Transient flow in continuous gas invasion wellbore under condition of circulation cease in liquid-based whole process underbalance drilling
The bore flow model of liquid-based process underbalance drilling includes the steady-state gas-liquid-solid multiphase flow of normal drilling and transient gas-liquid two-phase flow under conditions of circulation cease. For circulation cease open wells, the numerical simulation methods of characteristics parameters change of downhole transient gas-liquid two-phase flow with continuous gas invasion and mathematics to solve the model were developed. The gas-liquid two-phase flow characteristic parameters were calculated in the different size of the gas influx of underground. The results show that the larger gas volume leads to the faster movement velocity, the more knocking out drilling fluid and the larger bottom hole flowing pressure fluctuation. The exerting of wellhead back pressure can effectively control the underground gas expansion and the bottom hole pressure fluctuation.
drillingwhole process underbalancecirculation ceasegas invasiontransient flow
国家科技期刊平台
NSTL
万方数据
维普
