Abstract: A one trip whipstock system includes both a one trip combination mill and associated whipstock. The one trip combination mill comprises an upper cutter and lower cutter below the upper cutter. The upper cutter and lower cutter are joined by a cone that widens towards the upper cutter. In operation, a whipstock is connected to the drilling sub by shear bolts. A guide lug on the whipstock faces the drilling sub between the lower cutter and upper cutter for riding on the cone when the drilling sub is advanced along the whipstock. Preferably the shear bolts connect to the lower cutter. Also, the lower cutter has smaller gauge than the upper cutter, to such an extent that the relative gauge sizes of the lower cutter and upper cutter permit the upper cutter to exit casing during drilling before the lower cutter exits casing. Further, there may be provided a watermelon mill and a string mill above the upper cutter and the watermelon mill, string mill and the upper cutter preferably have the same gauge.

Abstract: A downhole retrieving tool, in which a tubular member has a tubing string connector end and a conical retrieving dish on the tubular member spaced from and opening towards the tubing string connector end. Stabilizers are spaced around the tubular member at the tubing string connector end. A retrievable whipstock comprises a concave, with a recess formed in the concave between upper and lower conical walls. The upper side wall intersects the face of the concave to form an anchor point. A method for retrieving a downhole tool, such as a whipstock, in a well, in which a retrieving tool having a retrieving dish is lowered into a well, inserted into the recess to engage an anchor point, and removed from the well. Fluid may be injected through circumferentially spaced fluid passageways communicating with the bore of the tubular member to remove unwanted material from the recess.