Abstract: A method and apparatus for multilateral completion comprises providing a casing string having a casing, a branching sub connected to the casing, and a locating profile. An expanding tool positionable in the branching sub is adapted to mate with the locating profile to fix a position of the expanding tool, such as to rotationally orient the expanding tool, fix a radial position of the expanding tool, and/or fix an axial position of the expanding tool. The branching sub has a non-expanded state, and the expanding tool is adapted to expand the branching sub.

Abstract: An oil well system for extracting oil extracted from a reservoir via a well, INCLUDES a separator device adapted to separate oil and water from a mixture extracted from a reservoir. The separator device has a non-vertical first flow path for the mixture and being arranged along a non-vertical portion of the well, a second flow path, separate from the first flow path, for receiving water or a water enriched phase that has been separated from the mixture by the separator device, and a plurality of drain openings along a section of the first flow path. The first and second flow paths are arranged such that water or the water enriched phase in the first flow path can flow by gravity to the second flow path via the drain openings. An opening area of the drain openings, per unit area of the first flow path, decreases in a flow direction of the mixture along the first flow path.

Abstract: The present invention provides methods for forming multiple wellbores from a single location. A relatively large diameter main wellbore is drilled to a known depth. A plurality of spaced apart wellbores are formed from the bottom of the main wellbore, wherein at least one such wellbore is a production wellbore for producing hydrocarbons from subsurface formations. Wellhead equipment for each production wellbore is installed at main wellbore bottom. Additional devices or equipment are also placed in the main wellbore, preferably near the bottom.

Abstract: An assembly for drilling at least one lateral well from a well bore having a longitudinally premilled window formed therein and having a first orientation key-way member formed in the premilled window and in communication with the premilled window and located on the down hole portion of the premilled window and having a second orientation key-way member formed in the premilled window and in communication with the premilled window and located on the up hole portion of the premilled window. The window is provided with a cover for closing the premilled window and first and second orientation key way members from fluid communication. A whip stock is provided for drilling at least one multilateral well. A key is provided which is spring loaded for being received into the premilled window and guided into locking engagement in the first orientation key way as the key is lowered down hole.

Abstract: A method and apparatus for forcing drainage devices through the sidewall of a borehole and into the formation to increase oil and gas recovery from the formation. The object usually comprises a plurality of drainage devices, which may be a plurality of nesting discs perforated to provide a passageway for recovery fluid. The discs and drainage device are forced non-drillingly through the side wall and into the formation. The apparatus and method also may be used with interconnected links instead of discs to push a core sampler into the formation and retrieve it. The housing includes a guide channel that is usually an angled passageway or tube. The discs or links are sized to be received in the guide. The apparatus includes a propulsion assembly that impacts the discs or links that act as an anvil assembly. Alternatively, the apparatus takes the form of a pre-loaded casing section, that is, a casing section in which a plurality of drainage devices have been incorporated.

Abstract: A well has a vertical casing with a window, and a lateral wellbore which communicates with the window, and which may have a casing or liner. A window assembly aligned with the window has respective passageways for first and second tubing strings, and has a concave surface for deflecting the first tubing string out into the lateral wellbore. The passageway for the second tubing string has a portion which is inclined at a very small angle with respect to a vertical centerline of the vertical casing. As the first tubing string is run into the vertical casing, a rotational locator is releasably coupled thereto by a soft release coupling mechanism. After the locator effects rotational orientation, the coupling mechanism is released and then permits the first tubing string to move therepast without damage. A seal assembly on the first tubing string is covered by a protective sleeve as it is inserted into the well, and exits the protective sleeve after entering the lateral wellbore.

Abstract: Apparatus and methods for completing a wellbore are disclosed. Certain ones of the apparatus and methods use a first packing assembly, a second packing assembly, and a pressurization assembly disposed between the first and second packing assemblies to plastically deform a liner in a radially outward direction via hydraulic pressure. Another method uses a liner having a first section and a second section, and a packing assembly. The first section is deformable in a radially outward direction at a lower pressure than the second section. The packing assembly is used to plastically deform the first section of the liner in a radially outward direction via hydraulic pressure.

