Patent Description:
The present invention is especially related to a module-based system consisting of portable modules with lifting and skidding mechanisms allowing high risk operations (material handling above live wells) for plug and abandonment operations on an offshore installation deck.

Hydrocarbon fluids are produced through a well penetrating into a subterranean formation, referred to as the reservoir. When the reservoir is emptied, the pressure falls in the reservoir, and the flow of hydrocarbon fluids to the surface is reduced. The well has at this point reached the end of its life and it must be permanently plugged and abandoned. Regulatory authorities, managing the petroleum activities, have requirements for how the well should be plugged and abandoned that the operator must adhere to.

Wells can also be temporary plugged before a new side track to the existing well is drilled. This is performed to tap into a different part of the reservoir and extend the life of the well.

The well consists of an outer conductor, overlapping casing strings, well head and production tubing. The production tubing is in the center of the well going from the reservoir to surface or seabed. The production tubing is used to transport the hydrocarbons up from the reservoir and to the surface.

The purpose of the plugging is to prevent leakage of hydrocarbon, formation fluids or well fluids to environment when the well is abandoned. The industry and regulatory authority standards demand two independent barrier i.e. - two cement plugs. The plug should be established as a rock-to-rock barrier.

In order to establish the rock-to-rock barrier, the casing and tubing must be removed to expose the rock. Several ways to perform this operation exists in todays marked; cut-and-pull, casing milling, section milling, etc. All these methods are using topside equipment and tools at the existing drilling rig or external rigs (installed at the same level as the main rig) to perform the necessary downhole operations.

The main object of the present invention is to provide a module-based system plug and abandonment operation of wells on an offshore installation partly or entirely solving the mentioned drawbacks of prior art solutions.

Further objects will appear from the following description, claims and attached drawings.

Module-based system for plug and abandonment operation of wells on an offshore installation according to the present invention is defined by the technical features of independent claim <NUM>. Preferable features of the system are described in the dependent claims.

The present invention provides a modular system for topside package for plug and abandonment operations.

The module-based system according to the present invention is adapted to be arranged on a deck below the main rig and skidding deck.

The module based system according to the present invention comprises modules needed for performing plug and abandonment operations.

Typical modules for performing plug and abandonment operations are:.

Accordingly, the by the present invention is provided a module-based system according to claim <NUM>.

According to one embodiment of the present invention the module-based system comprises a lift module that can hoist/lower modules or objects from deck level to correct height above deck.

In accordance with one embodiment of the module-based system according to the present invention it comprises a jack module comprising upper and lower jack segments that can be opened in two or more sections, moved in and out of well center and rotated, wherein an actuator for operation thereof extends though the lower segment jack segment so that the actuator protrudes below the lower jack segment.

According to one embodiment of the present invention the integrated material handlings modules are adapted for handling of blowout preventer, high pressure riser, wireline blowout preventer, wireline riser and topside completion equipment for a well.

In accordance with one embodiment of the module-based system it comprises hatches arranged to travel on dedicated rails in the frame module for opening or closing an opening in the deck and/or closing around objects extending through the opening in the deck.

According to one embodiment of the module-based system according to the present invention it comprises a transport trolley module arranged to travel on dedicated rails in the frame module for transport of objects to and from well center.

In accordance with one embodiment of the present invention the module-based system comprises a winch with redundant load paths, designed such that if one winch system fails the other shall remain intact and the load shall not drop.

According to one embodiment of the present invention the lift module is provided with an A-frame and winch that can be tilted in and out of well center, said A-frame and winchcan be used to run wireline as an integrated part of the module-based system.

In accordance with one embodiment of the module-based system it comprises a basket module adapted for storing pipes in a vertical position, said basket module is compatible with a pipe manipulator module for handling the vertical pipes in and out of well center.

According to a further embodiment of the present invention the module-based system comprises a cutter work deck module and/or tong work module.

In accordance with a further embodiment of the module-based system, the overall dimensions and weight of the respective modules is designed to make them suitable for use on fixed installations offshore.

According to a further embodiment of the present invention the module-based system, the modules are provided with quick connections used to connect energy to the modules.

