Wellbore Isolation for Retrievable Motor Assemblies With Venting Control
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Solution Overview
Problem
Existing methods for hydraulic isolation in oil and gas wells, particularly when retrievable ESP systems are removed, often result in uncontrolled fluid communication between production tubing and the reservoir, leading to undesirable conditions such as gas migration and reduced well control.
Innovation Solution
A hydraulic isolation system comprising an isolation sleeve disposed within a wet connect mandrel and a vent assembly with a sliding sleeve, check valves, and an electrical, mechanical, or hydraulic actuation mechanism, which allows for controlled fluid flow and isolation when the ESP system is removed or installed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If straddle packers are used to isolate the wet connect mandrel assembly, then hydraulic isolation is achieved, but the flow profile through the inner diameter of the tubing string deteriorates and device complexity increases
Solution Approach 1:
The patent removes the straddle packers from the isolation system, extracting the harmful element that caused flow profile deterioration and device complexity. Instead, a simple isolation valve installed directly in the wet connect mandrel assembly provides the necessary hydraulic isolation without requiring additional packers or complex wellbore intervention equipment.
Solution Approach 2:
The isolation valve is integrated directly into the wet connect mandrel assembly, merging the isolation function with the existing mandrel structure. This eliminates the need for separate straddle packers and reduces device complexity while maintaining reliable hydraulic isolation capability.
2Reliability
If straddle packers are used to isolate the wet connect mandrel assembly, then hydraulic isolation is achieved, but the flow profile through the inner diameter of the tubing string deteriorates
Solution Approach 1:
The patent removes the straddle packers that were obstructing the tubular flow path. By extracting this harmful element and replacing it with an inline isolation valve, the full inner diameter flow profile is restored while hydraulic isolation remains effective.
3Ease of operation
If conventional venting ports are used to vent gas, then gas venting is achieved, but uncontrolled gas migration to the surface occurs when pump and motor are removed
Solution Approach 1:
The venting ports are equipped with movable closure elements (such as balls or plugs) that can dynamically open or close based on fluid pressure differentials. When the pump and motor are present, gas can vent freely; when removed, the ports close automatically to prevent uncontrolled gas migration, providing adaptive control without complex mechanisms.
Solution Approach 2:
The venting ports use self-actuating closure elements that respond automatically to pressure changes. When pressure differential exceeds a threshold, the closure elements seal the ports without requiring external control systems, preventing gas migration while maintaining ease of operation during normal venting conditions.
4Reliability
If plugs or valves are introduced in the well bore to provide tubing to surface isolation, then isolation is achieved, but the complexity of well completion design increases
Solution Approach 1:
The isolation valve is merged with the wet connect mandrel assembly, combining two functions (isolation and electrical connection) into a single integrated component. This eliminates the need for separate plugs or additional completion elements, reducing well completion design complexity while maintaining reliable isolation.
Solution Approach 2:
The wet connect mandrel assembly is designed to serve multiple functions: electrical power transmission, fluid flow conduit, and hydraulic isolation. By making the mandrel multi-functional, the patent eliminates the need for separate isolation devices, simplifying the overall well completion design.
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 system effectively prevents uncontrolled fluid communication, allowing for safe well operations, reduced gas migration, and minimized intervention requirements, thereby enhancing well completion design and operational efficiency.
Implementation Method 1
a check valve disposed within each of the plurality of vent ports
Implementation Method 2
The sliding sleeve is adapted to be electrically, mechanically or hydraulically actuated
Implementation Method 3
an isolation sleeve, wherein the isolation sleeve is disposed within a wet connect mandrel
Data Source
AI summary
A system and method for hydraulic isolation of a downhole powered system. The system and method include a sliding sleeve, venting assemblies with venting ports, and check valves associated with a vent body, and an isolation sleeve, isolation valve, and integral packer for controlling fluid flow through the motor and pump assembly of the powered system. Also disclosed is a wet connect mandrel modified to receive the isolation sleeve, the isolation sleeve preferably capable of permitting the passage of tools therethrough and capable of preventing fluid through the inlet of the mandrel. The mandrel may also be outfitted with a built-in sliding sleeve. The sleeves, valves and packer can be actuated mechanically, hydraulically or electrically. Electrical actuation can be facilitated using the power from an adjacent wet connect mandrel.