Abstract: An offshore well system has an assembly for tensioning an inner riser or casing string. The system has a hanger which lands on an internal load shoulder. The hanger has a gripping mechanism on its lower end which engages a mandrel, the mandrel being connected to tieback casing. The gripping mechanism allows upward moving of the mandrel relative to the hanger, but not downward movement. A running tool releasably engages an interior portion of the mandrel. A launch adapter secures to an upper end of the hanger. The launch adapter slidingly engages a running string which also extends upward through a blowout preventor. Closing the blowout preventor and applying pressure to the launch adapter causes it to move downward, pushing the hanger onto the load shoulder. Subsequently, the running tool is pulled upward to apply tension to the casing which is held by the griping mechanism. The running tool is retrieved along with the launch adapter.

Abstract: The invention relates to a well casing 11 including at least two casing lengths 12, 13, 14, 15, 16 with a first casing section 12 having and outside diameter OD12 and an inside diameter ID12 being fitted and cemented in position extending downwardly from the top of the well. The remaining sections are installed subsequently each subsequent casing section 13, 14, 15, 16 having an outside diameter OD13, OD14, OD15, OD16 and an inside diameter ID13, ID14, ID15, ID16 and the diametrical difference D1, D2, D3, D4, D5 between the outside diameter OD13, OD14, OD15, OD16 of the sections 13, 14, 15, 16 being less that the internal diameter ID12, ID13, ID14, ID15 of the corresponding fitted sections 12, 13, 14, 15 being an amount which is just sufficient for the subsequent sections 13, 14, 15, 16 to pass down through the internal bore of the corresponding fitted section 12, 13, 14, 15.

Abstract: The subject of the present invention is an oil well production string hanger. A well comprises a production string, or tubing, through which the hydrocarbons flow, and a casing which supports the wall of the well. Between the two, there is an annular space used for control of the well. The tubing hanger fixed at the top of the well generally has two passages allowing communication with the tubing and with the annular space respectively. The invention relates to a tubing hanger with a single passage which gives access both to the tubing and to the annular space and allows the annular space to be plugged using a simple, economical, reliable and reversible method.

Abstract: An adjustable casing hanger for suspending a casing string from a wellhead is provided which includes an elongated tubular body having a lower end adapted to be connected to the casing string and an upper end portion including a plurality of axial annular grooves formed in the outer diameter surface thereof, each groove defining a downwardly facing support surface, and a support ring adapted to be positioned around the body in one of the grooves, the support ring having an upwardly facing load shoulder for engaging the support surface and a downwardly facing load surface for engaging a support shoulder formed in the wellhead, whereby the elevation of the casing hanger within the wellhead can be adjusted depending on in which groove the support ring is positioned.

Abstract: An adjustable casing hanger comprising a first tubular component having an end connection attachable to the upper end of a casing string in use; a second tubular component securable to the first component, the relative axial position in which the first component is secured to the second component being adjustable to vary the vertical position at which the casing string is supported; and a load shoulder radically movable between an expanded position in which in use it supports the second component on a co-operating landing surface and a contracted position in which it allows passage of the shoulder past the landing surface.

Abstract: A single tubular member, or monobore riser, is provided for tubing hanging operations via a drilling riser and BOP, where wireline and/or coiled tubing deployed tools may be directed into production and annulus bores via a dual bore safety package and a dual bore selector and where various circulation modes may be established in cooperation with the choke and kill conduits in the BOP stack or with a length of tubing through the monobore riser in cooperation with selectively operable valves in the production and annulus bores of the safety package, a retainer valve in a single bore at the top of the dual bore selector, and by means of BOP rams capable of closing about a spool of the safety package and with a side outlet in the safety package. For Xmas Tree (XT) operations, the identical monobore riser is provided for surface communication to a dual bore selector and dual bore Riser Safety Package (RSP) secured to the top of the XT.

