Patent Description:
A deployment of an electrical submersible pump in an oil or water well is common practice. Additionally, the use of an associated bypass-system is well known. The bypass system was designed to allow access to a well below an electrical submersible pump assembly in order that logging and/or well intervention operation could be performed without the removal of the completion, thus enabling work to be carried out under dynamic well conditions. Continual development of the system has maximized the operational benefits and includes permanent downhole monitoring of the well parameter and electrical submersible pump performance using a multi sensor system.

Bypass systems are available for an extensive range of casing weights and can be supplied to suit all well environments, using a wide range of materials to suit individual well chemistry and being internally coated to provide added protection and reduce friction as required. Each bypass system is individually designed to provide the optimum completion, affording full protection to the electrical submersible pump power cable and auxiliary service lines whilst providing uninterrupted access to the well below the electrical submersible pump.

Bypass-systems usually comprise a Y-Tool. The Y-Tool provides the facility by which the electrical submersible pump assembly is deployed with bypass tubing to allow access to the well in order that logging and/or intervention work may be carried out below without retrieval of the completion. The Y-Tool provides a single connection to the production string above and has a bypass connection below directly in line with the production string to allow the passage of logging tools to the well below via the bypass Tubing. The Y-tool comprises a fluid tubing and a further fluid tubing in which the electrical submersible pump is arranged.

A further connection at the base of the Y-Tool allows the electrical submersible pump assembly to be suspended. The Y-Tool has a groove on either side to allow the passage of the electrical submersible pump power cable, or other auxiliary service lines. These umbilicals are secured in the Y-Tool groove with clips thus ensuring full protection during deployment. The internal profile of the Y-Tool is designed to ensure a smooth flow path from electrical submersible pump discharge to production tubing.

Bypass-systems are designed and built to suit specific well completion. A well completion can be for example a cleanout logging operation and/or a means of running downhole samplers below the electrical submersible pump on horizontal reservoir sections. For performing such operations a coiled tubing logging plug is used.

The coiled tubing logging plug can be deployed in all standard bypass systems and is used as a means of sealing between the fluid tubing, in particular a tubing nipple bore, and the coiled tubing outside diameter. The plug can be used for various combinations of coiled tubing strings and tubing nipple sizes. It is utilized successfully for clean out operations, production logging runs and also as a means of running downhole samplers below the electrical submersible pumps on horizontal reservoir sections.

The plug is attached to the coiled tubing string via a retaining sleeve and collets, the latter being activated to a release position on engagement of the tubing nipple profile.

On release of the retaining sleeve from the holding collets the plug is automatically locked in the nipple profile. The plug cannot be released prior to engagement in the nipple. Once locked in place the plug can only be released or unseated if the retaining sleeve or sleeve is pulled into the plug from below and pin is sheared and/or a bottom crossover shoulders the bottom edge of the collet lock on the coiled tubing plug. This aligns up the collet locking fingers with the groove in the sleeve allowing them to collapse and to unseat. Only if the tool string is pulled into the plug it will be unseated.

When cleanout/logging operations are complete the electrical submersible pump is switched off, and after a short period to allow equalization across the pump, the tool string is pulled out of the hole. As the tool string with retaining sleeve or sleeve or crossover engages the bottom of the plug, a pin is sheared and/or the bottom crossover shoulders the bottom edge of the collet lock on the coiled tubing plug and in turn allows the locking mechanism to collapse and the plug to be retrieved to surface along with the tool string.

If the coiled tubing logging plug cannot be removed from the fluid tubing of the bypass system, it is not possible to continue with the fluid extraction from the well. It is necessary to remove the coiled tubing logging plug as otherwise a self-circulation situation occurs in which the fluid is pumped within the bypass-system. This can lead to self-circulating problems and, thus, to a damage of the electrical submersible pump.

Document <CIT> relates to retrieving a plug from a plug assembly of a production tubing.

In such situations it is known to stop the fluid extraction and exchange the bypass-system including the stuck coiled tubing logging plug. Said operation leads to high costs for the company because the fluid extraction has to be interrupted.

The object of the invention is to reduce the costs for situations in which the coiled tubing logging plug cannot be retrieved from the fluid tubing.

The object is solved by a system according to claim <NUM>.

Another object of the invention is to provide a method to reduce costs for situations in which the coiled tubing logging plug cannot be retrieved from the fluid tubing.

The invention is solved by a method according to claim <NUM>.

According to the invention it was recognized that it is possible to retrieve the coiled tubing logging plug from the fluid tubing by usage of a tool. In particular, it has been recognized that it is possible to retrieve the coiled tubing logging plug if the tool is adapted and formed such that it can pass partly through the through hole of the coiled tubing logging plug and that it comprises a retrieving portion that can be coupled with an inner sleeve of the coiled tubing logging plug of the coiled tubing logging plug. Such a tool enables to release the stuck coiled tubing logging plug and enables to retrieve the coiled tubing logging plug. Thus, it is not necessary anymore to remove the complete bypass system when the coiled tubing logging plug is stuck so that the operator saves costs by using the tool.

