Patent ID: RE40067

Claim:
Apparatus for completing a multi-branch cased well for oil recovery by sequential cyclic steam injection methods and for petroleum production from non-uniformly-pressured heterogeneous reservoirs through medium curvature, liner-equipped, horizontal drainholes; said apparatus includes downhole equipment, tools and devices for making casing/liner and liner tubing sealed connections and individual liner/drainhole flow connections, comprising: a) a special steel casing joint equipped with a hard metal multi-channel whipstock permanently affixed to and sealed in said casing joint by means of an upper guide plate presenting at least two small feed-through vertical holes, one of which terminated at both ends by threaded connections, and two larger vertical holes, each leading to a slanted cylindrical curved channel partly filled with a cement plug and each said channel leading to an elliptical window machined in a direction slanted downwards at a pre-selected kick-off angle into the wall of said casing joint and plugged by a drillable plate conforming with the outer surface of said casing joint, b) a retrievable wedge-type top whipstock tool whose base presents at least two alignment pins or prongs fitting into said guide plate small holes, in which they are held by releasable latches, said top whipstock's outer lateral surface presenting at least one latching recess for its removal using an overshot tool, c) an overshot tool equipped with releasable hooks to pull out, re-orient and reset said top whipstock, in the same trip, d) a steel liner inserted in a drainhole drilled through each said whipstock channel, said liner hung with devices resisting liner weight and thermal expansion forces applied to said liner from above as well as from below and said liner permanently sealed into said channel by a pressure-sealing device including a heat-resistant seal, in addition to thermal cement, e) a tubing completion assembly conveying production fluids from a drainhole to the surface and steam from the surface to a drainhole; wherein said tubing completion assembly is terminated, at its lower end, by a heat-resistant, pressure-tight, multiple-breakable-sealed connecting device wherein two pairs of vertical tubular connector prongs, equipped with releasable high-temperature-sealing devices, respectively fit into the two larger holes and into the two smaller holes in the guide plate of said special casing joint, to respectively convey production fluids from a drainhole to said tubing assembly and steam from a known three-way valve to the other drainhole, f) a hydraulically-operated slot-cutting tool for selectively perforating said drainhole liner to establish a flow connection between a surrounding oil reservoir and said liner in its uncemented lower part.