Abstract: An apparatus and method for utilizing a flexible tubing string (18) for forming and isolating a lateral entrance opening (23) to a lateral bore hole (25) from a main bore hole (10). A packer (38) mounted on the lower end of a tubular guide (40) has an elbow (56) between an upper central entrance opening (58) and a side exit opening (60). The packer (38) and tubular guide (40) are lowered within the main bore hole (10) to a predetermined depth and azimuth for side exit opening (60) which is positioned adjacent the proposed lateral bore hole (25). Packer (38) is then inflated. The flexible tubing string (18) having a hole forming member on its lower end is lowered within tubular guide (40) and elbow (56) for forming the lateral entrance opening (23, 24) for the lateral bore hole (25) with opening (23, 24) isolated.

Abstract: Apparatus and corresponding methods are disclosed for controlling fluid flow within a subterranean well. In a described embodiment, a longitudinally spaced apart series of selectively set and unset inflatable packers is utilized to substantially isolate desired portions of a formation intersected by a well. Setting and unsetting of the packers may be accomplished by a variety of devices, some of which may be remotely controllable. Additionally, a series of fluid control devices may be alternated with the packers as part of a tubular string positioned within the well.

Abstract: An internal junction stabilizer is formed with an outer dimension less than the internal bore of a junction to be strengthened The stabilizer is inserted into the junction, and expanded into tight fit. Multiple stabilizers may be expanded one inside another to form a laminate for reinforcement in high pressure applications. Each layer of metal expanded to the next outermost section provides an additive effective on the mechanical properties of the junction. Expansion can be performed in a number of ways, including mechanical, hydraulic, explosive methods. Use of directional or selective swaging can be used to further effect a fit. Further embodiments of the invention include the use of sealing compounds, elastomers, and plastics to effect a hydraulic seal and fill gaps for strength purposes.

Abstract: A well casing junction connects an upper string of casing to a pair of lower or branch strings that diverge from each other. The junction tool has an upper section and a pair of branch sections that join the upper section and each other. The junction tool is collapsed for running into the well along with casing. To collapse, a force is applied to opposite sides to create identical, deep depressions in the opposite sides of the junction tool. Once in position, internal pressure forces the depressions outward to assume an expanded position. A support member locates at the junction and between the two branch sections. The support member reduces stress that occurs from moving from the collapsed to the expanded position.

Abstract: A pumping system comprises a pump barrel that is adapted to be placed into a well casing. A plunger is reciprocatably positioned within the pump barrel and has an open top end, a bottom end, and a traveling valve at the bottom end. A connector is coupled to the plunger below the top end. A rod is coupled to the connector and is translatable to reciprocate the plunger within the pump barrel using an upstroke and a downstroke. Further, the top end of the plunger is adapted to direct particulate into the plunger and away from the pump barrel upon each upstroke.

Abstract: A well completion system and associated methods of completing wells provides enhanced convenience in well completions involving well treatment operations. In a described embodiment, a single trip perforating and fracturing/gravel packing method permits a well completion assembly including a well screen and a perforating gun to be installed in a well, the well to be perforated and treated, and the perforating gun to be retrieved from the well in a single trip. Retrieval of the perforating gun permits multiple zone completions in the well without the perforating guns remaining in the well thereafter.

Abstract: Temporary no-go assemblies for use in locating a downhole tool at a predetermined target depth in a well are disclosed. Certain ones of the assemblies include a no-go sleeve for interfacing with a no-go shoulder in a casing and an actuating system for releasing the assembly from the no-go sleeve. Other ones of the assemblies include a key for engaging a landing nipple in a casing and a key retractor for retracting the key from the nipple. Still other ones of the assemblies include a key for engaging a no-go shoulder in a casing and a key retractor for retracting the key from the no-go shoulder. The assemblies are particularly useful in drilling and completing wells from a floating drilling rig.

Abstract: A formation isolation valve assembly for use in a well includes first and second fluid paths that are coupled to at least first and second completion zones. A first valve controls fluid flow from the first zone to the first fluid path, and a second valve controls fluid flow from a second zone to the second fluid path. The valves may include ball valves and sleeve valves.

Abstract: A method and apparatus for establishing connectivity of lateral branch liners to main well casings to achieve predictable and stable mechanical connectivity at the lateral junction of branch well bores to the main well bore to counter the problems of formation instability at the junction. After construction of a well having one or more lateral branches, a retrievable lateral branch template is located in the casing of a main well bore in positioned and oriented registry with a casing window that opens to a lined lateral branch. A retrievable lateral branch connector is then installed in assembly with the template to cooperatively define a production flow path having maximized mechanical integrity and optimized production flow in both the lateral bore and the main bore.