Retrieving a coiled tubing logging plug from a downhole means that the coiled tubing logging plug that is arranged downhole in the fluid tubing is retrieved from the downhole by moving the tool along a removal direction. A fluid can be extracted via the downhole. The fluid can be gas or a liquid, in particular oil.

The position to which the coiled tubing logging plug is moved can be a position within the through hole of the coiled tubing logging plug. That means, the coupling between the retrieving portion and the coiled tubing logging plug can occur within the through-hole. In particular, the part of the retrieving portion that is coupled with the coiled tubing logging plug is arranged within the through hole of the coiled tubing logging plug.

According to an embodiment the tool comprises a sealing portion for downhole sealing the through hole of the coiled tubing logging plug wherein the retrieving portion is connected with the sealing portion. The sealing portion seals the through hole of the coiled tubing logging plug. Thus, even for cases in which the coiled tubing logging plug cannot be retrieved by the tool it is possible to continue a fluid extraction operation by the electrical submersible pump without the risk that a self-circulation situation will occur.

The sealing portion is formed such that it prevents a fluid flow through the through-hole of the coiled tubing logging plug. This means, no fluid can flow from the fluid tubing of the bypass-system through the coiled tubing logging plug arranged in the fluid tubing into e.g. a production tubing fluidically connected to the bypass-system.

The sealing portion can be made from bulk or solid material. In particular, the sealing portion can be made from bulk or solid material such that no fluid can flow through the sealing body. Thus, no fluid can flow along the axial direction of the tool between an end of the tool directed to the production tubing and another end offset to the producing tubing. In the end, an easy shaped and formed tool can be provided in order to ensure the sealing function.

The sealing portion can have at least partially a cylindrical shape. In particular, the sealing portion can have an outer contour that at least partially is complementary in form with the through-hole of the coiled tubing logging plug. That means, the outer contour of said part of the sealing body is in contact with an inner part of the coiled tubing logging plug such that no fluid, in particular liquid, can pass through between said part of the sealing body and the part of the coiled tubing logging plug. Thus, it is ensured that the sealing portion can be inserted into the through hole of the coiled tubing logging plug and to seal the coiled tubing logging plug. The collapsible portion can be fixedly connected with the element body.

The sealing portion can comprise a first sealing portion and a second sealing portion wherein the diameter of the first sealing portion differs from the diameter of the second sealing portion. The diameter of the first sealing portion can be greater than the diameter of the second sealing portion. The fist sealing portion can have a diameter in the range of <NUM>,<NUM> to <NUM>,<NUM>. The second sealing portion can have a diameter in the range of <NUM>,<NUM> to <NUM>,<NUM>.

The first sealing portion and the second sealing portion can be arranged adjacent to each other along the axis of the tool. For sealing the coiled tubing logging plug the tool passes through sections of the coiled tubing logging plug that have different inner diameters. The tool enables to seal the coiled tubing logging plug at two sections of the coiled tubing logging plug having different inner diameter. This is possible as the outer contour of each of said two sealing body portions is complementary with the form of the respective part of the coiled tubing logging plug.

The first sealing body portion can seal an upper part of the coiled tubing logging plug. The upper part can comprise an end of the coiled tubing logging plug. The second sealing body portion can seal another part of the coiled tubing logging plug that is arranged lower than the upper part of the coiled tubing logging plug. The other part of the coiled tubing logging plug can be arranged between the ends of the coiled tubing logging plug. "upper" and "lower" refer to gravity direction.

The first sealing body portion is arranged in portion of the retrieving tool that has an extension between <NUM>-<NUM>% of the complete length of the tool. Said portion extends from an upper end of the tool, when the retrieving tool is inserted into the coiled tubing logging plug, and/or comprises the spacer portion and/or fishing portion.

The tool can comprise at least one sealing element arranged on the sealing portion, in particular the first sealing portion. In particular, the tool can comprises several sealing elements that are arranged on the sealing portion and that are arranged adjacent to each other along length direction of the tool. The sealing element can be an O-ring and/or can extend in circumferential direction of the sealing portion. In particular, the sealing element can be arranged in a groove of the sealing portion. The tool can comprise two sealing elements arranged on the first sealing portion. Additionally, the tool can comprise at least one sealing element, in particular two sealing elements, that is arranged on the second sealing portion. The sealing portion, in particular the first sealing portion and the second sealing portion, can be a portion of a tool body.

The tool body can comprise a fishing portion for fishing the tool. As fishing it is understood the operation of removing the tool from the coiled tubing logging plug and/or removing the tool and the coiled tubing logging plug by means of a fishing tool. The fishing portion is the part of the tool body which is coupled with a fishing tool during the fishing operation. The fishing portion can be arranged at an end of the tool body that is proximal to the production tube.

After the tool is inserted into through-hole of the coiled tubing logging plug the fishing portion is arranged outside the through-hole. This means, the fishing portion is not arranged inside the through-hole of the coiled tubing logging plug. Thus, a fishing tool can easily be connected with the fishing portion of the tool.