Abstract: The invention relates to a filter which is useable in conjunction with subsea hydraulic control circuits. The filters incorporated in a housing which can be stabbed in or out of a control unit to become part of one or more fluid control circuits. The stab-type housing can be inserted with a remotely operated vehicle. Other configurations involve long, slender housings for use with subsurface safety valve control lines as well as with tubing hanger housings. The slender design allows mounting right on the production tubing. A rupture disc feature is available so that if excessive pressure differential is obtained due to clogging, the filter unit within the housing can be bypassed to allow continuing operation.

Abstract: A tensioning system for a tieback string of casing between a subsea wellhead and a surface wellhead employs hydraulic pressure. A mandrel is connected into the tieback string. A casing hanger mounts to the mandrel and an internal gripping member between the casing hanger and the mandrel allows upward movement of the mandrel relative to the casing hanger but prevents downward movement. The operator lowers the string into the well with the casing hanger in an extended upward position and secures the tieback. The operator then closes the blowout preventer and applies hydraulic pressure in the annulus below the blowout preventer. Seals seal the casing hanger to the surface wellhead and also seal the inner diameter of the casing hanger to the running conduit. The hydraulic pressure forces the casing hanger down onto an internal landing shoulder in the surface wellhead.

Abstract: A subsea choke assembly for a well has a resilient closure seal within it which is used for retrieval purposes as well. The closure member is a metal resilient ring having tapered seal surfaces. The tapered seal surfaces locate between the choke body housing and the choke body bonnet. When securing the bonnet to the housing, the resiliency of the closure seal must be overcome, as well as the force required to insert an inner seal into its sealing surface within the bore. When the bonnet is released, the closure seal has sufficient spring force to push itself upward from the housing. In addition, it pushes the bonnet upward from closure seal. The choke body moves upward in unison with the bonnet, freeing the inner seal from its sealing surface.

Abstract: A well support structure for supporting a casing string from an offshore production platform includes a clamp sized to surround an upper portion of the sidewall of the outer casing or conductor, with the clamp mounted to a carriage to enable the clamp to be moved in at least two transverse directions to position the clamp adjacent the upper end of the string to provide the sole support for the casing string when the carriage and clamp are securing in position relative to the platform.

Abstract: A casing tensioning system applies tension to a string of casing between a subsea wellhead and a surface wellhead. The tensioning system has an outer hanger with a load ring and a ratchet ring that engage a mandrel. The mandrel is connected into the string of casing. The outer hanger has a disengaged position and an engaged position. When running, the outer hanger lands on a load shoulder in the surface wellhead while the casing hanger is in the disengaged position. The operator subsequently lowers the casing and latches the casing to the subsea wellhead. The operator then removes the casing running tool. The operator sets an annulus seal using a seal running tool. The annulus seal actuates a release member to cause the ratchet ring to move to the collapsed engaged position. After the seal is set the operator pulls tension on the casing.

Abstract: An adjustable mandrel hanger system is employed for maintaining tension in a string of casing extending between a subsea wellhead assembly and a surface wellhead housing. The system has a mandrel which connects into the string. A locking member locks to the exterior of the mandrel. The locking member has a cocked position which allows both upward and downward movement of the mandrel relative to the locking member. The locking member has a weight supporting position which will prevent downward movement of the mandrel but allows upward movement of the mandrel relative to the locking member. The locking member lands on an internal shoulder in the surface wellhead housing while the string is being lowered into the well. The running tool has an actuating member which will hold the locking member in the cocked position and in engagement with the internal shoulder while the running tool secures the lower end of the casing string into engagement with the subsea wellhead assembly.

Abstract: A hanger suspension system includes an inner casing hanger having an outer circumferential surface with at least three sets of at least three longitudinally spaced outwardly projecting load bearing members azimuthally spaced about the outer circumferential surface and separated by linear flow passages. A hanger assembly is positioned on each set of bearing members and is axially slidable on the outer circumferential surface of the hanger. Each hanger assembly includes a plurality of longitudinally spaced arcuate members having inwardly extending load bearing shoulders for engaging the load bearing members of the inner hanger. The hanger suspension system also includes an outer head having a non-restrictive bore with annular recesses which include load bearing surfaces and camming surfaces.