In accordance with a further embodiment of the module-based system according to the present invention it comprises a common and central control system for all modules and functions so that said modules and functions are controlled by one system and with internal interlockings where needed.

Further preferable features and advantageous details of the present invention will appear from the following example description, claims and attached drawings.

The present invention is below described in further detail with references to the attached drawings, where:.

Reference is now made to <FIG> showing principle drawings of a module-based system <NUM> for plug and abandonment operation of wells on an offshore installation according to the present invention, seen from perspective, side, front and top views.

The module-based system <NUM> according to the present invention comprises modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> coupled to perform all plug and abandonment operations, enabling the module-based system <NUM> according to the present invention operate independent of main drilling tower <NUM> or external rigs.

According to one embodiment of the present invention the modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are provided with quick connections used to connect energy to the modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The module-based system <NUM> according to the present invention is installed on the same level as main rig <NUM> or on below decks on the offshore installation.

The module-based system <NUM> according to the present invention comprises modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> that enables the module-based system <NUM> to be built in situ without the need for external material handling devices, by comprises integrated modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM> for material handling. The module-based system <NUM> according to the present invention is thus self-assembling.

The system <NUM> according to the present invention comprises frame module <NUM> to be arranged on a desired deck <NUM> of the offshore installation, e.g. blow-out-preventer deck, wherein the frame module <NUM> is acting as a foundation for all other modules. The frame module <NUM> is according to the present invention provided with a telescopic extension to adjust the height of said frame module.

The module-based system <NUM> further comprises a lift module <NUM> (offshore installation and lift module) that is to be used both during installation of the module-based system <NUM>, as well as for hoisting/lowering modules or objects from deck level to correct height above deck, hereunder also adjustment of the height of the frame module <NUM>.

Reference is now made to <FIG> showing principle drawings of a second embodiment of the module-based system <NUM> according to the present invention, wherein the module-based system <NUM> further comprises a cutter work deck module <NUM>, and wherein the <FIG> show installation of the cutter work deck module <NUM>. In <FIG> is shown the cutter work deck module <NUM> placed on the deck <NUM> ready to be installed. In <FIG> is shown the cutter work deck module <NUM> hoisted using the lift module <NUM> to correct height in relation to the frame module <NUM> height. In <FIG> and <FIG> is shown the cutter work deck module <NUM> skidded in the horizontal plane, in a perpendicular direction of the length of the frame module <NUM> and into a desired position on a platform of the frame module <NUM>.

Reference is now made to <FIG> showing principle drawings of a third embodiment of the module-based system <NUM> according to the present invention, wherein the module-based system comprises a casing tong work deck <NUM>, and wherein the <FIG> show installation of the casing tong work deck module <NUM>. In <FIG> is shown the casing tong work deck module <NUM> placed on deck <NUM>, ready to be installed. In <FIG> is shown the casing tong work deck module <NUM> hoisted by using the lift module <NUM> to correct height in the frame module <NUM>. In <FIG> and <FIG> is shown the casing tong work deck module <NUM> skidded in horizontal plane, in a perpendicular direction to the length of the frame module <NUM> and into a desired position on a platform of the frame module <NUM>.

Reference is now made to <FIG> showing principle drawings of fourth embodiment of the module-based system <NUM> according to the present invention, wherein the module-based system <NUM> a pipe manipulator module <NUM>, wherein the <FIG> show installation of the pipe manipulator module <NUM>. In <FIG> is shown the pipe manipulator <NUM> module placed on deck <NUM>, ready to be installed. In <FIG> is shown the pipe manipulator module <NUM> hoisted by the lift module <NUM> to correct height in the frame module <NUM>. In <FIG> is shown the pipe manipulator module <NUM> transferred to rails on frame module <NUM> and moved into desired position in the frame module <NUM>, between the mentioned modules <NUM> and <NUM>, described above.

Reference is now made to <FIG> showing principle drawings of a fifth embodiment of the module-based system according to the present invention, wherein the module-based system <NUM> comprises a winch module <NUM>, e.g. a dual secured winch module, wherein the <FIG> show installation of the winch module <NUM>. In <FIG> the winch module <NUM> is placed on the deck <NUM>, ready to be installed. In <FIG> the winch module <NUM> is hoisted to correct height in the frame module <NUM> using the lift module <NUM>. In <FIG> the hoisted winch module <NUM> is skidded in the horizontal plane, in a perpendicular to the length of the frame module <NUM>, and moved into a desired position on a platform of the frame module <NUM>, which in the shown example is between the modules <NUM> and <NUM>.