According to an embodiment of the invention the tool body can comprise a spacer portion for preventing that a sealing element gets into contact with a tubing wall during the movement of the tool towards the coiled tubing logging plug. Thus, it can be prevented in an easy way that the sealing element or sealing elements is or are damaged when the tool is moved towards the coiled tubing logging plug in order to insert the tool into the coiled tubing logging plug. The spacer portion can be arranged between the at least one sealing element and the fishing portion of the tool body. The tubing wall can be the wall of the production tubing.

The spacer portion can have a greater outer contour than the remaining part of the tool body. In particular, the diameter of the spacer portion can be greater than the diameter of the remaining part of the tool body. Thus, it can be secured in an easy way that the sealing element does not contact the tubing wall. The spacer portion can have a greater dimension than the through-hole of the coiled tubing logging plug. Thus, the spacer portion is not inserted into the through-hole of the coiled tubing logging plug but is arranged outside the through hole. That means, a part of the tool is arranged inside the through hole of the coiled tubing logging plug whereas the spacer portion is arranged outside the coiled tubing logging plug. As the spacer portion is arranged outside the through-hole it can also be used for fishing the tool for the case that the fishing portion is damaged and/or cannot be coupled with the fishing tool.

A particular advantageous tool is achieved if a distance between the spacer portion and a seating part of the tool is between <NUM>% to <NUM>% of the complete length of the tool. By choosing said length it can be secured that the sealing element does not come in contact with the tubing wall. The length of the tool is its extension in axial direction of the tool. The seating part of the tool is the tool part that comes in contact with the tubing wall during the movement of the tool in e.g. the production tubing. The retrieving portion can comprise the seating part.

According to an embodiment of the invention the retrieving portion can comprise other tool body and a retrieving element that is movable relative to the other tool body.

The retrieving element can surround the other tool body. This means that the other tool body is arranged within an interior of the retrieving element. In particular, the retrieving element can have a cylindrical shape.

The extension of the retrieving element in the length direction of the retrieving element can be shorter than the extension of the other tool body in the length direction. Thus, the retrieving element only surrounds a part of the other tool body in length direction of the retrieving element. The retrieving element can, in particular fully, surround the other tool body in circumferential direction of the other tool body. Thus, the retrieving element can be designed to be in form of a sleeve. The retrieving element can be translatorily movable relative to the other tool body and/or cannot rotate relative to the other tool body. In particular, the retrieving element can move along the length direction of the tool relative to the other tool body.

The retrieving element can be made from or comprise a solid body so that no fluid can flow through the retrieving element in axial or length direction of the retrieving tool. That means, the position of the retrieving element is not controlled by a liquid but a position change occurs mechanically as it is explained below more in detail.

The tool is not released or deactivated hydraulically to disengage it from the coiled tubing logging plug. In particular the tool is configured so that the tool does not allow fluid, in particular liquid, through or pressurized fluid, in particular liquid, to pass through with in the tool, as tool is from bulk or solid material. Additionally, in the tool there is no hydraulically connection or activation of parts but all connections between the parts can be mechanical.

The tool does not have any external ports or a meaning for hydraulics fluids movement to enter through the tool or interact with parts of the coiled tubing logging plug. The tool does not have any fluid chambers to help release the collects from the engagement area of the coiled tubing logging plug. Additionally, the tool does not allow annulus flow around it to pass through the coiled tubing plug due to the fact that it generates a seal in the upper sub of the coiled tubing plug. In addition, the tool does not have any holes, ports or cavities so that no fluid, in particular liquid, can pass through the tool. This is not possible as the tool is from bulk or solid material.

The retrieving element can comprise an element body and a collapsible portion that is movable relative to the element body. The collapsible portion enables that the tool can partly pass through the through hole of the coiled tubing logging plug. As the cross section of the through hole can change along the length direction of the coiled tubing logging plug, the collapsible portion enables in an easy way that the retrieving element can be inserted into the through hole and pass through the through hole of the coiled tubing logging plug without to stuck. This is possible because the collapsible portion can move in a radial direction relative to the element body in order to reduce its cross section and thus avoid that the retrieving element cannot move further within the through hole of the coiled tubing logging plug.

The collapsible portion and the element body can be a single piece component. This means, the retrieving element is formed as a single piece component. The collapsible portion can comprise at least one finger or a plurality of fingers that are arranged adjacent to each other in circumferential direction of the collapsible portion. The finger can be connected at one end with the element body.

If a plurality of fingers are provided, a space can be provided between the respective fingers in circumferential direction of the retrieving element. In particular, the fingers can be arranged such that they can move relative to each other.

The collapsible portion can have a hook-shaped end. In particular, another end of the finger that is distal to the element body can be hook-shaped. The hook-shape simplifies to couple the retrieving element and the coiled tubing logging plug, in particular an inner sleeve of the coiled tubing logging plug, when the coiled tubing logging plug is retrieved.

