sealing element without disassembling the PCE stack, thereby simplifying the maintenance procedure while maintaining accessibility.
3Ease of repair
If wireline cutting is performed during seal replacement, then the old seal can be removed, but the risk of errors and operational disruptions increases
Solution Approach 1:
The sealing element is extracted from within the pack-off assembly by positioning the sleeve in the open position, which exposes the sealing element for removal. This extraction is performed without cutting the wireline, as the sealing element can be independently accessed and replaced. The wireline remains intact and connected, maintaining operational reliability while enabling easy seal replacement.
4Reliability
If the sleeve is made stationary to maintain pressure control, then pressure containment is ensured, but the sealing elements cannot be accessed for replacement
Solution Approach 1:
The sleeve transitions from a stationary design to a dynamic one, capable of moving between closed (pressure containment) and open (seal access) positions. This is achieved through actuation chambers that can be pressurized to move the sleeve, allowing the system to maintain pressure control reliability when needed while providing ease of operation for seal replacement when required.
Solution Approach 2:
Actuation chambers are incorporated into the pack-off assembly, which can be pressurized with fluid to move the sleeve between positions. This pneumatic/hydraulic actuation mechanism enables the sleeve to be positioned for seal access without compromising the pressure control reliability when the sleeve is in the closed position, as the same fluid pressure system maintains the sealing force.
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
Enables rapid and error-free seal replacement, reducing operational time and costs by allowing selective positioning of the sleeve for closed or open positions using pressurized fluids, maintaining pressure control without disassembly or wireline cutting.
Implementation Method 1
Application of pressurized fluids to one or both of the activation chambers can yield a pressure differential across the piston, causing the piston (and the sleeve) to move within the support element's cavity
Implementation Method 2
pressurized fluids may be selectively applied to actuation chambers of the pack-off assembly to position the sleeve in a closed position, in which the sealing element is enclosed by the sleeve
Data Source
AI summary
The described pack-off assembly includes a tubular sleeve that is configured to selectively encompass a pack-off wireline seal and that is positionable through selective application of pressurized fluid to one or more actuation chambers that interact with a piston portion of the sleeve. Pressure may be applied to position the sleeve to encompass the seal to engage a wireline and enable pressure-control wireline operations. A different pressure may be applied to position the sleeve to expose the seal for servicing.