In most cases, unbalanced drilling equipment can be used to control the pressure of the drilling. But the control pressure drilling equipment required for the separation processing capacity is small, other equipments are more complex. Controlled pressure drilling is not required due to the secondary flow in pipelines used balanced drilling, the reserve tank and geological sampling equipment. However, the control pressure drilling need to increase closed loop drilling system, dynamic annulus pressure control system, continuous circulation system, equivalent circulating density reduction tools, lifting pumps and other special tools, to accurately control bottomhole pressure.
Rotating control device (RCH) can be used for unbalanced drilling operations, it is also one of the main pressure control equipments, it is the key supporting devices for these with pressure closed loop system and dynamic annular pressure control system. Low rotation control device is the most common design of gas drilling, high-pressure rotating control device is the most common design for unbalanced drilling and drilling control equipments. Well, mission pump is also a necessary part of the industry areas which plays a different role with drilling equipment.
Managed pressure drilling’s most critical system is pressure closed loop system, including rotating control head, high-pressure choke manifold, drill string check valve, sampling equipment, drilling fluid / gas separation equipment, storage tanks, drilling fluid pump and ignition devices. The key equipment of the system is from the rotating control device out of the flow lines, choke manifold, sampling systems, four-phase separator, relief lines and burning towers, produced fluid storage tanks, storage tanks and drilling fluid pump drilling, in which four separator is the core unit.
The four separator working principle is that drilling fluid goes into one of the four separation chambers. Solid particles set in the chamber, settling at the bottom of separator, through the screw pump out or stop drilling then to treat. The separated gas through the gas flow valves to control exhaust gas, oil level through oil level controller regulate oil flow valve to control. Then the drilling fluid goes into two separate rooms for oil stratifying, the upper layer is oil, , the lower layer is drilling fluid. Oil is discharged to storage tanks, drilling fluid is discharged into three separated rooms, water level controller regulate water valve to control excretion, all separation chamber gas are discharged through the gas control valve. In the actual operation process, the closed loop system by adjusting the mud pump emission and control annulus back out throttle.
Under the situation that almost does not change the drilling fluid density, you can effectively control the well bore pressure. When connected to the single, manual, semi-automatic or fully automatic throttling device can be applied back pressure to the wellhead, to ensure the successful completion of the job. After drilling fluid through the four-phase separator separation process, the slurry is pumped into circulation tank, and has normal circulation.