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在常规井眼中，钻柱在充有钻井液的井筒内运动时会引起波动压力，破坏井眼系统压力平衡，导致井喷，井漏和井塌或卡钻等吉下复杂情况和事故，在小井眼中，由于水力学系统各流道组合发生了改变，预测和控制小井眼波压力就显得尤为重要，文章结合小井眼钻井实例，定量分析了有关因素对小井眼波动压力的影响，提出了在小井眼起钻中，严格控制起下钻速度的重要性。

AN ANALYSIS OF THE FACTORS INFLUENCING SURGE PRESSURE IN A SLIM HILE

Surge pressure will be aroused in a conventional borehole,when a drilling string is moving in the well bore filled with drilling fluid,by which the pressure equalization in the borehole system will be destroyed,thus causing the complicated downhole circumstances and accidents as well blowout,lost circulation and well slough or drill pipe sticking,etc.Owing to the fact that various flow path assemblages in hydraulic system have been changed in a slim hole,it is even more important to predict and control the surge pressure in the slim hole.In combination with an example of drilling slim hole,the influence of relevant factors on the surge pressure in the slim hole is quantitatively analyzed and the importance to strictly controlling the velocity of round trip in the slim hole is proposed in the paper.