物理法随钻防漏堵漏机理研究

物理法随钻防漏堵漏方法是利用专用井下工具将泵入的钻井液流量分流小部分，采用旋转射流直接作用于漏失井壁，配合合适的钻井液体系，使井壁滤饼形成的渗透率接近于零的随钻防漏堵漏技术。针对渗透性漏失及裂缝性漏失地层特点，以流体力学为基础，建立了基于物理法随钻防漏堵漏的物理模型，阐述了利用旋转射流的水力能量给漏失层井壁形成“人造井壁”随钻防漏堵漏的机理和方法。该方法不仅达到了随钻防漏堵漏的目的，还有效地扩大了钻井液密度安全窗口，有利于保护油气层。

MECHANISM STUDY ON PHYSICAL PLUGGING WHILE DRILLING

Physical plugging for lost circulation while drilling is to use a specialized downhole tool to divert as mall portion of the drilling fluid pumped downhole towards the lost circulation well bore in the form of a rotary jet to keep the permeability of the wellbore cake close to zero so long as the proper drilling fluid system is adopted. This study built up a physical model of this method based on the fluid dynamics according to the features of the formations having seepage loss or fracture loss, and then described the mechanism of using the hydraulic energy of the rotary jet to form an artificial wellbore at the loss spot. This paper recommends this method because it can not only realize physical plugging while drilling, but also effectively expand the safety window of drilling fluid density, very helpful for reservoir protection.