WHIPSTOCK OF DRILLING TOOL FOR CUTTING-OUT WINDOWS IN WELL CASING STRING Russian patent published in 2003 - IPC

FIELD: cutting-out of windows in well casing strings for cased well sidetracking in drilling, for instance, inclined and horizontal wellbores from parent wells during well drilling and servicing. SUBSTANCE: whipstock has deflecting unit with whipstock proper having spoon-shaped chute and bracing unit with slip holder having wedge guide with protrusion and slip engaged with recess. Both units are interconnected by connecting unit. The latter is made in form of longitudinal channel in body of deflecting tool from its lower end at angle of 0.1 to 2.0 deg. To longitudinal axis of deflecting tool with which upper end of slip holder is engaged. Connecting unit has through radial channel into which wedge lock is introduced. Chute is made on slip external surface over its entire length. This chute is similar to chute of whipstock. Lower end of slip holder has shoulder through which case is brought onto slip holder. Case length exceeds length of slip holder. Case upper part has side window for slip, for its radial motion. Slope wedge guide of slip holder is narrowing downward. Longitudinal channel in whipstock body and engageable with it upper end of slip holder may be made cylindrical or of some other shape. Radial through channel in connecting unit may be made, for instance, cylindrical, and wedge lock installed into it may be made correspondingly in form of cylindrical rod split longitudinally over inclined plane into two halves. Made in shoulder of slip holder, from its lower end, is hollow and through radial channels into which inside spring-loaded locking pins are introduced for which through radial holes are made in case. Higher reliability of deflecting tool fastening in casing string and more efficient bracing effect arc attained. Window cutting0out in casing string is made strictly at preset angle irrespective of thickness of casing string wall. Sidetracking is more effective. During transportation of whipstock, its length may be reduced. EFFECT: provided convenience in whipstock operation. 5 cl, 7 dwg