Wellhead Isolation Sleeve for High-Pressure Fracturing
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Solution Overview
Problem
Wellhead components are often damaged by high-pressure and abrasive fracturing fluids during well fracturing operations due to their inability to handle pressures exceeding their rated capacity, and existing isolation sleeves do not adequately protect these components from erosion and damage.
Innovation Solution
An isolation sleeve assembly with a seal carrier and hydraulic piston system that can be inserted into the wellhead, allowing for the isolation of high-pressure fracturing fluids from sensitive areas by moving the seal into and out of contact with the well conduit using hydraulic pressure, enabling the sleeve to be retrieved after the operation and eliminating the need for a secondary packoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the wellhead is used for high-pressure fracturing operations, then the fracturing operation can be performed, but the wellhead components are damaged by high pressure and abrasive fluids
Solution Approach 1:
The isolation sleeve divides the wellhead internal space into two separate zones: a high-pressure zone where fracturing fluid is injected, and a protected zone containing sensitive wellhead components. This segmentation allows the high-pressure fracturing operation to proceed while physically isolating the components that cannot withstand such pressures, thus resolving the contradiction between achieving high fracturing pressure and maintaining component integrity.
Solution Approach 2:
The isolation sleeve acts as an intermediary barrier between the high-pressure fracturing fluid and the sensitive wellhead components. This intermediate structure absorbs the harsh conditions (high pressure and abrasive fluids) that would otherwise directly damage the components, allowing the fracturing operation to proceed at full pressure while protecting the components from direct exposure to damaging conditions.
2Reliability
If an isolation sleeve is installed to protect wellhead components, then component protection is improved, but the device complexity increases
Solution Approach 1:
The sealing function is extracted from the main isolation sleeve body and implemented as a separate, removable seal carrier assembly. This allows the seal to be independently replaced or maintained without removing the entire isolation sleeve, simplifying maintenance operations and reducing overall system complexity while maintaining effective component protection.
Solution Approach 2:
The seal carrier is designed to be movable along the isolation sleeve, transitioning between a retracted position during installation/removal and an extended position during operation. This dynamic design allows the seal to engage with the well conduit only when needed, simplifying the installation and retrieval processes while maintaining protection during the fracturing operation.
3Reliability
If the seal is rigidly fixed in the isolation sleeve, then sealing reliability is improved, but the ease of retrieval and reuse is reduced
Solution Approach 1:
The sealing system is segmented into a movable seal carrier and a stationary isolation sleeve body. This segmentation allows the seal carrier to be independently manipulated - it can be extended to engage the well conduit for sealing, then retracted to allow retrieval of the isolation sleeve. The seal maintains reliable contact with the well conduit during operation while enabling easy retrieval and reuse of the sleeve assembly.
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
Effectively isolates high-pressure fracturing fluids from wellhead components, preventing damage and allowing for safe operation at pressures beyond the rated capacity of standard wellhead seals, while enabling easy retrieval and reuse of the isolation sleeve.
Implementation Method 1
The seal carrier has an energizing piston that, when supplied with hydraulic fluid, moves the seal carrier downward, energizing the seal against the rim of the well conduit.
Implementation Method 2
When hydraulic pressure is supplied to the energizing piston, it pushes the engaging member down to energize the seal against the outer diameter of the conduit.
Data Source
AI summary
An isolation sleeve extends from an adapter into the bore of a tubing head to isolate high pressure frac fluid from the body of the tubing head. The isolation sleeve may be moved into and out of the bore by a hydraulic transfer piston or it may be installed and retrieved by a running tool. The isolation sleeve has a seal carrier on its lower end. The seal of the seal carrier may seal to a secondary packoff in the tubing head, on the outer diameter of the conduit, or to the rim of the conduit. The seal carrier may be movable relative to the sleeve to energize the seal.