The choke manifold is a key device for controlling well surges and implementing pressure control in oil and gas drilling, and it plays an important role in ensuring drilling safety.
The core function of the throttling manifold lies in maintaining the bottom hole pressure by controlling fluid discharge. When overflow or well surge occurs underground, the blowout preventer assembly needs to be closed to seal the wellhead. At this point, the throttle manifold releases the fluid (drilling fluid, gas, etc.) in the well through the precise opening and closing of the throttle valve on it (usually available in manual adjustable, hydraulic and fixed types), thereby controlling the casing pressure (casing pressure).
The fundamental purpose is to maintain the bottom hole pressure slightly higher than the formation pressure all the time, prevent the formation fluid from continuing to flow into the well, and create conditions for subsequent well drilling operations.
The working process of the choke manifold can be summarized as follows: The fluid enters the manifold from the side outlet of the wellhead four-way, first passing through the open gate valve, and then reaching the choke valve. By adjusting the opening degree of the choke valve, the cross-sectional area of the flow path can be changed.
According to the principles of fluid mechanics, when high-pressure fluid flows through these narrow channels, the flow velocity will increase, but the pressure will significantly decrease, thereby achieving the goal of precisely controlling pressure and flow. Ultimately, the throttled fluid is guided to the drilling fluid gas separator or led to a safe area through the blowout pipeline.
Second, when the pressure inside the well is too high, blowout operations are carried out. By directly opening the dedicated blowout valve to release a large amount of water, the safety of the blowout preventer group at the wellhead and the drilling platform is protected.
A complete throttling manifold system is typically composed of a throttling valve (the core control component), a flat valve (used to open or cut off the flow path), pipelines, pipe fittings, a pressure gauge (used to monitor riser pressure, casing pressure and valve opening degree), and a hydraulic control system, etc
Its installation has strict requirements. For instance, it should be installed on both sides of the four ways at the wellhead, and the blowout pipeline should be connected to the downwind direction of the well site and at least 30 meters away from the wellhead, etc.
In conclusion, the throttling manifold is like a "precision regulating valve" for pressure control in oil and gas Wells. Through the core mechanism of throttling and pressure relief, it plays an irreplaceable role in balancing formation pressure, preventing blowout from running out of control, and ensuring operational safety.