Subsurface Safety Valve Pressure Control via Annulus Fluid Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Subsurface safety valves in subterranean wells face challenges due to leaks and wear in control lines, leading to inefficient fluid flow control and potential premature closure, which can disrupt hydrocarbon production.
Innovation Solution
A well system that uses a control unit to monitor temperature and pressure in the tubing-casing annulus, calculating thermal expansion or contraction to maintain optimal pressure and automatically adjust fluid volumes to control the subsurface safety valve, eliminating the need for control lines by using a surface tank, pump, and valves to manage fluid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control lines are used to operate the subsurface safety valve, then the valve can be controlled to close in emergencies, but leaks and wear in control lines lead to premature closure and reduced reliability
Solution Approach 1:
The invention removes the control line from the system entirely. Instead of using a control line to transmit hydraulic pressure from the surface to the subsurface safety valve, the system uses the tubing-casing annulus as the pressure transmission medium. This extraction of the control line eliminates the source of leaks and wear associated with it.
Solution Approach 2:
The tubing-casing annulus, which already exists as part of the wellbore structure for other purposes (such as cementing and isolation), is repurposed to serve as the pressure transmission medium for operating the subsurface safety valve. This multi-functional use eliminates the need for dedicated control lines.
2Reliability
If thermal expansion and contraction of fluid in the tubing-casing annulus is not compensated, then the system structure remains simple, but pressure fluctuations cause premature valve closure
Solution Approach 1:
The system incorporates temperature and pressure sensors that continuously monitor the fluid in the tubing-casing annulus. The control unit receives this data and calculates thermal expansion or contraction, then determines the volume of fluid needed to maintain optimal pressure. This feedback loop ensures the valve operates reliably despite temperature changes.
Solution Approach 2:
The system automatically adjusts fluid volume in response to thermal changes without requiring manual intervention. The control unit autonomously calculates the required fluid volume and activates the pump or release valve as needed, allowing the system to self-correct pressure fluctuations caused by thermal expansion and contraction.
3Productivity
If manual fluid volume adjustment is used in the tubing-casing annulus, then the system structure remains simple, but pressure control is inefficient and time-consuming
Solution Approach 1:
The system automatically monitors pressure and temperature, calculates the required fluid volume adjustments, and executes the adjustments without human intervention. The control unit manages the entire process, from sensing conditions to activating the pump or release valve, significantly improving pressure control efficiency.
Solution Approach 2:
The system replaces manual mechanical fluid adjustment with an automated control system that uses sensors, processors, and automated pumping mechanisms. This substitution of manual operations with automated systems increases productivity and precision in pressure management.
4Productivity
If fluid is not added or released in response to thermal expansion, then maintenance needs are reduced, but pressure deviations disrupt normal operations
Solution Approach 1:
The system automatically manages fluid volume in the tubing-casing annulus by monitoring pressure and temperature conditions. When thermal expansion or contraction occurs, the control unit calculates the required fluid volume adjustment and activates the pump or release valve accordingly, maintaining optimal pressure for continuous hydrocarbon production.
Solution Approach 2:
The system dynamically adjusts fluid volume based on changing temperature and pressure parameters. By monitoring these parameters and responding with appropriate fluid additions or releases, the system maintains pressure within the optimal range required for normal valve operation and uninterrupted hydrocarbon production.
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
This solution enhances fluid flow control efficiency, reduces the risk of leaks and premature valve closure, and minimizes maintenance needs, ensuring reliable operation and optimal pressure management within the tubing-casing annulus.
Implementation Method 1
calculating an expected thermal expansion or contraction of the fluid in the tubing-casing annulus based on the received measurements
Implementation Method 2
transmitting a signal to activate a release valve to release, from the tubing-casing annulus, a volume of fluid sufficient to cause the subsurface safety valve to switch from the open state to the closed state
Data Source
AI summary
The well system includes a casing and production tubing and a control unit that can receive measurements of temperature and pressure of fluid in the tubing-casing annulus (TCA). A subsurface safety valve (SSSV) connected to the tubing can switch to an open or closed state in response to a change in pressure of the fluid. An expected thermal expansion or contraction of the TCA fluid is calculated based on the received measurements, and the control unit determines, based on the expected thermal expansion or contraction and on a calculated TCA volume, a volume necessary to be added to or released from the TCA to maintain the fluid within an optimal pressure range. The control unit can also receive an indication of an emergency condition and transmit a signal to activate a release valve to release from the TCA a volume of fluid sufficient to cause the SSSV to close.