Two-Stage Diverter Spool Sleeve for High-Pressure Isolation
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Solution Overview
Problem
Existing diverter spools are unable to handle high pressures associated with blowout preventers (BOPs), requiring significant downtime and cost for removal before high-pressure operations, as they are limited to low-pressure or uncontrolled mud flow applications.
Innovation Solution
A two-stage diverter spool system with a movable sleeve that can be selectively opened or closed using a handling tool, allowing low-pressure outlets to be accessed or isolated without removing the diverter from the wellhead assembly, enabling continuous operation with the BOP stack and riser system intact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a diverter spool is used for low-pressure mud flow applications, then the diverter can handle uncontrolled or hydrostatic head pressure applications, but the diverter cannot handle high pressures associated with blowout preventers and must be removed before high-pressure operations
Solution Approach 1:
The diverter spool is segmented into two distinct stages: a first diverter spool with low-pressure outlets for uncontrolled applications, and a second diverter spool with high-pressure outlets for BOP operations. This segmentation allows each stage to be optimized for its specific pressure range, and the system can transition between stages without removing the entire diverter assembly, thereby resolving the contradiction between pressure handling versatility and operational continuity
Solution Approach 2:
A movable sleeve is introduced that can dynamically block or open access to the low-pressure outlets. The sleeve is positioned to block the low-pressure outlets when the second diverter spool is installed, and can be moved to open access when needed. This dynamic control mechanism allows the system to adapt its configuration based on operational requirements, enabling high-pressure operations without diverter removal while maintaining the option for low-pressure operations
2Adaptability or versatility
If the diverter is removed from the wellhead assembly to permit high pressure flow through the BOP, then high-pressure operations can be performed, but significant downtime and cost are incurred
Solution Approach 1:
The diverter system is divided into two functional stages that can operate independently or in sequence. The first stage handles low-pressure operations, and the second stage handles high-pressure operations. This segmentation eliminates the need to remove the entire diverter assembly for high-pressure operations, as the system can simply transition to using the second diverter spool, thereby maintaining productivity while achieving high-pressure capability
Solution Approach 2:
The wellhead assembly is designed with universal compatibility for both low-pressure and high-pressure operations through the two-stage diverter configuration. The same wellhead assembly can accommodate either the first diverter spool for low-pressure applications or the second diverter spool for high-pressure applications, eliminating the need for different assemblies or removal operations and thus improving rig time efficiency
3Ease of operation
If low pressure outlets are always open for mud flow diversion, then cuttings/mud can be diverted to mud pits without passing through the BOP stack, but the outlets cannot be closed when BOP control is required
Solution Approach 1:
A movable sleeve is positioned within the diverter spool to dynamically control access to the low-pressure outlets. The sleeve can be moved between positions to either block or open the outlets as needed. When the second diverter spool is installed for high-pressure operations, the sleeve is positioned to block the low-pressure outlets, preventing mud flow diversion and ensuring all flow passes through the BOP stack for proper control. When low-pressure operations are required, the sleeve can be moved to open the outlets, restoring the diversion capability
Data Source
AI summary
A wellhead system diverter spool contains an internal sleeve that can be axially shifted internal to the spool with a handling tool. The sleeve permits access to outlets in the spool when required. When higher pressures are required, the internal sleeve is shifted downward to close off access to the outlets without change out of equipment or changing the BOP stack riser system. The low pressure lines connected to the outlets can remain installed but are isolated from the higher pressure BOP stack pressures.