Abstract: A selective re-entry tool is provided that allows an operator at the earth's surface to perform intervention operations in one or more completion strings by allowing remote discrimination and orientation of a tool string to a target location in a single comingling completion string. The selective re-entry tool may broadly include a carrier body having a navigation port extending longitudinally therethrough, and an orienting key movably connected to the carrier body and releasably engageable with a discriminator groove in a tubing string to align the navigation port with a predetermined one of a plurality of branch tubings in the tubing string. The re-entry tool may further include a locking dog movably connected to the carrier body and releasably engageable with a locking recess in the tubing string to prevent rotation of the carrier body after the navigation port has been aligned with the predetermined one of the plurality of branch tubings.

Abstract: A subterranean well completion system and associated methods of servicing wells provide convenient access to selected ones of multiple tubing strings installed in wells. In a described embodiment, a completion system includes a wye block device which has an access control assembly separately conveyed into a housing assembly installed in a well. The access control assembly is conveyed into the housing assembly when it is desired to access a selected one of multiple tubing strings attached to the housing assembly.

Abstract: A downhole production well control system is provided for automatically controlling downhole tools in response to sensed selected downhole parameters. The production well having a production tubing string therein with multiple branches, i.e., zones. Communication and transmission of power (i.e. telemetry) over the production tubing string is by way of a combination of a hardwire system in the main borehole and a short hop system at the branches or laterals. Each zone includes a downhole control system and appropriate completion devices for controlling fluid flow. An acoustic or electromagnetic transceiver is associated with each control system for communication and/or transmission of power. An electrical conductor runs from the surface downhole along the production tubing string in the main borehole for communication and/or transmission of power, hardwired systems are well known.

Abstract: Multiple wellbores are interconnected utilizing a deflection device having a guide layer of lower hardness than the body of the deflection device, and a cutting tool having a guide portion and being operative to cut through the deflection device guide layer and a tubular structure lining a wellbore.

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.

Abstract: An artificial lift, concentric tubing production system for a well and method of using same. The system including an upper concentric tubing string portion comprising an inner production tubing string positioned within an outer production tubing string. A flow crossover assembly is connected to the upper concentric tubing string portion. The flow crossover assembly has first and second passageways. The inner production tubing string is in fluid communication with the first passageway and the outer production tubing string in fluid communication with the second passageway. An upper transducer is in fluid communication with one of the passageways of the flow crossover assembly and a lower apparatus is in fluid communication with the other of the passageways of the flow crossover assembly. The upper transducer may be a pump such as an electric submersible pump or a progressive cavity pump. The lower apparatus may be a pump, including an electric submersible pump, or a liquid/gas separator.

Abstract: A system adapted for controlling and/or monitoring a plurality of production wells from a remote location is provided. This system is capable of controlling and/or monitoring: (1) a plurality of zones in a single production well; (2) a plurality of zones/wells in a single location (e.g., a single platform); or (3) a plurality of zones/wells located at a plurality of locations (e.g., multiple platforms). The multizone and/or multiwell control system of this invention is composed of multiple downhole electronically controlled electromechanical devices and multiple computer based surface systems operated from multiple locations. Important functions for these systems include the ability to predict the future flow profile of multiple wells and to monitor and control the fluid or gas flow from either the formation into the wellbore, or from the wellbore to the surface.

Abstract: An assembly for use in a well containing a mixture of hydrocarbons and water wherein the assembly separates hydrocarbons or relatively lighter fluids from the mixture and injects water or relatively heavier fluids into the well. The assembly includes an upper pump that pumps the relatively lighter fluids to the surface. A tandem pump is positioned below the upper pump for pumping well fluids down to a downhole separator. An oil bypass tube is provided in communication with the tandem pump for transferring the relatively lighter fluids to the upper pump, for subsequent pumping to the surface. A recycle tube is also provided that communicates with the downhole separator and the tandem pump for transferring at least a portion of the relatively heavier fluids from the downhole separator to the tandem pump, for pumping the relatively heavier fluids back to the separator.

Abstract: A system and method that permits fluids, such as petroleum, to be pumped from two separate zones. A submergible pumping system, including a submergible electric motor driving a submergible pump, is deployed in a wellbore. The submergible pump intake is located in a first zone to intake a fluid. The fluid is discharged through a fluid-powered pump, such as a jet pump. The jet pump is coupled to a fluid intake disposed in a separate zone within the wellbore. The single system can be utilized to pump fluids from two different zones.

