Surface-Controlled Gas Vent System for Horizontal Well Slugging
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Solution Overview
Problem
Horizontal wells with terrain-induced slugging issues due to gas and liquid flow unsteadiness, leading to pressure buildup and pump damage, are not effectively addressed by conventional mechanical valves and gas-permeable membranes, which face reliability problems and inefficiencies.
Innovation Solution
A gas vent system with a gas vent conduit and probe conduit, controlled by a controller that adjusts valve positions based on flow measurements to efficiently remove gaseous substances from the wellbore, bypassing the pump and maintaining a constant pressure, thereby preventing slug formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical valves are used in the gas vent tube to prevent liquid ingress and allow gas escape, then gas venting function is improved, but reliability deteriorates due to valve failure under harsh downhole conditions
Solution Approach 1:
The invention extracts the valve from the downhole environment and relocates it to the surface. The gas vent tube extends from the wellbore to the surface where a valve is positioned. This allows the valve to operate in benign surface conditions rather than harsh downhole conditions, dramatically improving reliability while reducing the complexity of downhole equipment.
Solution Approach 2:
The gas vent tube acts as an intermediary conduit that transports gas from the downhole wellbore to the surface valve. This intermediary structure allows the separation of the gas collection function (downhole) from the gas control function (surface), enabling the valve to be positioned where conditions are favorable for reliable operation.
2Reliability
If gas-permeable membranes are used to allow gas passage while blocking liquid, then gas venting is improved, but reliability deteriorates due to fouling from sand and debris
Solution Approach 1:
The invention removes the need for gas-permeable membranes by using a physical separation approach instead. The gas vent tube is positioned to collect gas at the peak of the wellbore elevation where gas naturally accumulates, and the surface valve controls gas release. This eliminates the membrane component that would be susceptible to fouling from sand and debris.
Solution Approach 2:
Instead of using a membrane that tries to selectively pass gas while blocking liquid (which gets fouled), the invention inverts the approach by using gravity and elevation to naturally separate gas from liquid. Gas collects at the peak elevation and is vented through the tube, while liquid remains in the wellbore, eliminating the need for selective permeability components.
3Productivity
If active mechanical valves with sensors are used to automatically control gas venting, then gas venting efficiency is improved, but device complexity deteriorates due to power supply requirements
Solution Approach 1:
The system uses passive, automatic valve operation based on pressure differential rather than active electronic control. The valve opens automatically when gas pressure builds up enough to overcome the valve spring force, and closes when pressure equalizes. This self-service mechanism eliminates the need for sensors, power supplies, and electronic control systems, maintaining high venting efficiency without the complexity of active components.
Solution Approach 2:
The invention replaces complex electronic control systems (sensors, microcontrollers, power supplies) with a simple mechanical pressure-responsive valve system. The valve's opening and closing are directly controlled by the gas pressure itself through mechanical force balance, eliminating the need for electrical power and electronic components while maintaining effective gas venting.
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 reduces gas slug formation, enhances liquid flow rates, prolongs pump operational life, and maximizes hydrocarbon recovery by maintaining a constant minimum pressure along the wellbore.
Implementation Method 1
The gas-permeable membrane may be pressure differential induced or merely allow gas molecules of particular sizes passage through the membrane
Implementation Method 2
A gas vent valve coupled to the gas vent conduit and situated outside the wellbore. The gas vent valve controls the flow of gaseous substances through the gas vent conduit.
Implementation Method 3
The system effectively reduces gas slug formation, enhances liquid flow rates, prolongs pump operational life, and maximizes hydrocarbon recovery by maintaining a constant minimum pressure along the wellbore.
Data Source
AI summary
A gas vent system for use in a wellbore that includes a substantially horizontal portion is provided. The gas vent system includes a gas vent conduit positioned within the wellbore. The gas vent conduit defining a gas vent intake passage situated within the substantially horizontal portion of the wellbore and configured to facilitate a flow of gaseous substances therethrough. A gas vent valve coupled to the gas vent conduit and situated outside the wellbore. The gas vent valve controls the flow of gaseous substances through the gas vent conduit.