Wellhead Assembly for Hydraulic Pumping System Control
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Solution Overview
Problem
Existing in-casing hydraulic drive units for oil wells lack adequate wellhead control and isolation of hydraulic supply lines, particularly in environments with stringent regulatory emissions controls.
Innovation Solution
A wellhead assembly that includes pressure-containing body members, a hydraulic pump hanger to suspend and seal the hydraulic cylinder, hydraulic fluid supply lines with check valves, and a valve actuating stem to control fluid flow, ensuring secure and controlled operation of the hydraulic drive unit within the wellhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an in-casing hydraulic drive unit is installed within the well casing, then the stuffing box is eliminated and hydraulic pumping is achieved, but adequate wellhead control and isolation of hydraulic supply lines are not provided
Solution Approach 1:
The wellhead assembly is divided into distinct functional components: a wellhead body, a hydraulic pump hanger, check valves, and isolation mechanisms. This segmentation allows each component to perform its specific function independently while maintaining overall system control and reliability without excessive complexity.
Solution Approach 2:
A hydraulic pump hanger is introduced as an intermediary component between the wellhead and the hydraulic drive unit. This hanger provides the necessary connection, sealing, and isolation functions, enabling wellhead control without requiring direct integration that would increase complexity.
2Ease of operation
If hydraulic supply lines are integrated within the well casing, then in-casing hydraulic pumping is enabled, but isolation from production and control over hydraulic lines are insufficient
Solution Approach 1:
Check valves are pre-installed within the hydraulic pump hanger to establish isolation from production before hydraulic operations begin. This preliminary action ensures that production fluids cannot contaminate the hydraulic system, maintaining reliability while enabling ease of operation.
Solution Approach 2:
The hydraulic pump hanger provides localized isolation and control functions at the specific point where hydraulic lines enter the well casing. This local quality approach ensures reliable isolation where needed most without requiring complex system-wide controls.
3Ease of manufacture
If a landing spool is bolted onto the wellhead to land the hydraulic drive unit hanger, then the drive unit can be installed, but adequate wellhead control is not provided
Solution Approach 1:
The wellhead control functions and the drive unit landing functions are merged into a single integrated wellhead assembly. The hydraulic pump hanger combines the landing function with isolation and control capabilities, maintaining installation simplicity while providing adequate wellhead control through functional integration.
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 wellhead assembly provides effective well control and isolation of hydraulic supply lines, ensuring safe and regulated operation of the in-casing hydraulic drive unit, addressing the need for enhanced control and compliance with emissions regulations.
Implementation Method 1
provide a check valve sealed in each hydraulic inlet port
Implementation Method 2
a hydraulic pump hanger retained and sealed within the vertical bore of the one or more wellhead body members
Implementation Method 3
one or more hydraulic fluid supply lines providing hydraulic fluid to drive the driven element
Data Source
AI summary
A wellhead assembly to seal and suspend an in-casing hydraulic drive unit for a downhole pump, including pressure-containing wellhead body members with a vertical bore and a production bore at its uppermost portion. A hydraulic pump hanger is retained and sealed in the vertical bore. The hydraulic pump hanger suspends and seals the hydraulic cylinder, includes a bore extending vertically therethrough, forms at least one hydraulic line to communicate with hydraulic fluid supply lines, forms a hydraulic inlet port to each hydraulic line, and provides a check valve sealed in each hydraulic inlet port. The wellhead body member(s) includes a stem port aligned with each hydraulic inlet port, with a valve actuating stem sealed in each stem port to actuate each check valve between a normally closed and open position. The wellhead body member(s) also includes hydraulic injection port(s) formed to supply hydraulic fluid to each hydraulic inlet port.