Abstract: An apparatus and method for directing a first and a second object into a primary and a secondary borehole respectively from a main borehole communicating therewith at a borehole junction. The apparatus includes a deflector for positioning at the borehole junction to direct the first and second objects into the primary and secondary boreholes. A retainer holds the objects relative to each other such that when the first object is aligned to be directed into the primary borehole, the second object is aligned to be directed into the secondary borehole. A retainer orienting mechanism orients the retainer relative to the borehole junction so that the objects are aligned to be directed into the boreholes. The method includes positioning the deflector at the borehole junction and inserting the objects and the retainer into the main borehole. The retainer is oriented relative to the borehole junction so that the objects are aligned to be directed into their respective boreholes.

Abstract: Apparatus and methods are provided for completing a wellbore junction. In one embodiment described herein, a lateral wellbore junction is sealed utilizing an apparatus assembled within the well. The apparatus may include multiple housings which are engaged with each other to form a sealed assembly with flow passages extending into the lateral wellbore, and upper and lower portions of a parent wellbore. Associated sealing devices and flexible couplings are also provided.

Abstract: An assembly, mountable below a whipstock, for engagement into an anchor packer is disclosed which has a valve member as a principal component. The assembly is stabbed into the anchor packer in a manner that isolates the main wellbore from the lateral to be created using the whipstock. An equalization feature facilitates the stabbing in of the assembly into the anchor packer. Upon concluding the stabbing in, the equalization opening closes and locks in the closed position. Thereafter, the lateral is created by milling a window (in the case of a cased wellbore) and drilling the lateral. Liners may be used within the lateral and are insertable by use of the whipstock. At any desired time when production is to resume from below the whipstock, the valve member is actuated while the anchor packer remains in position to hold the whipstock. The valve member can be actuated by mechanically shifting a sleeve or by dissolution with chemical attack of a dissolvable plug or by other techniques.

Abstract: Two or more opposing and outward facing profiles are fabricated and joined to each other along their outer edges, forming a section of a guide string. The sections of the guide string are secured together in an assembly and lowered into a single conductor. The assembly lands on the bottom of the well and may support its own weight. The guide string defines two separate longitudinal cavities or sections of the well. Each separate cavity allows drilling and installation of casing in the conductor.

Abstract: Apparatus and methods for completing a wellbore are disclosed. Certain ones of the apparatus and methods use a first packing assembly, a second packing assembly, and a pressurization assembly disposed between the first and second packing assemblies to plastically deform a liner in a radially outward direction via hydraulic pressure. Another method uses a liner having a first section and a second section, and a packing assembly. The first section is deformable in a radially outward direction at a lower pressure than the second section. The packing assembly is used to plastically deform the first section of the liner in a radially outward direction via hydraulic pressure.

Abstract: A milling guide assembly includes features permitting a milling guide to be accurately positioned within a subterranean well. In a described embodiment, a milling guide has a logging tool attached thereto and a wireline extending through the milling guide. When the milling guide has been positioned and anchored within the well, the wireline is detached from a weak point disposed between the milling guide and the logging tool. The wireline is then withdrawn from the milling guide.

Abstract: Methods and apparatus are provided for use in conjunction with subterranean well operations. In a described embodiment, an expandable wellbore connector is utilized in interconnecting multiple wellbores in the well. The wellbore connector is expanded into a cavity formed in one wellbore, and then another wellbore is drilled through the wellbore connector. The wellbore connector is sealingly engaged with tubular members in each wellbore.

Abstract: A dual completion method for oil/gas wells, which method is designed to prevent or at least minimize, coning of water in a hydrocarbon producing well. In a preferred embodiment the method includes the steps of perforating a common zone in the oil/gas well at vertically-spaced locations and producing water-free oil and/or other hydrocarbons through the upper perforations and the well annulus or tubing, as well as preferably hydrocarbon-free water from the bottom perforations through well tubing. Careful control of hydrocarbon and water production maintains a stable hydrocarbon and water contact in the production and prevents coning of the water into the hydrocarbon and in some cases prevents coning of the hydrocarbon into the water. Production of hydrocarbon and water in this manner facilitates an equal pressure drop acting near the hydrocarbon/water contact in the well and formation to keep the water from rising in the formation.

