直井气侵后气液两相参数分布数值模拟

Numerical Simulation for Gas-liquid Two-phase Flow Parameters Distribution in Vertical Well after Kicking

钻井过程中发生气侵后,由于压力、温度、偏差因子等参数变化影响,气体沿井眼滑脱上升的同时会伴有一定膨胀,而加剧井底压差,导致气侵量不断加大直至井喷。气侵直至井喷过程中井筒内为瞬态气液两相流动,研究气侵后井底气液两相参数发展变化规律及井底压力变化特征对认识井喷发生发展规律有重要的指导意义。以甲烷-钻井液为循环介质,在接近井底实际工况情况下对气侵发生直至井喷过程进行了数值模拟,模拟计算了不同气侵量下气侵不同阶段的流型变化规律、井底压力变化规律、速度分布,并取得了初步认识。

When gas kick Occurs during drilling, because of pressure,temperature,coefficient of gas compressibility and other parameters changing continuously,gas will slip along the borehole and also accompany expansion some extent,and bottom hole differential pressure increases,resulting in the amount of invasion gas increasing continuously until blowout. The procedure of gas kick till blowout in the borehole is transient gas-liquid two-phase flow,studying on the development of gas-liquid two-phase flow parameters variation characteristics and bottom hole pressure variation characteristics plays an significant role to understand blowout occurrence and development characteristics. Methane-mud is used as the circulating medium simulates the procedure of gas kick till blowout near the bottom under the condition which is almost the onsite drilling process. Analyzing the flow pattern,bottom hole pressure variation characteristics,and velocity distribution under the different stages of gas kick,different influx, and obtained an initial understanding.