| 摘要 |
A system for separation of fluids and drill cuttings received from a borehole during an under-balanced drilling procedure. The system is designed to cope with significantly varied pressures and flow rates, particularly in relation to gas content of drill fluids returned to the surface during the drilling process in a production zone, and to provide effective separation and to reduce the detrimental effect due to the presence of the drill cuttings in the returned drill fluids. In the present invention there is utilized a first stage, high pressure vessel in which a major portion of the gases ad drill cuttings are separated, and a second stage, horizontal low pressure vessel, preferably of greater volume than the high pressure vessel, in which further separating is achieved, including the separate removal of the drilling liquid to be returned to the drill tube. Because in under-balance drilling, the most serious variation in the pressure of the returning fluid is due to rapid increases in the proportion of gases in the drill fluid, the system of the present invention includes features allowing the control of the operating pressure in the high pressure vessel by way of the flow control of the gases exiting the high pressure vessel while the remaining separating procedure continues to provide effective results.
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