Background
In the field of hydrocarbon production, artificial-lift systems are used to enhance the extraction of oil and gas from reservoirs. As reservoirs deplete over time, their natural pressure diminishes, making it increasingly difficult to bring hydrocarbons to the surface. Artificial-lift techniques, which include the use of pumps and gas injection, are essential to maintain and improve production rates. These systems add energy to the fluid column within the wellbore, facilitating the upward movement of oil, water, and gas. Among the various artificial-lift methods, electric submersible pumps (ESPs), beam pumps, and progressing cavity pumps (PCPs) are commonly used. Each of these pumps has its own advantages and limitations, particularly when dealing with mixed-phase fluids containing both liquid and gas. The need for efficient separation of gas and liquid phases before pumping is critical to ensure the optimal performance of these artificial-lift systems.
Current approaches to gas-liquid separation in artificial-lift systems face several challenges. When the pump intake is positioned above the producing interval, gas interference becomes a significant issue. Gas liberated from the solution can form foam, which occupies a large volume within the wellbore casing and reduces the pump's liquid intake efficiency. Gas separators are often used to mitigate this problem, but their effectiveness is limited by the volume of foam and the available space within the casing annulus. Additionally, in horizontal wells where the pump intake is typically above or within the producing interval, the separation of gas from liquid is less efficient, leading to decreased pumping performance. The presence of foam and free gas in the pump intake can significantly reduce the pump's fillage and overall efficiency. Moreover, the limited capacity of gas separators to handle large volumes of gas further exacerbates the problem, making it difficult to maintain consistent and efficient production rates.
Technology Overview
The gas-liquid separator/connector described is a sophisticated device designed to enhance the efficiency of hydrocarbon production by separating gas from liquid in downhole environments. It features a three-concentric tube design where fluids from an Electric Submersible Pump (ESP) enter through the bottom and are directed into the largest of the three tubes. The relatively large space between the inner and outer tubes facilitates the separation of gas from the liquid. The gas rises to the surface through the tubing-casing annulus, while the liquid, driven by gravity, enters the third tube situated between the inner and outer tubes. This third tube, shorter than the outer tube, channels the liquid to the pump intake for either a beam pump or a Progressive Cavity Pump (PCP), which is part of the smallest inner tube of the connector.
This technology is differentiated by its ability to combine multiple artificial lift methods, thereby improving the overall efficiency and performance of downhole pumps. The three-concentric tube design allows for effective separation of gas and liquid, which is crucial in wells with high gas-to-oil ratios. By ensuring that only liquid enters the beam pump or PCP, the device minimizes gas interference, which can significantly reduce pump efficiency and increase wear. Additionally, the system allows for the use of an ESP to handle small liquid volumes and some gas from horizontal sections of a well, while the beam pump or PCP, installed in the vertical section, lifts the liquid to the surface. This combination maximizes the production rate and extends the economic life of low-pressure, low-volume wells.
Benefits
- Improves the rate of production of hydrocarbons using a combination of artificial-lift techniques.
- Allows for the separation of gas from liquid, enhancing pump efficiency.
- Reduces wear and service intervals of the pumps.
- Enables the use of multiple artificial-lift technologies simultaneously.
- Facilitates the pumping of low volume and low-pressure liquids in horizontal wells.
- Provides a gas-free liquid stream to the beam pump intake.
- Maximizes the flow rate from the reservoir by achieving the lowest producing pressure.
- Ensures only liquid enters the beam pump or progressive cavity pump while gas continues to the surface.
- Allows for continued production in low volume horizontal oil wells by using two pumps in optimal well sections.
Applications
- Hydrocarbon production optimization
- Gas-liquid separation
- Artificial lift systems
- Downhole fluid management
Patents
U.S. Pat. No. 10,280,728