Abstract: An independent screwed wellhead apparatus and method provide for connecting a high pressure casing nipple (34) to internal threads (36) disposed along the bore (38) of the wellhead body (12) to temporarily increase the working pressure capability of the wellhead body (12). The internal threads (36) are supported by a thick wall (44) of the wellhead body (12) disposed in a lower end (13) of the wellhead body (12). The lower end (13) of the wellhead body (12) has a higher working pressure capability than the upper end (19) of the wellhead body (12). The high pressure casing nipple (34) temporarily isolates the upper end (19) from the higher pressure.

Abstract: A string of tubular members is suspended in tension from a surface wellhead by suspending the string from a hanger within a bore in the wellhead; supposing a support member on the wellhead; moving the support member into engagement with the hanger; inserting at least one support shoulder on the support member into an annular recess in the hanger; and supporting the tubular members in tension from the support member.

Abstract: A tubing hanging set for hanging, locking and sealing a submarine oil well includes a tubing hanger which is seated on an upper internal surface of a connection sleeve which in turn is seated on an internal surface of a casing hanger. The tubing hanger is provided with passageways extending therethrough and tubular extensions are connected in the passageways and to tubing passing through a double hydraulic packer. The lower end of one of the tubes passing through the packer extends into a oil producing zone and the other tube passing through the packer is in communication with an annular chamber between the other tubing and the casing. An installation tool is also provided which can be detachably connected to the tubing hanger for carrying out a method of installation of the tubing hanging set in a wellhead housing.

Abstract: A method of installing a wellhead component such as a tubing hanger or tree cap utilizes hydraulic pressure to move the component downward. A blowout preventer is connected to the production tree. The component has a primary metal seal and an elastomeric installation seal. The component is lowered on drill pipe through the blowout preventer into the tree bore with the installation seal sealingly engaging the bore. The primary seal is in a run-in position prior to setting. The operator closes the blowout preventer and pumps liquid through a kill line into the annular chamber below the blowout preventer. This causes the component to move downward, deforming the primary seal into the sealing engagement with the bore and the component.

Abstract: A method of tensioning casing between a subsea well and a surface wellhead employs an adjustment sub. The adjustment sub has upper and lower portions connected together by a threaded section. The running tool locates within the adjacent sub and is employed to secure the lower end of the casing to a tieback latch within the subsea housing. Continued rotation shears out a lower portion of the running tool, causing the threaded section to rotate relative to at least one of the other portions. Rotation of the threaded section brings a hanger on the upper sub portion downward into engagement with a load shoulder in the surface housing.

Abstract: A running tool for setting a casing hanger seal in a subsea well utilizes annulus hydraulic pressure. The running tool has a mandrel which carries a body. A setting sleeve is mounted to the mandrel for movement with the mandrel. An energizing ring secures to the setting sleeve and carries the casing hanger seal. A bulk elastomeric seal is carried by the setting sleeve. The bulk seal seals in the bore of the wellhead housing, enabling hydraulic pressure to be applied for driving the setting sleeve downward to set the casing hanger seal. A safety device prevents the bulk seal from sealing against the bore unless the casing hanger seal has already moved to its desired position in the pocket between the casing hanger and the bore of the wellhead housing.

Abstract: A tieback system for a subsea well employs a tieback member that can be utilized in the event tieback threads in the casing hanger become damaged. An annular groove is formed in the bore of the wellhead housing above the casing hanger. The tieback member connects to tieback conduit and has a lower end that slides into the interior of the casing hanger. A locking device will lock the tieback member to the groove in the wellhead housing. The locking device includes a retainer which carries a radially movable locking members that are cammed outward by downward movement of the tieback member relative to the retainer.

