Improved method for drilling multi-lateral wells with reduced under-reaming and related device

摘要

An improved method for drilling a lateral well from an existing wellbore is disclosed whereby a section of said existing wellbore is preferably enlarged such as by under-reaming. The enlarged section is filled with a material such as, for example, epoxy which hardens to form an impermeable body. The hardened material is drilled out laterally and also longitudinally, such that a sealed junction is formed within the impermeable body between the lateral well and existing well. The longitudinal drilling follows an arcuate path. In one embodiment of the present invention, a packer positioned within the enlarged section may be filled with the pumped material to thereby avoid any contamination of the material with other downhole elements such as mud and oil whereby the composition of the pumped material is consistent and known. In one embodiment, an arcuate drillable guide may be positioned in the enlarged section prior to filling the enlarged section with material. The arcuate drillable guide thereby subsequently guides a drill bit through the hardened material along an arcuate path for reconnecting the existing wellbore through the enlarged section.