井喷关井水击压力计算及可靠性分析

Calculation and Reliability Analysis of the Shut-in Water Hammer Pressure in Case of Blowout

钻井过程中,发生了溢流或井喷,应立即关井。关井过程中,防喷器需经受关井产生的水击压力作用。该文对井喷喷流为天然气、钻井液和气液两相混合物三种情况下的关井水击压力进行分析计算,并以此进行了关井可靠性分析。分析认为,仅在井喷喷流为钻井液且喷流速度较大时,关井方式应选择“软关井”,以降低关井水击压力,其他情况应选择“硬关井”,以减少地层流体侵入。

In case of overflow or blowout during drilling,the well should be shut down immediately.During the shut-in process,the BOP needs to withstand the shut-in water hammer pressure.This paper analyzes and calculates the shut-in water hammer pressure when the blowout jet is natural gas,drilling fluid and gas-liquid two-phase mixture.Based on this,the shut-in reliability analysis is performed.According to the analysis,only when the blowout jet is drilling fluid and the jet velocity is large,"Soft Shut-in"should be selected to reduce the shut-in water hammer pressure.In other cases,"Hard Shut-in"should be selected to reduce formation fluid intrusion.