SINGLE TRIP WHIPSTOCK ASSEMBLY

摘要

A single trip whipstock assembly which can be run into a well, set, and operated from a window in the well casing in a single trip comprises a milling tool (5) attached to the upper end of a whipstock (6) to the lower end of which is attached a packer (7) or anchor which can be set by appropriate means prior to detachment of the mill from the whipstock to initiate window formation. The packer may be hydraulic and may be set by means of a setting tool (4) located above the mill (5) and connected to the packer by a hose (21). The mill (5) incorporates circulation ports which are initially isolated from the central chamber thereof to permit flow of hydraulic fluid from the setting tool to the hose (21) via the interior of the mill. Once setting has been effected, the hose (21) is severed permitting the piston of the setting tool to operate a flow diverter within the mill and open the circulation ports to the interior of the tool for subsequent drilling mud circulation during milling operation. The whipstock (6) includes a relatively steep ramp (32) at the upper end thereof so that initial breakthrough of the casing is effected predominantly using the side blades of the mill (5).