Reference is now made to <FIG> showing principle drawings of a fifth embodiment of the module-based system <NUM> according the present invention, wherein the module-based system <NUM> comprises a basket module <NUM>, wherein the <FIG> show the installation of the basket module <NUM>. In <FIG> the basket module <NUM> is placed on the deck <NUM>, ready to be installed. In <FIG> is shown the basket module <NUM> hoisted using the lift module <NUM> to correct height in the frame module <NUM>.

Reference is now made to <FIG> showing a seventh embodiment of the module-based system <NUM> according to the present invention, wherein the module based system <NUM> comprises a jack module <NUM>, wherein the <FIG> show the installation of jack module <NUM>. In <FIG> the jack module <NUM> is placed on the deck <NUM>, ready to be installed. In <FIG> the jack module <NUM> is hoisted using the lift module <NUM> to correct height in the frame module <NUM>. In <FIG> the jack module <NUM> is skidded in the horizontal plane, in a perpendicular direction to the length of the frame module <NUM>, and moved into a desired position on a platform of the frame module <NUM>, which in the shown example is between the modules <NUM> and <NUM>, which in the shown example also is a position that is coinciding with well center. In <FIG> is shown a position where the jack module <NUM> is lowered onto a blow-out-preventer <NUM>.

Reference is now made to <FIG> showing a principle drawing where the module-based system <NUM> according to the present invention is installed on the blow-out-preventer deck <NUM> of an offshore installation, below the main drilling tower <NUM> of the offshore installation. The figure further shows lower risers <NUM> extending from a well head <NUM> and to the blow-out-preventer <NUM>, as well as Christmas three deck <NUM>.

Reference is now made to <FIG> showing principle drawings of further details of the module-based system <NUM> according to the present invention. According to the present invention the frame module <NUM> has three integrated rail levels for arrangement of hatch modules <NUM> and <NUM>, as wells as for a trolley module <NUM>. According to the present invention the module-based system <NUM> comprises a hatch module <NUM> movable on the mentioned dedicated rail, extending in longitudinal direction of the frame module <NUM>, wherein the hatch module <NUM> is movable between a closing position and an open position for opening and closing a hole in the deck <NUM> over the well center, respectively. In <FIG> is shown a situation where the hatch <NUM> is positioned in closing position wherein the hatch <NUM> closes the hole over the well center to make a barrier for dropped objects towards lower deck.

In <FIG> is shown a further embodiment of the module-based system <NUM> according to the present invention where it comprises a split hatch <NUM>, formed by two corresponding parts adapted to enclose circular objects when joined together. The respective parts of the split hatch <NUM> is arranged movable between a closing position and an open position over the hole in the deck <NUM> over the well center, wherein the respective parts of the split hatch <NUM> are arranged movable between open and closed position on dedicated rails, extending in longitudinal direction of the frame module <NUM>, wherein the respective parts of the split hatch <NUM> is arranged to move in opposite direction on the mentioned dedicated rails. By this is enabled a hatch <NUM> that in closed position will enclose circular objects extending into the well and in this manner make a barrier towards lower then when in close position. <FIG> shows the split hatch <NUM> in closed position, while <FIG> shows the split hatch <NUM> in open position so that objects may be handled through the opening in the deck <NUM>, e.g. objects from the Christmas three deck <NUM>.

According to a further embodiment of the module-based system <NUM> according to the present invention it comprises a transport trolley module <NUM> arranged to move in longitudinal direction of the frame module <NUM> on dedicate rails, as shown in <FIG>, <FIG> and <FIG>, wherein the transport trolley module <NUM> is movable between a position outside the mentioned platforms for modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and to a position over the mentioned hole in the deck <NUM> over the well center.

In <FIG> and <FIG> the transport trolley module <NUM> is positioned over the hole in the deck <NUM>, while in <FIG>, <FIG> and <FIG> the transport trolley module <NUM> is shown in the position outside the mentioned platforms.