The collapsible portion can be formed such that a plane exists comprising the collapsible portion and the other tool body and in which the collapsible portion has an inner cross section, in particular an inner diameter, that is greater than an outer cross section of the other tool body, in particular an outer diameter. This enables that the collapsible portion can move towards the other tool body. In particular, the collapsible portion can move from a collapsed state to an expanded state or vice versa in radial direction of the tool. In the collapsed state the tool can be moved through the coiled tubing logging plug. In the expanded state the coiled tubing logging plug can be retrieved by the tool and/or cannot be moved within the through hole of the coiled tubing logging plug. In order to move through the through hole the collapsible portion has to be transferred to the collapsed state. This can be done by a protrusion of an inner sleeve of the coiled tubing logging plug when the tool is moved within the through hole.

The tool, in particular the hook shaped end of the collapsible portion, can engage a lower sub end of the coiled tubing plug and/or can engage the protrusion of the inner sleeve of the coiled tubing logging plug, allowing the external sleeve locking dogs to retract radially and release the plug from its position.

In the retrieving process the tool has to pass through a specific geometry and dimensions, in particular changes of inner diameters, of the coiled tubing plug to reach the bottom lower sub which is the end of the coiled tubing plug. Then the retrieving tool can engage the protrusion of the inner sleeve of the coiled tubing logging plug, allowing the external sleeve locking protrusion or locking dogs to retract radially and release the plug from its position and retrieve it from the Y tool nipple.

The retrieving element can be moved into a retracted position when the tool is inserted into, in particular moved within, the coiled tubing logging plug. Additionally, the retrieving element can be arranged in a retrieving position when the tool retrieves the coiled tubing logging plug. In particular, the collapsible portion can be arranged in the collapsed state when the retrieving element is arranged in and/or moved to the retracted position. Thus, it is possible that the retrieving element being in the collapsed state can at least partly pass through the through hole of the coiled tubing logging plug.

The retrieving element, in particular the collapsible portion, can seat on the other tool body, in particular on an abuting portion of the other tool body, when the retrieving element is in the retrieving position. The tool body prevents that the collapsible portion can be transferred to the collapsed state in which the tool cannot retrieve the coiled tubing logging plug. Thus, the tool can be formed such that the collapsible portion can only be moved into the collapsed state when the retrieving element is in the retracted position and/or is not in the retrieving position.

According to an embodiment of the invention the tool can comprise a shifting member for shifting the retrieving element from the retracted position to the retrieving position or vice versa. Thus, the transfer of the retrieving element from the retracted position to the retrieving position can occur easily. In particular, the shifting member can be tensioned when the retrieving element is moved from the retrieving position to the retracted position. This can happen when the tool is inserted into the through hole and the inner protrusion of the inner sleeve of the coiled tubing logging plug prevents that the collapsible portion in its expanded position passes through the through hole of the coiled tubing logging plug. Thus, a further movement of the tool leads to that the inner protrusion of the inner sleeve of the coiled tubing logging plug causes that the retrieving element is moved towards the retracted position when the tool is moved through the through hole of the coiled tubing logging plug. The shifting member can be a spring. The collapsible portion is transferred to the collapsible state by the inner protrusion of the inner sleeve of the coiled tubing logging plug when the tool is further moved along the insertion direction.

The shifting member can only be operated as mechanically, in other words tensioned mechanically when the retrieving element moved from retrieving position to retracted position. Hence no fluid movement or pressurized fluid is required to activate the shifting member mechanism, as the retrieving element is solid bulk material. Additionally, the shifting member can apply a force on the retrieving element to move it from the retracted position to the retrieving position. The retrieving element can be moved by means of the shifting member when the collapsible portion is in the collapsed state. The shifting member can be arranged on the tool body.

The protrusion of the inner sleeve of the coiled tubing logging plug can prevent that the retrieving element passes further when the collapsible portion is in the expanded position. This is possible because the inner diameter of the through hole of the protrusion of the inner sleeve of the coiled tubing logging plug is smaller than the outer diameter of a part of the collapsible portion being in the expanded state. The protrusion is arranged between the two ends of the through hole of the coiled tubing logging plug.

The tool body and the other tool body can be connected to each other in a detachable matter and/or can be arranged coaxially to each other. This means that the tool comprises two parts that can be connected to each other. The provision of two parts simplifies to attach the retrieving element to the other tool body.

The retrieving element and the other tool body can be arranged coaxially to each other. In addition, the retrieving element can be arranged partially on the tool body and the other tool body. The hook shaped end of the finger of the collapsible portion can have a greater diameter than the other tool body.

The tool can be formed such that the shifting member can abut against one end on the tool body and against another end on the retrieving element. Additionally, the element body can abut against the other tool body when the retrieving element is in the expanded position and/or the element body cannot abut against the other tool body when the retrieving element is in the retracted position.

Of particular advantage is a well system that comprises a coiled tubing logging plug and a tool according to the invention.

The well completion system can comprise a bypass-system, wherein the coiled tubing logging plug is located at a seating element of a fluid tubing of the bypass-system. That means, the tool is in direct contact with the coiled tubing logging plug and/or is not in direct contact with the fluid tubing. The seating element can be a part of the fluid tubing that protrudes in a radial inner direction from the remaining part of the fluid tubing. The well system can be fluidically connected with the production tubing.