Abstract: A wear bushing assembly for a subsea well to protect a casing hanger during drilling latches by use of a collet. The wear bushing includes a tubular member which lands on the upper end of the casing hanger. A metal collet secures to the wear bushing. The collet has slots in it so as to allow it to radially deflect. The collet has an external shoulder which snaps into and latches in a profile formed in the casing hanger. The collet may serve as a protective portion of the wear bushing.

Abstract: A metal-to-metal sealing method and apparatus for use on oil and/or gas wells, utilizes an upper seal member and a lower seal member, wherein the energizing of the seal members is staged to cause the lower seal member to become sealingly engaged. before the upper seal member becomes sealingly engaged. The seal members may have two seals of different construction; one seal is an interference type seal, and the other seal is a wedge type seal.

Abstract: A well assembly utilizes a casing tensioning system that allows a preselected amount of stretch to be applied in the casing. The assembly includes a tubular mandrel that secures to the upper end of the string of casing. A load ring has internal grooves that mate with exterior grooves on the mandrel, the load ring being of a ratcheting type. A retainer will latch the load ring in the wellhead housing. A positioning ring mounts to an upper portion of the mandrel to position the load ring at a desired distance above a stop shoulder on the lower portion of the mandrel and the load ring. During tensioning, the load ring remains stationary in the wellhead housing as the mandrel is pulled upward until the stop shoulder contacts the load ring.

Abstract: There is disclosed subsea well equipment in Which an inner wellhead housing is lowered into and landed in the bore of an outer wellhead housing in order to install an inner casing string suspended from the inner housing within an outer casing string to which the outer housing is connected. The inner housing is locked down in the bore of the outer housing by a locking part on the inner housing which is forced into a locking recess in the bore in order to preload the connection between the housings. An assembly releasably connectable to the inner housing is provided for lowering the inner housing in the landed position and then locking it down within the bore of the housing in response to manipulation of a pipe string from which the assembly is suspended.

Abstract: An adjustable mandrel hanger assembly will maintain tension in a section of casing extending from a subsea location to a surface wellhead. The assembly has a mandrel that secures to the upper end of the casing. The mandrel has grooves on its exterior. A collet slides over the mandrel and has grooves on its interior for mating with the grooves on the mandrel. The collet has inclined load flanks on its exterior. A load ring lands on a load shoulder provided in the surface wellhead housing. The load ring has load flanks on its interior that engage the load flanks of the collet. A retaining ring locks the load ring in the wellhead housing. A running tool pushes downward on the load ring while tension is maintained on the mandrel. The collet ratchets over the mandrel grooves.

Abstract: A running tool for running casing in a subsea well has a full bore. The running tool is run on casing which will be of the same inner diameter as the diameter of the well casing. The running tool has a body and a movable seal sleeve. The seal sleeve carries a casing hanger seal. After cementing, manipulation of the casing causes the seal sleeve to move downward to a lower position to set the seal.

Abstract: A subsea well assembly has a tubular inner housing that locates within a tubular outer housing. A locking element carried by the inner member is biased outward for engaging a groove provided in the bore of the outer member. The inner member has a metal compression shoulder that has a skirt portion that engages the rim of the outer member. A recess located in the load ring provides slight resiliency to the skirt portion of the load ring. This resiliency allows the load ring to deflect elastically during bending forces exerted on the inner member. The slight deflection of the skirt portion of the load ring results in the locking element moving deeper into the groove to preload the connection.

Abstract: An improved subsea tubing hanger having a body with an external shoulder for landing on a seat within a subsea wellhead housing, locking ring carried on the hanger to engage an interior recess of the wellhead housing with an actuator ring for setting the locking ring. A preloading mechanism includes a biconical radially movable split ring hydraulically actuated by an axially movable conical ring cooperates with the locking ring to prevent any movement of the tubing hanger when engaged.

Abstract: A running tool for a subsea well utilizes a hydraulic circuit that will amplify tension pulled on drill pipe to perform various functions. The running tool has a pump cylinder which will pump hydraulic fluid once the running tool is latched into the wall assembly. The fluid is pumped out by upward movement of the drill pipe to a first function cylinder. The first function cylinder applies pressure to the well assembly to perform the first function. The operator pulls until a selected tension has been reached. Then the operator will slack off. At that moment, a pilot controlled control valve will shift to a second mode. In the second mode, continued pulling of tension on the drill pipe will supply hydraulic fluid to a second function cylinder.

