Downhole Venturi Gas Extraction for Pump Reliability
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Solution Overview
Problem
Current methods for gas extraction in oilfield applications, such as using high head centrifugal pumps, face issues with gas lock conditions that lead to pump failure and reduced efficiency, as they require manual adjustment of production rates and lack effective mechanisms to incorporate gas into the liquid stream for enhanced flow assurance.
Innovation Solution
A gas extraction device utilizing a venturi mechanism within the tubing to create a low-pressure area, drawing gas into the liquid stream and reducing the burden on the pump by leveraging buoyancy and pressure balance, allowing for automated control of gas-liquid interface levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high head centrifugal pump is used to pump liquid, then the liquid production rate increases, but gas lock conditions occur causing pump failure and reduced reliability
Solution Approach 1:
The gas extraction device extracts gas from the liquid stream using a venturi mechanism that creates a low-pressure area to draw gas into the liquid stream, separating gas from liquid before it reaches the pump, thereby preventing gas lock conditions
Solution Approach 2:
The venturi device acts as an intermediary between the well and the pump, creating a pressure differential that facilitates gas-liquid separation and prevents gas from entering the pump, thus maintaining reliable pump operation
2Reliability
If the production rate is manually adjusted to prevent gas lock, then pump reliability improves, but productivity decreases due to reduced fluid production
Solution Approach 1:
The gas extraction device automatically manages gas-liquid separation without requiring manual intervention, using the natural flow of liquid and pressure differentials to continuously remove gas, thereby maintaining both high productivity and reliable pump operation
3Reliability
If the venturi is located high in the well to evacuate gas from the casing annulus, then gas extraction effectiveness improves, but the pressure differential required to entrain gas is harder to achieve
Solution Approach 1:
The device allows dynamic positioning of the venturi assembly axially to adjust the location of the gas entrainment port, enabling optimization of the pressure differential and gas extraction effectiveness based on operating conditions
4Reliability
If gas is vented at the well head to a separate gathering system, then gas removal is effective, but the system complexity increases and requires additional infrastructure
Solution Approach 1:
The gas extraction device merges gas removal with the existing liquid production stream by using the venturi to draw gas into the liquid stream, eliminating the need for separate gas venting infrastructure and reducing system complexity
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 enhances pump performance by reducing gas lock occurrences, increasing fluid production, and improving flow assurance through automated control of gas entrainment, particularly beneficial in subsea applications where traditional gas removal methods are not feasible.
Implementation Method 1
A venturi creates a low pressure area through a constricted section of the tubing. The pressure within the throat of the venturi drops lower than the pressure in the casing.
Implementation Method 2
The pressure within the throat of the venturi drops lower than the pressure in the casing. The lower pressure in the venturi draws the gas into the liquid stream
Implementation Method 3
As the gas enters the flowing liquid in the tubing it lightens the liquid and begins to add buoyancy to the vertical flow forces.
Data Source
AI summary
A gas extraction device for down hole oilfield applications utilizes the flow of the liquid, created by an artificial lift device, to produce conditions by which the gas is drawn into tubing. A venturi creates a low pressure area through a constricted section of the tubing. The pressure within the throat of the venturi drops the pressure in the casing. The device is axially adjusted to allow communication ports to a lower pressure area of the casing annulus. The lower pressure in the venturi draws the gas into the liquid stream and into the production tubing above the device. The gas is then transferred through the well head within the liquid stream.