Supplementary borehole drilling
AssigneeUnion Oil Company of California
InventorLeo I. Phelps
Life of this patent
Estimating the term…
Abstract
A duct assembly for drilling supplementary boreholes comprises a plurality of duct body sections, whipstocks, and separators forming multiple channel segments within the duct body sections. In one embodiment, the separators are plates that substantially divide each duct body section into two semicircular channel setments and align adjoining duct body sections, allowing the drilling of supplementary boreholes to be reliably directed without whipstock repositioning.
Claims23
A tool apparatus useful for drilling supplementary boreholes emanating from a pre-existing borehole extending to a previously-produced fluid reservoir, said apparatus comprising:
- a duct assembly comprising a plurality of joined duct sections, said duct assembly extending towards said fluid reservoir when said duct assembly is located within said well;
- a plurality of whipstocks attached to said duct assembly, wherein at least one of said whipstocks is proximate to said fluid reservoir when said duct assembly is located within said well;
- and
- a plurality of separators attached to at least two of said duct sections such that separators attached to adjoining duct sections are longitudinally spaced-apart, said separators form at least two channel segments for guiding a drill string within said channel segments towards one of said whipstocks.
An apparatus for drilling supplementary boreholes from an underground hole, said apparatus comprising:
- a duct string composed of duct sections extending from a near-surface location to a subsurface location when said duct string is located within said underground hole;
- a plurality of diverters for diverting a drill string radially outward from said underground hole, wherein said diverters are attached to said duct string;
- and
- a plurality of dividers attached to said duct sections such that dividers in adjoining duct sections are longitudinally spaced-apart, said dividers forming channel segments within said duct string, wherein at least one of said channel segments is capable of guiding said drill string towards one of said diverters.
A tool apparatus useful for drilling supplementary boreholes extending from a subsurface location within an underground well to a location within an underground formation, said apparatus comprising:
- a duct section, said duct section capable of being placed at said subsurface location within said well;
- a plurality of whipstocks attached to said duct section;
- a nose cone attached to one axial end of said duct section;
- and
- a duct separator attached to said duct section such that said duct separator and duct section form at least two channels for guiding a drilling assembly within said duct section wherein said duct separator is a substantially planar plate forming two substantially semicircular-shaped channels and wherein said duct separator does not extend over the entire length of said duct section.
A process for drilling a plurality of supplementary boreholes extending outward into a subterranean formation from a well, said process comprising:
- positioning a tool within said well, said tool comprising a plurality of joined duct sections forming a duct assembly, a plurality of diverters attached to said duct assembly, and a plurality of longitudinally spaced-apart channel guides attached to said adjoining duct sections forming a plurality of passageway segments extending within said duct assembly;
- running a drilling assembly through one of said passageway segments and one of said diverters;
- and
- drilling outwardly into said formation to form a first supplementary borehole.
A process for drilling a plurality of supplementary boreholes from an existing well into a subsurface formation which comprises:
- placing a whipstock string in said well wherein said whipstock string comprises a nose cone on one axial end of joined duct sections and a plurality of whipstocks wherein a separator is attached substantially within said duct sections such that said separators in adjoining duct sections are longitudinally spaced-apart;
- running a drill string though said whipstock string;
- and
- drilling a plurality of supplementary boreholes into said formation, each at different locations in said formation without substantially repositioning said whipstock string.
Dependencies are inferred from the claim text.