The bypass-system comprises a further fluid tubing. A pump of the well system, in particular an electrical submersible pump, can be arranged in the further fluid tubing and/or can be fluidically connected with the further fluid tubing. The further fluid tubing is arranged partially parallel to the fluid tubing. The two tubings are fluidically connected with each other at their upper and lower end.

An outer contour of a cross section of the tool is smaller than an outer contour of a cross section of the coiled tubing logging plug. In particular, an outer diameter of the tool is smaller than an outer diameter of the coiled tubing logging plug. Additionally, the outer diameter of the sealing body, in particular the first sealing body portion and the second sealing body portion, is smaller than an inner diameter of the fluid tubing. In other words, the tool cannot seal the fluid tubing. The same applies if the tool is used in the further tubing in which the electrical submersible pump is arranged. The tool can be coaxially arranged with the coiled tubing logging plug after the tool is arranged in the through hole of the coiled tubing logging plug.

The coiled tubing logging plug can comprise the inner sleeve comprising the protrusion. The protrusion can protrude from the remaining part of the inner sleeve in radial direction towards a middle axis of the inner sleeve. Additionally, the coiled tubing logging plug can comprise an outer sleeve of the coiled tubing logging plug. The inner sleeve can comprise a recess for receiving of another protrusion of an outer sleeve of the coiled tubing logging plug. The outer sleeve and the inner sleeve can be arranged coaxially to each other. The inner sleeve can at least partly be arranged in an interior of the outer sleeve. The inner sleeve and the outer sleeve can move relative to each other.

In the following, the method for retrieving the coiled tubing logging plug is described. After it is determined that the coiled tubing logging plug is stuck and cannot be removed from a fluid tubing of a bypass-system a tube passing through the coiled tubing logging plug can be cut. The tube passes completely through the coiled tubing logging plug. The coiled tubing logging plug is fixedly seated on the seating element of the fluid tubing.

As a result of the cutting step a part of the cut tube falls downward due to gravity force. The remaining part of the cut tube can be removed in the next step. Afterwards, the tool can be moved along the insertion direction until a part of the retrieving element has passed the protrusion of the inner sleeve of the coiled tubing logging plug. The inner sleeve, in particular the protrusion of the inner sleeve, can be adapted to act on the collapsible portion such that it moves from the expanded state to the collapsed state when the tool is moved through the through hole of the coiled tubing logging plug.

In particular, in a first step the retrieving element can move from the retrieving position to the retracted position when the protrusion of the inner sleeve comes into contact with the collapsible portion. After the retrieving element is arranged in the retracted position and if the tool is further moved within the through hole of the coiled tubing logging plug the protrusion of the inner sleeve can apply such a force on the collapsible portion so that the collapsible portion is transferred into the collapsed state. Afterwards, the retrieving element can pass through the through hole, in particular through the through hole of the protrusion, when the tool is further moved through the through hole of the coiled tubing logging plug. After passing the protrusion of the inner sleeve, the collapsible portion is transferred to the extracted state. This is possible as the collapsible portion is tensioned when it is moved from the expanded state to the collapsed state.

In the next step the tool can be moved along the removal direction so that the retrieving element, in particular the hook shaped end of the collapsible portion, gets into contact with the protrusion of the inner sleeve of the coiled tubing logging plug. The retrieving element applies a force on the protrusion of the inner sleeve in order to retrieve the coiled tubing logging plug. The force is applied such that the other protrusion of the outer sleeve inserts into the recess of the retrieving element when the coiled tubing logging plug is retrieved. This is possible as the inner sleeve moves relative to the outer sleeve due to the force applied on the protrusion. After the other protrusion is inserted within the recess the coiled tubing logging plug can be moved along the removal direction. The electrical submersible pump can be activated so that it pumps the fluid through the bypass system towards the production tubing after the coiled tubing logging plug is retrieved and a blanking plug has been inserted into the fluid tubing.

For the case that the tool cannot retrieve the coiled tubing logging plug, the tool is moved such along the insertion direction that the sealing portion seals the coiled tubing logging plug. In particular, at least one sealing element of the sealing portion is in contact with coiled tubing logging plug so that the coiled tubing logging plug is sealed. Thus, the tool shows the advantage that it ensures to restore the well production even though the coiled tubing logging plug could not be retrieved by the tool.

According to an embodiment the tool running procedures can be done using coiled tubing bottom hole assembly with standard ball drop hydraulic release disconnect, hence once the retrieving tool lands inside the coiled tubing, and fishing process deemed unsuccessful then a ball will be dropped to activate a disconnect to separate the retrieving tool from the coiled tubing bottom hole assemble leaving the tool inside the coiled tubing plug to seal it allowing the well to flow via ESP. The tool is not be connected to drill pipe or production tubing but to coiled tubing bottom hole assembly. Plus the tool has a bumper made of steel to seal the coiled tubing plug should the retrieving process deemed not possible. As well the upper part of the tool in particular, the fishing portion and the tapering end portion, can be arranged at opposite ends of the tool. The fishing portion can be connected with a fishing tool when the tool retrieves the coiled tubing logging plug. The retrieving tool can be designed for specific oil producing wells with Y tool completion design (artificial lift completion) and meant to fish and retrieve the coiled tubing plug or if not possible then to seal the flow through coiled tubing plug and allow production through production tubing and ESP pump side.

