For over a century, gas lock has plagued the oil industry, disrupting fluid production and raising costs. Wells with excessive gas or volatile fluids face reduced productivity and potential equipment damage. Understanding the gravity of gas lock requires dissecting standard pump operations and delineating the anomalies introduced by this issue.
In typical pump operations, the plunger's descent builds pressure within the chamber, forcing the traveling valve to open, allowing fluid escape. However, "normal" pump operation is often disrupted by gas lock. During gas lock, the plunger's descent keeps the traveling valve closed, creating a low-pressure zone. Gas enters the pump, and the standing valve closes. As the plunger descends, the gas fails to open the traveling valve. With the valve closed, no vacuum forms to open the standing valve, leading to pump wear and requiring replacement.
Identifying the issue in the "gas lock" cycle is the first step to a solution. Gas lock occurs because the traveling valve fails to open. To address this, it's crucial to ensure the traveling valve opens during each descent and remains open. Additionally, a robust relative vacuum must be established during the upstroke to force open the standing valve. A device that positively opens the traveling valve during the downstroke and keeps it open while creating a strong relative vacuum during the upstroke is needed. These solutions must work in harmony to break the cycle.
The DARTT Valve is the key to overcoming these problems. It uses hydraulic principles, leveraging pressure on a larger area to generate a greater force, to ensure the traveling valve opens at the downstroke's start and remains open throughout the descent. During the upstroke, the DARTT Valve ensures the traveling valve and its cascade valves close securely, creating a nearly perfect relative vacuum. The pressure differential prompts the standing valve to open, ensuring the pump fills with well fluid.
This sequence transforms a standard plunger pump into one capable of handling gas. While pumping gas might not be cost-effective, the DARTT Valve allows the pump to handle it efficiently. The key is to pump gas long enough to prime the pump, drawing in gas, gas-fluid emulsions, and ultimately liquid, preventing gas lock. Even if gas returns later in the well's life, the pump will continue to operate effectively, regardless of the well's gas content.