Abstract: An all-metal, well annulus packoff assembly for establishing a high pressure, corrosion resistant metal-to-metal seal between a wellhead housing and a casing hanger, including an annular metallic seal element having a generally upstanding U-shaped cross section that is adapted for non-rotational sequential setting against the hanger and the housing.

Abstract: A mudline tubing hanger is disclosed in which the tubing hanger is provided as an integral part of the tubing string and is set within the casing by an hydraulic setting mechanism driven through an external control line and actuated by a wireline shifted sleeve. Further manipulation of the sleeve isolates the setting mechanism from the tubing and external control line, establishing a chemical injection conduit with access to the tubing bore through the external control line.

Abstract: A well tool locates within a subsea wellhead to seal and isolate the wellhead from testing of blowout preventer stack located on a riser string extending from the wellhead to a surface vessel. The well tool has a mandrel and a body which are axially moveable relative to each other. The body has a locking element which can move from a radially retracted position outward to engage grooves in the wellhead. The body also has an elastomeric seal for sealing the interior of the wellhead. A wedge ring has a compression member mounted to it for energizing the seal. Simultaneously, the wedge ring pushes the dogs outward. The wedge ring moves downward with the mandrel. A retaining assembly will retain the mandrel in the upper position until it is desired to set the tool. The retainer releases the mandrel for moving downward by rotating less than one turn. The wedging surfaces can be moved to a disengaging position to disengage the wedging surfaces from actuating the locking element.

Abstract: A tieback connector for a subsea well assembly has provisions to enable testing of a tieback seal without having to set any isolation seals in casing below the upper tieback member. The tieback connector has a lower tieback member with an upward facing receptacle. The lower tieback member has a set of running grooves spaced from a set of tieback grooves. An upper tieback member is lowered into the receptacle. The upper tieback member has tieback grooves that engage the tieback grooves of the lower tieback member. A lower seal on the upper tieback member engages a lower sealing area located below at least one of the sets of running grooves and tieback grooves. An upper seal located on the upper tieback member engages an upper sealing area located above at least one of the sets of the running grooves and tieback grooves. A test passage extends between the upper and lower seals. An isolation test tool is positioned in the upper tieback member, with isolation seals above and below the test passage.

Abstract: The casing suspension system includes a hanger having a load transfer mechanism and a finding/latching mechanism for finding, latching, and transferring load to an outer casing. The load transfer mechanism includes a ring disposed within a reduced diameter portion around the hanger. The ring includes a plurality of load bearing elements extending downwardly with the load bearing elements having a plurality of external teeth. The load bearing elements include an upwardly facing convex annular shoulder which engages a mating downwardly facing concave annular shoulder on the hanger. A spring retainer is disposed around the lower end of the load bearing elements to bias the load bearing elements inwardly. The hanger also includes a spring tube disposed below the load transfer ring. The spring tube includes a plurality of integral gates having keys. As the hanger is lowered into the well, the spring retainer maintains the load bearing elements in the "in" position.

Abstract: A running tool for lowering, landing and setting a well structure, such as casing hanger and a packoff has an elongated tubular body in which are mounted a plurality of locking dogs that releasably lock a casing hanger to the tool, a plurality of packoff running pins for releasably locking a packoff to the tool, and a plurality of packoff retrieval pins to engage a packoff in a wellhead housing and secure it to the tool for retrieval from the housing. The locking dogs are cammed radially from the tool body into their hanger engaging position by an actuator sleeve, and the running pins and retrieval pins are spring-biased in a radial direction towards their packoff engaging positions and releasably held in their retracted positions by retraction shafts in the tool body.

