Abstract: Multi-lateral wells include one or more connections between a larger diameter well casing and liner-equipped branch-wells of smaller diameter initiated with a small angle deviation from the casing axis, so as to facilitate the sequential insertion of the directional drilling string and of the liner string, used respectively for drilling and for completing each lateral branch. Each such insertion requires, in the casing string, an elliptical window cutout presenting a vertical axis of more than ten feet and a horizontal axis of only a few inches, corresponding to the diameter of the branch-well.

Abstract: Single horizontal wells drilled through heterogeneous reservoirs are capable of greater oil productivity than vertical wells, often with lower produced GOR and WOR. Multiple drainholes tied-in to a vertical cased well are even more beneficial. Completion of such drainholes in many sandy reservoirs must use cemented liners. Well configurations comprising multiple drainholes liners, each of them tied-in to a vertical casing by pressure-tight connections require novel technologies making use of some novel downhole equipment, tools and procedures for drilling, tie-in and completion of such wells. These may be for newly-drilled wells or may be obtained by re-entry into an existing vertical cased well. Specific equipment, including novel casing joints, whipstocks, intermediate liners and tubing completion assembly components applicable to new wells are described herein.

Abstract: Low-cost, medium-curvature, deviated drainholes are drilled from a vertical cased well in soft formations, using the jet-drilling technique with a coiled-tubing. The high-velocity liquid jet is oriented at a small angle from the axis of the coiled tubing in the selected direction. The jet nozzle assembly is held by a pin in a reference groove in the tubing wall, parallel to its axis. A similar pin in a conventional sonde containing orientation sensors is also inserted in the same groove, so that the jet's spatial orientation is fully determined, with respect to the vertical and North. The jet angle with respect to the tubing axis is pre-set by mechanical or hydraulic locking devices and periodically re-adjusted, based on the sonde's spatial orientation data.

Abstract: A Downhole catalytic Methanator reactor assembly is hung within the cemented casing of a vertical well for the purpose of producing large volumes of high quality steam and oil soluble gases for injection into horizontal drainholes drilled into a deep Heavy Oil reservoir, in order to make the Heavy Oil more mobile. Steam is generated in part by the heat of chemical reactions taking place within the reactor assembly. The exothermic Methanation reaction takes place within a fixed bed of catalyst particles, at a temperature below 800.degree. F., when a Syngas feed (H2,CO and/or CO2) comes in contact with a catalyst. Boiler feed water supplied to the reactor assembly from the surface is vaporized in boiler-type water tubes immersed in the catalytic bed, or by direct contact with the catalyst and with the hot gas phase flowing through the bed. The Syngas feed may be supplied to the reactor from the surface, or made directly by Partial Oxidation of Natural Gas in Oxygen within the downhole assembly.

Abstract: Heavy oil is recovered from deep reservoirs by injection of a gaseous mixture containing hydrogen, steam and in some cases oil soluble gases and/or vapors. This mixture is produced by a reversible exothermic catalytic reaction in a down-hole reactor and injected into a well drilled, preferably horizontally, into the reservoir. The reactor feed streams are prepared in surface facilities with low air pollution, using as feedstocks water, air and inexpensive fuels, such as natural gas, coke or residual fuel oil.The heavy oil contacted by the injected gaseous mixture is formed into a mobile oil bank of reduced viscosity, which is produced to the surface by means of production wells or by alternatively using the injection well in a production mode. The process is of particular interest for reservoirs deeper than 1,000 feet, located in the vicinity of natural gas fields, oil refineries or coal mines.