Abstract: A method of completing a subterranean well and associated apparatus therefor provide efficient operation and convenience in completions where production of fluids from a lateral wellbore and a parent wellbore is desired. In one disclosed embodiment, the invention provides a method of completing a subterranean well wherein a tubular member having an aperture formed through a sidewall portion thereof is inserted through a junction of multiple wellbore portions. The aperture is positioned so that it faces one of the wellbore portions. Apparatus provided by the present invention include various forms of flow diverters which may be utilized in the method.

Abstract: A method of forming and lining a branch borehole includes installing a packer in a main borehole, installing a whipstock on the packer, milling a window in the main borehole casing using the whipstock, recovering the whipstock, and then installing a deflector (20) to deflect a lining into the lateral. The external diameter (D) of the deflector is less than the internal diameter of the casing of the main borehole so as to permit subsequent milling away of cement and surplus lining material using a washover tool or thin-walled mill. The preferred deflector includes a relatively steep deflector face (21) at the upper end of the deflector and a relatively shallow deflector face (22) which connects the lower end (23) of the face (21) to the full diameter (D) of the deflector. If it is desired to use the maximum possible diameter casing for the lateral, portions of the formation and/or the main borehole casing are removed by an appropriate tool after the deflector (20) has been positioned within the borehole.

Abstract: A wellbore fluid recovery system for recovering fluid from a wellbore that has at least one lateral wellbore extending out therefrom. The system includes a first electric submergible pumping system for recovering fluids from a first zone of a wellbore, and a second electric submergible pumping system for recovering fluids from a second zone of the wellbore, such as from a lateral wellbore. Automated control mechanisms are used for independently regulating fluid flow from the first and the second electric submergible pumping systems. Such control mechanisms include automated downhole adjustable valves and variable speed electric motor controllers.

Abstract: The milling and whipstock assembly includes a whipstock having a ramp portion for directing the milling assembly to cut a secondary borehole in an existing cased borehole. The milling assembly includes a shaft having rigid and flexible portions and an under gauge cutting tool disposed on the lower end of the flexible portion and a full gauge cutting tool disposed on the rigid portion. A third under gauge cutting tool is disposed on the flexible portion in between the full gauge and under gauge cutting tools. In operation, the milling and whipstock assembly is lowered into the borehole and then the milling assembly is detached from the whipstock assembly. As weight is placed on the milling assembly, the ramp portion places a side load on the lower under gauge cutting tool causing the flexible portion of the shaft to flex and pivot allowing the under gauge cutting tool to come into engagement with the wall of the casing allowing the under gauge cutting tools to cut a window in the cased borehole.

Abstract: A remote-controlled tubing sleeve window for access to a lateral wellbore of a multilateral well. The tubing sleeve window has a tubular body portion that defines a side port that is sufficiently-sized to allow a well tool to pass. A sleeve is received in the tubing body portion such that it can reciprocate within the body portion. The sleeve is responsive to a remote command such that a side window defined in the sleeve can be substantially-aligned with the side port in an open relation such that a well tool can pass through said substantially-aligned side window and side port. A position sensor is also provided to sense a displacement of the sleeve with respect to the body portion.

Abstract: Apparatus and methods are provided which may be used in completing a wellbore junction. A lateral wellbore junction is sealed utilizing an apparatus assembled within the well. The apparatus may include multiple housings which are engaged with each other to form a sealed assembly with flow passages extending into the lateral wellbore, and upper and lower portions of a parent wellbore. Flexible couplings are provided which facilitate conveyance and positioning of the apparatus in the well.

Abstract: An apparatus and method for completing a junction between a primary and secondary wellbore. A deflector is located in the primary wellbore adjacent to the wellbore junction. The apparatus comprises a conduit comprising: an upper section; a lower section comprising a primary leg for engaging a seat of the deflector and a secondary leg for insertion in the secondary wellbore; and a deformable conduit junction located between the upper and lower sections whereby the conduit is separated into the legs; such that when the apparatus is lowered in the primary wellbore, the secondary leg is deflected into the secondary wellbore by the deflector such that the conduit junction becomes deformed, and the primary leg then engages the seat.

Abstract: Methods and apparatus are provided for separation of liquids of different densities in production fluid streams from underground wells. Methods and apparatus are also provided for separation of gas, oil and water in production fluids, transportation of the separated fluids to the surface, as well as reinjection of separated water from the production fluids into other formations. Other aspects include new separation arrangements which include gas or liquid driven motors, designs for multi-stage hydrocyclone separators and use of beam or rod pumps.