Abstract: A subsea well has tieback facilities for further sidetrack drilling. The well has an inner string casing hanger with an outer hanger portion and an inner hanger portion. The inner and outer hanger portions are latched together at the surface and lowered simultaneously. The inner casing string secures to the inner hanger portion. The tieback assembly includes an intermediate tieback conduit that extends into the bore of the outer hanger portion. An inner tieback conduit extend into the bore of the inner hanger portion. For later sidetrack drilling, the inner tieback conduit is pulled upward to unlatch the inner hanger portion from the outer hanger portion, retrieving the inner casing through the intermediate tieback conduit.

Abstract: A hydraulic casing hanger and packoff installation tool includes a central tubular member with a drill pipe upper connection and an annular chamber at the lower end thereof with a pair of concentric axially movable pistons mounted therein. A plurality of fluid passages are positioned in the wall of the tubular member and extend from the piston annular chamber to the middle portion of the tubular member where it exits. The pistons have a lower tubular extension which carries releasable latching mechanism which connects the tool to the packoff to be installed and transmits the axial force of the pistons to the packoff. A drill pipe stinger extends through the annular chamber with a releasable latch mechanism mounted on an enlarged lower portion. The releasable latching mechanism connects the tool to the casing hanger for lowering the casing and hanger into the well bore.

Abstract: A retrievable guide base and gimbal unit for a subsea well, and a tool for use with a pipe running to retrieve the guide base and gimbal from the subsea wellhead.

Abstract: A well tool assembly for running a casing hanger and a packoff into a wellhead housing during a single trip into the well, comprising a tubular inner mandrel, a locking mandrel, an outer annular body surrounding and rotatably connected to the inner mandrel, an outer sleeve surrounding the outer body, and means to prevent relative rotation between the outer body and the locking mandrel.

Abstract: A running tool will set a packoff between a casing hanger and a wellhead housing utilizing weight and hydraulic pressure. The running tool has a mandrel which connects to the drill string. A lower and an upper body are carried by the mandrel. The lower body releasably connects to the casing hanger for supporting the casing hanger as it is lowered into the well. The packoff mounts to the upper body. An elastomeric seal locates on the upper body of the packoff. The upper body will move downward relative to the lower body once the casing has been cemented. In this lower position, weight of the drill string transmits from a collar to the elastomeric seal to form a seal against the wellhead housing. Hydraulic pressure may then be applied. The hydraulic pressure creates a force on the upper body to set the packoff. The running tool along with the elastomeric seal will be retrieved to the surface.

Abstract: There is disclosed apparatus for use in suspending an inner case within an outer casing of an offshore well at the ocean floor, which includes an outer body adapted to be connected to the outer casing for lowering therewith into a landed position at the ocean floor, a hanger body adapted to be connected to the inner casing for lowering therewith into the bore of the outer hanger body, and first and second circumferentially split rings carried about the hanger body for radial movement with respect thereto between contracted and expanded positions in which they may be moved with the hanger body into and out of the bore and normally expanded expansion in which they are seated within the bore of the outer body to support the hanger body from the outer body.

Abstract: A wear bushing for a casing hanger mounts to the bore of a casing hanger before the casing hanger is lowered into the well. The running tool for running the casing connects to the wear bushing. The wear bushing has a setting ring that connects to the seal for the casing hanger. The running tool has a setting sleeve that connects to the setting ring. The running tool will release from the wear bushing and the setting ring after the casing has been cemented and the seal set.

Abstract: The invention relates to a method and apparatus suitable for example in enabling the installation of a casing hanger within a bore in an oil-drilling wellhead in a manner so that the installation and the sealing-in of the casing hanger is accomplished in a single operation. The invention thus comprises installing a component (2) within a bore (4) so as to be received therewithin in a fluid-type manner utilizing expandible seals (8) and a shoulder (36) within the bore (4) adapted to be contacted by a leading edge (32) of one of two concentrically arranged sleeve members (12, 14) which are driven downwardly within the bore towards the shoulder, the two sleeve members which encircle the component (2) being secured together by shearable links (25).