Reference is now made to <FIG> showing details of the jack module <NUM> according to the present invention. The jack module <NUM> comprises a movable upper jack segment and a lower stationary jack segment <NUM> operable between a closed position and an open position. In <FIG> the jack module <NUM> is shown in a closed position.

In <FIG> the jack module <NUM> is shown in an open position, where the upper jack segment <NUM> and lower jack segment <NUM> is opened to allow large outer diameter objects to pass through the jack module <NUM>. In <FIG> is shown an example of use, where the jack module <NUM> is placed on top of a blow-out-preventer <NUM> with a tubing <NUM> going through the jack module <NUM> and blow-out-preventer <NUM>.

The module-based system <NUM> is installed by lifting the frame module <NUM><NUM> and lift module <NUM> over the well. This is performed using the material handling solutions on the offshore installation. It is positioned so that the center of the frame module <NUM> corresponds with well center. This is shown in <FIG>. All other modules can be installed using the lift module <NUM> and internal skidding mechanisms on the frame module <NUM>.

The work deck modules <NUM>, <NUM> come with a preinstalled tubing cutter and casing tong, to be used during plug and abandonment operations. The work deck module <NUM>, <NUM> is placed in the lift module <NUM> and lifted to the correct height, before they are skidded onto the frame module <NUM>. The skidding motion is first perpendicular to the length of the frame module <NUM>, to get the work deck module <NUM>, <NUM> out of the lift module <NUM>. The second skidding motion is parallel to the length of the frame module <NUM>, to position the module <NUM>, <NUM> in correct position. The lifting and skidding motion of the modules <NUM>, <NUM> is illustrated in <FIG>.

The winch module <NUM>, preferably in the form of a dual secured winch, can lift objects on the same deck level <NUM> as the frame module <NUM> or from the Christmas three deck below <NUM>. With the winch module <NUM> installed, the module-based system <NUM> has the capabilities to hoist or lower objects with redundant load paths, meaning that if one winch system fails the other shall remain intact and the load shall not drop. Using such redundant system allows lifting of objects over wells without shutting the stream of hydrocarbons down (shut-in). The dual secured winch module <NUM> is installed by loading it into the lift module <NUM>, hoist the lift module <NUM> to correct position and skid the winch module <NUM> out of the lift module <NUM> over well center. This is shown in <FIG>. It is removed by reversing these steps.

The jack module <NUM>, which is mounted to a skidding frame, is installed by loading it into the lift module <NUM>, hoist it to correct height and skidding it to well center, as shown in <FIG>. The jack module <NUM> is lowered onto the blow-out-preventer <NUM> by lowering the frame module <NUM>. Demount lower locking of cylinders and lower cylinders until upper flanges rests on lower part of jack. Upper jack segment <NUM> is now supported by four supporting steel bars. Unlock pin bolts for supporting steel bars and lower upper jack segment <NUM>. Unlock pin bolts in skidding frame and extend frame back in position.

The pipe manipulator module <NUM> is transported into the lift module <NUM> and lifted to correct height where it is skidded onto corresponding rails on work deck modules <NUM>, <NUM>.

Basket module <NUM> with pull string in vertical position is skidded into the lift module <NUM>. Basket module <NUM> is secured and lift is extended to upper position. See <FIG> and <FIG>.

The frame module <NUM> has three integrated rail levels for the mentioned hatches <NUM> and <NUM>, as well as the transport trolley module <NUM>. The trolley <NUM> and hatches <NUM>, <NUM> can travel along the dedicated rails, in and out of the frame module <NUM>, independent of each other.

The transport trolley module <NUM> is used to transport objects in and out of well centre. Typical objects transported on the transport trolley module are blow-out-preventer <NUM>, riser <NUM>, deck hatch, X-mas tree etc. See <FIG>. The transport trolley module has actuators that can adjust the position of the object by linear motion in three axis and rotation about the vertical axis.

The mentioned split hatch <NUM> is a set of two rectangular hatches, where each hatch has a semicircle slot, so that it can be closed around a riser section. See <FIG> and <FIG>. This creates a barrier for dropped objects towards deck Christmas three deck <NUM> below. The two split hatches <NUM> can travel in in and out of well center, where each hatch travels in opposite direction.