Abstract: A disclosed method and associated apparatus provide convenient and accurate control of rates of fluid flow within a subterranean well. In one described embodiment, an apparatus has multiple tubing strings installed within multiple wellbores intersecting formations or intervals into, or from which, fluid is to be flowed. A remotely controllable flow regulating device is provided for each of the formations or intervals to regulate the rate of fluid flow through its associated tubing string. In another described embodiment, a single tubing string is utilized with multiple remotely controllable flow regulating devices interconnected therein.

Abstract: A method for creating multiple branch wells from a parent well is disclosed. A multiple branching sub is provided for placement at a branching node of a well. Such sub includes a branching chamber and a plurality of branching outlet members. The outlet members during construction of the branching sub, have previously been distorted into oblong shapes so that all of the branching outlet members fit within an imaginary cylinder which is coaxial with and substantially the same radius as the branching chamber. After deployment of the branching sub via a parent casing in the well, a forming tool is lowered to the interior of the sub. The outlet members are extended outwardly by the forming tool and simultaneously formed into substantially round tubes. Next, each outlet member is plugged with cement, after which each branch well is drilled through a respective outlet member. If desired, each branch may be lined with casing and sealed to a branching outlet by means of a casing hanger.

Abstract: A method of completing a subterranean well and associated apparatus therefor provide efficient operation and convenience in completions where production of fluids from a lateral wellbore and a parent wellbore is desired. In one disclosed embodiment, the invention provides a method of completing a subterranean well wherein a device having multiple portals is positioned at a junction of multiple wellbore portions and engaged with other structures positioned in the well. Several alternate constructions of a device for use with the method are provided as well.

Abstract: A deflection apparatus is provided. In one described embodiment, the apparatus includes a torque resistant retrievable whipstock sealingly attached to a packer. The whipstock may be separated from the packer by applying an axial force to a first housing and thereby releasing a sleeve sealingly disposed between the first housing and a second housing for displacement relative to the second housing. The first housing and sleeve may then be removed from within the second housing, leaving a relatively large diameter seal bore attached above the packer.

Abstract: A lateral wellbore junction is formed by methods and apparatus described herein. In one described embodiment, an apparatus includes a section of casing and a sleeve axially reciprocably disposed relative to an opening formed through a sidewall of the casing. In one described method, the casing section is positioned within a parent wellbore, the sleeve is shifted to provide access through the opening, and a lateral wellbore is drilled by passing cutting tools through the opening.

Abstract: There is a provided an apparatus and process for multi-zone profile control in a well including a wellbore intersecting at least one production zone, at least one injection tube, at least one insulation means, and at least one zone isolation means. Control media is injected through the injection tube, exiting at at least one control media exit of the injection tube and entering the production zone. The insulation means allow multiple zones to be injected simultaneously with control media of different temperatures and pressures.

Abstract: Apparatus and methods are provided for achieving a lateral wellbore connection in a subterranean well. In one described embodiment, a deflection device is rotatably attached to one orienting member and conveyed into a cementing shoe positioned in a parent wellbore of the well, wherein the orienting member is engaged with another, complementarily shaped, orienting member. The deflection device is then rotated to face toward the lateral wellbore-to-be-drilled and a force is applied to the deflection device, thereby fixing its rotational orientation relative to the orienting members. Cutting tools are deflected off of the deflection device to cut outward through the cementing shoe to form the lateral wellbore.

Abstract: A method and system of drilling multiple radial wells using underbalanced drilling, by first drilling a principal wellbore; then providing a first carrier string having a deflection member on its lowermost end to a certain depth within the principal wellbore; orienting the deflection member into a predetermined direction; lowering a second drill string, such as coiled tubing or segmented drill pipe, down the bore of the carrier string, so that the drill bit on the end of the second string is deflected by the deflection member in the predetermined direction from the principal wellbore and a first multilateral well is drilled. When coiled tubing is used, fluid is pumped downhole through the annulus of the coiled tubing, and into an annular space between the coiled tubing and the carrier string so that it co-mingles with produced hydrocarbons; and the co-mingled fluids and any hydrocarbons are returned to the rig through the annular space between the borehole and the carrier string.

Abstract: Apparatus and methods are provided for completing a wellbore junction. In one embodiment described herein, a lateral wellbore junction is sealed utilizing an apparatus assembled within the well. The apparatus may include multiple housings which are engaged with each other to form a sealed assembly with flow passages extending into the lateral wellbore, and upper and lower portions of a parent wellbore. Associated sealing devices and flexible couplings are also provided.