Abstract: There is disclosed an offshore well installation wherein a shoulder of a casing hanger body supported within a casing head on a platform at the water surface has been lowered onto a seat in the head so as to support a casing string anchored at its lower end to a mudline hanger in tension, the lower end of the hanger body being connected to the upper end of the string by an adjustable sub which is manpulated by a tool lowered through the hanger body and into the sub so as to adjust it from an extended position in which its shoulder is above the seat in the head to a retracted position in which the shoulder is seated on the head and the casing string is placed in tension.

Abstract: A tieback system for a subsea well utilizes a tieback connector. The tieback connector has a body that lands on a wellhead housing located on a sea floor. A funnel extends downward from the body for sliding over the wellhead housing. A lockdown sub is carried by the body and has a set of tapered threads on its exterior. A lock ring is carried by the lockdown sub. The lock ring has an exterior profile for engaging an internal groove formed in the wellhead housing. Rotating the lockdown sub moves it downward from a recessed position to a locking position. In that position, the rotation causes makeup to the threads and causes the lock ring profile to tightly engage the groove in the wellhead housing.

Abstract: An improved subsea tubing hanger having a body with an external shoulder for landing on a seat within a subsea wellhead housing, locking means carried by the hanger to engage the housing to lock the hanger in landed position, which locking means includes a locking element, actuator for setting the locking element and a securing pin for holding the actuating means in its locked position but being releasable responsive to sufficient upward force to sever the securing pin. The improved running tool includes a body with hydraulic actuated latching means for engaging the tubing hanger and which maintains its engagement with the tubing hanger even when hydraulic pressure is lost. The actuator includes an area exposed to hydrostatic riser pressure with sufficient area to retain the actuator in latched position even through the remainder of the actuating means is exposed to well bore hydrostatic head urging it out of latched position.

Abstract: An underwater sub-surface safety valve block is connected between a well head located at the sea bottom, and the lower end of a riser. This allows the production tube and/or the service tube of the completion string to be closed by means of gate valves. This sub-surface safety valve block comprises a valve body provided with a vertical through-bore tightly closed at its upper end by a packer to which the upper portion of the completion string is connected. The bottom is tightly closed by a tubing hanger to which the lower portion of the completion string is connected. The packer and the tubing hanger are fastened inside the through-bore by means of a mechanical hooking which can be disengaged by means of a hydraulic controlled action. They are each provided with a through-channel in order to connect the respective production tubes with the central region of the through-bore, which can be closed by means of a gate valve.

Abstract: A subsea well completion system having an improved tubing hanger that includes passageways through the hanger to one or more of the tubing annulus, the casing annulus and seals. The passageways may include vertically extending seal bores which are normally closed by check valves which may be operated to the open position. A tree adapter is connected to the tubing hanger and includes passageways coacting with the hanger passageways and includes externally connected side ports. The check valves may be selectively and remotely controlled externally of the completion system for monitoring the various annulus. The system may be abandoned by pumping cement through the passageways to seal them off and thereafter severing the completion system without the aid of a drilling rig.

Abstract: An improved wellhead casing hanger for suspension of successive casing strings with particularly small annular spacings having an adapter sleeve of double wall construction which is utilized with a load bearing shoulder on the inside of the inner member for receiving a conventional expanding type hanger, with the annulus between the inner and outer walls providing an improved fluid return path without restricting the bore of the sleeve, packoff for sealing the annulus at the appropriate time and an installation tool.

Abstract: A tool for setting the packoff between the casing hanger and the wellhead utilizes differential area pistons. The tool has a mandrel which connects to a string of drill pipe. The mandrel carries a body and is axially movable relative to the body. A setting sleeves is carried by the body for connection to the packoff. A setting sleeve piston is carried by the body for relative movement relative to the body. A mandrel piston is carried by the mandrel for movement with the mandrel. Passages in the body communicate the mandrel piston with a setting sleeve piston and contain an incompressible fluid. Axial movement of the mandrel causes the pressure to increase to drive the setting sleeve piston downward to set the packoff.