In the figures, the subject-matter of the invention is schematically shown, wherein identical or similarly acting elements are usually provided with the same reference signs. Here shows:.

The tool <NUM> shown in <FIG> is used to retrieve a coiled tubing logging plug <NUM> from a downhole that is stuck in fluid tubing <NUM> of e.g. a bypass system. The tool <NUM> comprises a sealing portion <NUM> for downhole sealing a through hole <NUM> of a coiled tubing logging plug <NUM>. The sealing portion <NUM> has a first sealing portion 29a and a second sealing portion 29b wherein the first sealing body portion 29a and the second sealing body portion 29b are arranged adjacent to each other along the axial direction of the tool <NUM>. The first sealing portion 29a has a greater diameter than the second sealing portion 29b.

Additionally, the tool <NUM> comprises a retrieving portion <NUM> for retrieving the coiled tubing logging plug <NUM> from the downhole wherein the retrieving portion <NUM> is connected with the second sealing portion 29b. The sealing portion <NUM> and the retrieving portion <NUM> are configured and formed to be insertable into the through hole <NUM> of the coiled tubing logging plug <NUM>. The coiled tubing logging plug <NUM> and the fluid tubing <NUM> are shown in <FIG>.

The sealing portion <NUM>, in particular the first sealing portion 29a and the second sealing portion 29b, is part of a tool body <NUM>. The retrieving portion <NUM> comprises other tool body <NUM> and a retrieving element <NUM>. The retrieving element <NUM> is movable relative to the other tool body <NUM> along a length direction L of the tool <NUM> and can be coupled to the coiled tubing logging plug <NUM> in order to retrieve the coiled tubing logging plug <NUM>. The length direction L corresponds with the axial direction of the tool <NUM>.

The retrieving element <NUM> surrounds the other tool body <NUM> in circumferential direction of the other tool body <NUM>. In length direction L of the tool <NUM> the other tool body <NUM> is longer than the retrieving element <NUM>. The retrieving element <NUM> is formed as a one part component and comprises an element body <NUM> and a collapsible portion <NUM>. The collapsible portion <NUM> comprises a plurality of fingers <NUM> that are arranged adjacent to each other along the circumferential direction of the retrieving element <NUM>. One end of the fingers <NUM> is connected with the element body <NUM>, respectively. The other end of the finger <NUM> has a hook-shape <NUM>. The collapsible portion <NUM> can be moved relative to the element body <NUM>. In particular, the collapsible portion <NUM> moves in radial direction R of the tool <NUM> relative to the element body <NUM>.

The tool <NUM> comprises a tapering end portion <NUM> arranged at one end of the tool <NUM>. The tapering end portion <NUM> decreases in a direction away from the retrieving element <NUM>. The tool <NUM> comprises a fishing portion <NUM> that is arranged at another end of the tool <NUM>. In particular, the fishing portion <NUM> and the tapering end portion <NUM> are arranged at opposite ends of the tool <NUM>. The fishing portion <NUM> is connected with a non-shown fishing tool when the tool <NUM> retrieves the coiled tubing logging plug <NUM>.

The tool <NUM> comprises a spacer portion <NUM> that is arranged between the fishing portion <NUM> and the retrieving element <NUM>. The spacer portion <NUM> has a greater diameter than the remaining part of the tool <NUM>. As can be seen in <FIG> the spacer portion <NUM> remains outside the through-hole <NUM> when the retrieving tool <NUM> is inserted into the through-hole <NUM> of the coiled tubing logging plug <NUM>.

The tool <NUM> comprises a plurality of sealing elements <NUM>. The sealing elements <NUM> are formed as O-rings and are arranged in grooves of the sealing portion. Additionally, the sealing elements <NUM> are arranged adjacent to each other along the length direction L of the tool <NUM>. The sealing elements <NUM> are arranged on the first sealing portion 29a and the second sealing portion 29b.

<FIG> shows a cross section of the tool shown in <FIG>. The tool body <NUM> and the other tool body portion <NUM> are connected with each in a removable manner. The tool body <NUM> comprises the spacer portion <NUM>, the sealing portion <NUM> and the fishing portion <NUM>. The other tool body <NUM> comprises the tapering end portion <NUM>.

The retrieving element <NUM> has the form of a sleeve. The element body <NUM> is partly arranged on the tool body <NUM> and partly on the other tool body <NUM>. A shifting member <NUM> that can be a spring is arranged between the tool body <NUM> and the element body <NUM>. The shifting member <NUM> is in contact with the tool body <NUM> and the retrieving element <NUM>, in particular the element body <NUM>.

The collapsible portion <NUM> and the other tool body <NUM> are designed such that a plane E exist comprising the collapsible portion <NUM> and the other tool body <NUM> wherein the collapsible portion <NUM> has a greater inner diameter than an outer diameter of the other tool body <NUM>. Thus, a space exists between the collapsible portion <NUM> and the other tool body <NUM> in radial direction R of the tool <NUM>.