The auxiliary hatch <NUM> travels in and out of well center to close the open hole in the deck <NUM> when the permanent hatch that is present in the deck <NUM> is removed. This creates a barrier for dropped objects towards lower deck.

<FIG> is showing a complete module-based system <NUM> installed at the blow-out-preventer deck <NUM> at the offshore installation. Module-based system <NUM> is built up of several of the mentioned modules that together give the module-based system <NUM> the capabilities to plug and abandon (P&A) a well.

The jack module <NUM> can jack landing string or tubing up and down. Two slips segments in the jack <NUM> can grip on smooth tubing and actuators will move the upper jack segment <NUM> and landing string/tubing in the direction that is demanded by the operation.

The mentioned pipe manipulator module <NUM> can grip around pipe segments and transport them in/out of well center to/from the basket module <NUM>. The pipe manipulator module <NUM> is arranged to move linearly along three axes in the module-based system <NUM>.

The casing tong work deck module <NUM> has an integrated lifting device for a casing tong. The lifting device can move the casing tong in and out of well center, to make up or break out pipe joints.

The cutter work deck module <NUM> has an integrated movable frame for a tubing cutter. The cutter can move in and out of well center to cut the tubing into smaller segments when it is jacked up.

The lift module <NUM> has an integrated lifting device to handle objects, and to be used as foundation for wire line operation.

The usage of the module-based system <NUM> according to the present invention can be divided into different phases; well intervention, material handling of topside equipment, tubing retrieval, cementing, well abandonment.

In the well intervention phase the lifting module <NUM> is provided with an A-frame <NUM> used to perform wireline operations in the well separated from all other platform wireline systems.

Material handling of topside equipment uses the transport trolley module <NUM> and winch module <NUM> (dual secured winch) to lift the X-mas tree out from lower decks, lower risers <NUM> to the well head <NUM> and connect the blow-out-preventer <NUM> to the riser <NUM>.

The jack module <NUM> is used in the tubing retrieval phase to jack tubing up or lower landing string down. The jack module <NUM> has a lower stationary jack segment <NUM>, and upper movable jack segment <NUM> as shown in <FIG>. When moving the pipe vertically it is gripped in the upper jack segment <NUM> of the jack module <NUM>. The load can be transferred to the lower jack segment <NUM>, and a re-positioning of the upper jack segment <NUM> can be performed. The existing tubing <NUM> in the well can be jacked up, and the integrated cutting module <NUM> and pipe manipulator module <NUM> can cut the existing tubing into smaller sections and place it back into the basket module <NUM>. The process is repeated until a desired length of tubing is jacked up. The jack segments <NUM>, <NUM> can be opened for allowing large object to pass through as demonstrated in <FIG>. <FIG> is showing the jack module <NUM> installed on the blow-out-preventer <NUM> with the existing tubing <NUM> to be jacked up.

The module-based system <NUM> according to the present invention further comprises a common and central control system for all modules <NUM>, <NUM>,<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and functions so that said modules and functions are controlled by one system and with internal interlockings where needed.

Claim 1:
Module-based system (<NUM>) for material handling in connection with plug and abandonment operations of wells on an offshore installation,
wherein the module-based system (<NUM>) is adapted to operate independent of main drilling tower (<NUM>) or external rigs on the offshore installation by comprising modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>),
wherein the offshore installation comprises an upper main deck in the form of a main rig (<NUM>) and skidding deck and at least one lower deck (<NUM>-<NUM>) with limited available lifting height,
characterized in that
the module-based system (<NUM>) is adapted and installed at the lower deck (<NUM>) of the offshore installation by means of a frame module (<NUM>) acting as a foundation for all other modules (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), said frame module (<NUM>) having a telescopic extension to adjust the height of said frame module (<NUM>) to the available lifting height, and
wherein the module-based system (<NUM>) being configured to perform all material handling operations in connection with the plug and abandonment operations by comprising a lift module (<NUM>) and integrated material handling modules in the form of transport trolley module (<NUM>), pipe manipulator module (<NUM>), jack module (<NUM>) and winch module (<NUM>) interchangeable based on the operation to be performed