Wellbore milling and drilling

Abstract

Wellbore operations (e.g. for milling and/or drilling) are disclosed which require a reduced number of tool trips into a wellbore to create a cut-out pocket, opening, or window in a tubular such as casing in the wellbore; and, in some aspects, to continue into a formation adjacent a main wellbore forming a lateral wellbore in communication with the main wellbore. Preferably one trip is required to complete a window or a window and the lateral wellbore. In one aspect a full gauge tool body is used so that the completed lateral wellbore is of a substantially uniform diameter along its entire length, which, in one aspect is suitable for the passage therethrough of full gauge tools, pipe, devices, and apparatuses. In one aspect a cutting system has cutting apparatus initially covered with a wearable away material which is worn away by contacting a tubular to be milled, exposing the cutting apparatus for milling and/or for drilling formation adjacent the wellbore. In certain aspects the lateral wellbore is: about one foot long; two feet long or less; five feet long or less; between five feet and fifty feet long; one hundred feet long or less; between about one hundred and about two hundred feet long; or two hundred or more feet long. In one aspect mill-drill tools are disclosed that both mill tubulars and drill formation.

Dependencies are inferred from the claim text.