<FIG> shows a state of the tool <NUM> in which the retrieving element <NUM> is arranged in an expanded position. In the expanded position the collapsible portion <NUM> cannot be transferred in an collapsed state. This is prevented by an abuting part <NUM> of other tool body <NUM> as is explained below more in detail. In the expanded position of the retrieving element <NUM> the element body <NUM> abuts against the other tool body <NUM>. The other tool body <NUM> comprises a cylindrical portion between the abuting portion <NUM> and the tapering portion <NUM>. This cylindrical portion has a length ensuring that the tapering portion <NUM> is at least partly arranged outwards the coiled tubing logging plug <NUM> when the tool <NUM> is arranged in the coiled tubing logging plug <NUM>.

In the following, the method for retrieving the coiled tubing logging plug <NUM> by means of the tool <NUM> is described. The method is described under usage of <FIG>.

<FIG> shows a part of a well system <NUM> in a state in which the coiled tubing logging plug <NUM> is stuck. This means that the connection between the coiled tubing logging plug <NUM> and the fluid tubing <NUM> cannot be released so that the coiled tubing logging plug <NUM> cannot be moved in a removal direction O. The removal direction O is opposite to an insertion direction I of the tool <NUM>.

The coiled tubing logging plug <NUM> seats on a seating element <NUM> of the fluid tubing <NUM>. A tube <NUM> extends through the complete coiled tubing logging plug <NUM>, in particular through the through-hole <NUM> of the coiled tubing logging plug <NUM>. <FIG> shows only a part of the tube <NUM>.

After, it has been determined that the coiled tubing logging plug <NUM> is stuck, the tube <NUM> is cut. The tube <NUM> can be cut at a portion that is arranged above the coiled tubing logging plug <NUM>. <FIG> shows the cutting position <NUM> at which the tube <NUM> is cut.

One part of the cut tube <NUM> falls downwards due to gravitationally force. This part is shown in <FIG> whereas the other cut tube part has been removed by moving it along the removal direction O. The removal direction O is opposite to the insertion direction I.

<FIG> shows the well system <NUM> according to <FIG> after the tool <NUM> is inserted into the through hole <NUM> of the coiled tubing logging plug <NUM>. <FIG> shows the encircled part of the well system <NUM> shown in <FIG>.

From <FIG> it is evident that the coiled tubing logging plug <NUM> comprises an inner sleeve <NUM> and an outer sleeve <NUM>. The outer sleeve <NUM> is formed such that it surrounds the inner sleeve <NUM>. The inner sleeve <NUM> comprises a protrusion <NUM> that protrudes towards the retrieving element <NUM>. In particular, the protrusion <NUM> protrudes radially inwards. The coiled tubing logging plug <NUM> comprises a spring <NUM> that is connected with the protrusion <NUM>.

The outer sleeve <NUM> comprises another protrusion <NUM> that is arranged in an extended position. The other protrusion <NUM> can be transferred to collapsed position, in which it engages into a recess <NUM> of the coiled tubing logging plug <NUM>. The recess <NUM> can be arranged in the inner sleeve <NUM>. At <FIG> the other protrusion <NUM> cannot be transferred into the collapsed position as a part of the inner sleeve <NUM> prevents said transfer. In particular, a part of the outer sleeve <NUM> lies directly on a part of the inner sleeve <NUM>.

When the tool <NUM> is moved within the through hole <NUM> of the coiled tubing logging plug <NUM> along the insertion direction I the retrieving element <NUM>, in particular the hook shaped end <NUM> of the finger <NUM> gets into contact with the protrusion <NUM> of the inner sleeve. As the hook shaped end <NUM> of the finger <NUM> has a greater diameter than the inner diameter of the protrusion <NUM> the retrieving element <NUM> cannot move along the insertion direction I so that the other tool body <NUM> moves relative to the retrieving element <NUM>. This is not shown in <FIG>.

After the retrieving element <NUM> is moved to the retracted position a further movement of the tool <NUM> leads to that the collapsible portion <NUM> is transferred into the collapsed state by means of the protrusion <NUM>. Afterwards, the collapsible portion <NUM> being in the collapsed state and, thus, the retrieving element <NUM> can be moved through the protrusion <NUM> when the tool <NUM> is moved along the insertion direction I.

The shifting member <NUM> shifts the retrieving element <NUM> to the retrieving position after the collapsible portion <NUM> is transferred to the collapsed state. After the collapsible portion <NUM> has passed the protrusion <NUM> the collapsible portion <NUM> moves back into the expanded state. The tool <NUM> is moved to such a position in which the hook shaped end <NUM> of the finger <NUM> is not in contact with the protrusion <NUM>. This state is shown in <FIG>.

