Vented Cap Stopper for Well Abandonment Gas Control
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Solution Overview
Problem
Current well abandonment methods face challenges in efficiently monitoring and controlling gas flows and preventing contamination during the surface abandonment of hydrocarbon wells, particularly due to lack of prescriptive regulatory requirements and issues with gas venting and groundwater influx, which can lead to corrosion and environmental hazards.
Innovation Solution
A system and method involving a vented cap with a stopper mechanism that allows casing gases to vent to the atmosphere, preventing wellbore fluid exchange and groundwater influx, using a steel plate with a hole and attached pipe section, and a coupler to house the stopper, which is positioned below the surface casing, allowing partial ejection under gas pressure and repositioning to seal, thus preventing environmental contamination and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a vented cap is installed to allow gas venting, then gas flow control is improved, but risk of wellbore fluid leakage and groundwater influx increases
Solution Approach 1:
A flexible membrane is installed within the vented cap assembly to selectively permit gas molecules to pass through while blocking larger wellbore fluid molecules and groundwater. The membrane's selective permeability allows vapor transmission while preventing liquid phase fluid exchange, thus maintaining reliability while enabling gas venting.
Solution Approach 2:
The flexible membrane acts as an intermediary barrier between the wellbore environment and the external atmosphere. It mediates the interaction by allowing beneficial gas venting while preventing harmful fluid infiltration, thus resolving the contradiction between gas flow control and fluid exchange prevention.
2Difficulty of detecting and measuring
If monitoring equipment is installed for gas flow monitoring, then detection capability is improved, but device complexity increases
Solution Approach 1:
The vented cap assembly incorporates passive monitoring capabilities that utilize the natural gas flow through the membrane to indicate pressure differentials and flow conditions. The system self-monitors by allowing gas to push against indicator mechanisms or flow sensors that require minimal power and complex electronics, thus improving detection while limiting complexity increase.
Solution Approach 2:
Complex electronic monitoring systems are replaced with simpler mechanical or physical indicators that respond to gas flow pressure and volume. For example, pressure-sensitive diaphragms or flow-driven mechanical gauges provide gas flow monitoring information without requiring sophisticated electronics, thereby improving detection capability while minimizing complexity addition.
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 solution effectively manages gas flows, prevents environmental contamination, and allows for safe abandonment of wells with minimal gas flow, meeting regulatory requirements while protecting the wellbore from corrosion and enabling gas sampling for analysis.
Implementation Method 1
allows casing gases to vent to atmosphere when sufficient pressure builds inside the casing or annulus
Implementation Method 2
prevents the exchange of wellbore fluid into the environment
Implementation Method 3
prevents the influx of groundwater into the casing strings
Data Source
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AI summary
The invention relates to a system and method for well abandonment, comprising installing a first steel plate comprising a hole having a pipe section attached above the hole, wherein a coupler may be installed to house a stopper which is then positioned below the surface casing having a second steel plate, the capping plate, affixed to the top of the surface casing. The stopper system then acts to prevent the exchange of wellbore fluid into the environment while allowing for proper venting of casing strings by pressure actuating the stopper system against the cap. The coupler further provides for attachment of various gas sampling or other monitoring equipment in for purposes of detection of leaks or other analytical objectives.