关键词: 精细控压钻井, 溢流检测, 气液两相流, 出口流量, 模拟计算

Abstract:

The current gas kick detection method cannot detect the trace of overflow，and thus we propose the overflow detection
methods for managed pressure drilling（MPD）and establish the wellbore overflow calculation model based on the gas-liquid
two-phase theory. A comparison of the simulation results with the measured date of MPD，reveals that it is difficult to detect
the overflow quickly and accurately；overflow can be detected by comparing the in flow and out flow to determine the type
of bottomhole complex trouble. If the out flow greater than the in flow，there may have overflow in the wellbore. When the
gas flows out from reservoir over 1 000 m of wellbore，there may be expansion in the wellbore，and the gas void and out flow
increase and the mud pit increases at the same time. But if the wellbore back pressure increase，the parameters increment may
decline. The flow out results simulated by the computer coincide with the results measured by the MPD. The overflow detection
by MPD can accurately find the kick，and the results of computer simulation is reliable in finding and controlling the overflow.

Key words: managed pressure drilling, gas kick detection, gas-liquid two-phase flow, out flow, simulation and calculation