Abstract

The apparatus and method of the present invention facilitate the initiation of lateral bores from a main wellbore in a completed well having a packer and a tubing string. The preferred method involves setting a plug, which may be removed, through the tubing string, followed by a layer of sand, followed by a layer of cementitious material or other material that becomes hard. The cementitious material is drilled from the end of the production tubing by means of equipment passed through the length of the cementitious material. This allows running in with another packer or anchoring device to be located within the newly created bore in the cementitious material. The sidetracking device is secured to the anchoring device and oriented. The milling then proceeds with a high-efficiency milling tool that creates a window through the cementitious material and outer casing. A milling assembly can then be used to complete the window and begin the lateral bore. If subsequent bottom production is required, the cementitious material can be underreamed down to the sand. The sand can then be washed from the initial plug that was set to support the cementitious material in the original wellbore. Multiple laterals can be accomplished in this manner by repeating the process steps.