自动防斜钻井钻具设计

目前所使用的各种钻具主要是靠钻具本身的重力来产生降斜力，在井斜角很小时，降斜力一般很小，在某些区块钻井时不能满足防斜要求。据此，设计了一种自动防斜钻井钻具，该工具包括钻铤体、偏心套筒、钢球、活塞及螺栓等。偏心套筒通过钢球挂在钻铤体外表面上，该偏心套筒一端部的内壁上有一环槽，并且该端部上位于薄边处还沿轴向延伸出一个凸台，该凸台内有一与有环槽贯通的两端封闭的弧形半环槽。在钻铤体上，与环槽对应处有与该钻铤体内腔贯通的通孔，与半环槽对应处有导流孔，该导流孔通过流道与钻铤体上的活塞腔相连通。在活塞腔内有一活塞。该钻具根据不倒翁原理和千斤顶原理，能够自动利用液压力量来产生降斜力，从而防止了井眼的偏斜。

Design of a Drilling Tool for Vertical Drilling Automatically

As for the currently- used drilling tools, the drop-off hole angle force is produced mainly by the gravity of the tools, When the deviation angle is very small, general1y the drop-off force is very small too, and this can not meet the need of deviation control during the drilling in some blocks. There for a Drilling Tool for hole-deviation control Automatically is designed. It is composed of collar, eccentric tube, steel-balls, piston and bolt, etc. The eccentric tube hitches on the surface of collar through the steel-balls. There is a looped slot in the interior surface of the eccentric tube, there is a protruding section located on the thin side along the axial of the eccentric tube, there is a semi-circle slot in the interior surface of the protruding section which is connected with the looped slot. Corresponding with the looped slot there is a through hole in the collar connected with the inside of the collar; Corresponding with the semi-circle slot there is a guiding hole in the collar. There is a piston cavity in the collar which bottom is connected with the guiding hole through the channel inside the collar. There is a piston inside the piston cavity. Based on the principle of tumbler and principle of jack, the tool can use the hydraulic pressure to produce drop-off hole angle force which can prevent the hole from deviation.