| 摘要 |
The whipstock assembly comprises an assembly casing (9) with preformed windo ws connected to production casing (7), a landing tube (21) is located within assembly casing (9) for re ceiving whipstock shaft, a key is located within tube (21) for cooperation with J-slot on whipstock shaft. The whipsto ck consists of upper (49) and lower (55) portion which are fixed against relative rotation by splines. The assem bly casing (9) with landing tube (21) is positioned in the borehole using a gyro survey tool for correct orientation of the windows. After a first side hole has been drilled, upper portion (49) is raised and rotated to place wedge su rface (51) for drilling a second side hole. Tube (21) is initially closed by a cap containing a marking fluid; after the cap has been drilled out the marking fluid indicates the removal of the cap. In a second embodiment two vertically spac ed side holes are drilled. |