The tool <NUM> is moved relative to the coiled tubing logging plug <NUM> until the spacer portion <NUM> abuts against the coiled tubing logging plug <NUM>. Said state is shown in <FIG>. In said state the retrieving portion <NUM> and the sealing portion <NUM> are arranged within the through hole <NUM> of the coiled tubing logging plug <NUM>. Due to the sealing portion <NUM>, in particular the sealing elements <NUM>, it is secured that no fluid can flow through the through hole <NUM> of the coiled tubing logging plug <NUM>.

Afterwards, the tool <NUM> is moved along a removal direction O that is opposite to the insertion direction I. The retrieving element <NUM>, in particular the hooked shaped end <NUM> of the finger <NUM> comes into contact with the protrusion <NUM>. At said state the spacer portion <NUM> is not in contact with the coiled tubing logging plug <NUM>. Said state is shown in <FIG>.

The collapsible portion <NUM> cannot be transferred into the collapsed state as the collapsible portion <NUM>, in particular the hook shaped end <NUM> of the finger <NUM>, abuts against the abuting part <NUM> of the other tool body <NUM>. That means, the abuting part <NUM> prevents that the collapsible portion <NUM> moves to the collapsed state. In said state at least a part of the sealing portion <NUM> is still arranged within the through hole <NUM>. Thus it is secured that the no fluid can flow during the removal of the coiled tubing logging plug <NUM>.

By further moving the tool <NUM> along removal direction O the retrieving element <NUM> applies a force against the protrusion <NUM>. This force leads to that the inner sleeve <NUM> moves relative to the outer sleeve <NUM>. In particular, the inner sleeve <NUM> moves along the removal direction O. Due to the movement of the retrieving element <NUM> and the inner sleeve <NUM> along the removal direction O the recess <NUM> is also moved. The recess <NUM> is moved to such a position in which the other protrusion <NUM> can insert into the recess <NUM>. This movement is necessary as otherwise the coiled tubing logging plug <NUM> cannot be removed from the fluid tubing as the other protrusion <NUM> would otherwise abut against a wall of the fluid tubing <NUM>.

<FIG> shows the well system <NUM> according to <FIG> after the tool <NUM> retrieves the coiled tubing logging plug <NUM> from the fluid tubing <NUM>. The tool <NUM> can be moved into a production tubing <NUM> of the well system <NUM> shown in <FIG>. In particular, <FIG> shows the tool <NUM> in a state of sealing the coiled tubing logging plug <NUM> in case the plug was not retrieved as e.g. the spacer portion <NUM> is locked against the upper sub of the coiled tubing logging plug <NUM> allowing the sealing elements <NUM> to seal the fluid tubing <NUM> and well production to be restored.

<FIG> shows a well systems <NUM> with a bypass-system <NUM>, the tool <NUM> and the coiled tubing logging plug <NUM>. The tool <NUM> is arranged inside the coiled tubing logging plug <NUM>.

The bypass-system <NUM> comprises a Y-tool. The Y-tool comprises the fluid tubing <NUM> discussed above. Additionally, the bypass-system <NUM> comprises a further fluid tubing <NUM> that is arranged parallel to the fluid tubing <NUM>. A pump <NUM> is arranged in the further fluid tubing <NUM> wherein the pump <NUM> can be an electrical submersible pump. The bypass-system <NUM> is fluidically connected with a production tubing <NUM>. The production tubing <NUM> is arranged above the bypass system <NUM>. Additionally, the production tubing <NUM> is fluidically connected to the bypass system <NUM>, in particular to the fluid tubing <NUM> and the further fluid tubing <NUM>.

Claim 1:
Well system comprising a coiled tubing logging plug and a tool (<NUM>) comprising
a retrieving portion (<NUM>) for retrieving the coiled tubing logging plug (<NUM>) from a downhole wherein the retrieving portion (<NUM>) is configured and formed to be insertable into a through hole (<NUM>) of the coiled tubing logging plug (<NUM>) and to be coupleable with the coiled tubing logging plug (<NUM>) in order to retrieve the coiled tubing logging plug, wherein
the retrieving portion (<NUM>) comprises another tool body (<NUM>), a retrieving element (<NUM>) that is movable relative to the other tool body (<NUM>), an element body (<NUM>) and a collapsible portion (<NUM>) that is movable relative to the element body (<NUM>), wherein
the coiled tubing logging plug (<NUM>) comprises an inner sleeve (<NUM>) comprising a protrusion (<NUM>) that is adapted to act on the collapsible portion (<NUM>) such that it moves from the expanded state to the collapsed state when the tool (<NUM>) is moved through the through hole (<NUM>) of the coiled tubing logging plug (<NUM>), and the coiled tubing logging plug (<NUM>) comprises a recess (<NUM>) for receiving of another protrusion (<NUM>) of an outer sleeve (<NUM>) of the coiled tubing logging plug (<NUM>), wherein
the retrieving element (<NUM>) is configured to apply a retrieving force on the protrusion (<NUM>) of the inner sleeve (<NUM>) and to cause the inner sleeve (<NUM>) to move such that the other protrusion (<NUM>) of the outer sleeve (<NUM>) is received in the recess (<NUM>) of the inner sleeve (<NUM>) when the coiled tubing logging plug (<NUM>) is retrieved.