A drill pipe string conveyed bridge plug running tool and a method for forming and verifying a cement plug

Introduction

The present invention relates to a running tool for a mechanical bridge plug in a petroleum well. More specifically, it relates to a running tool also arranged for working as a cementing tool, while further also arranged for working as a dressing and tagging tool.

Background Art

A petroleum well section may be cement plugged in the casing at a given depth for several reasons. The plug may be formed either for permanent plug and abandon (PPA), temporary plug and abandoning (TPA) or for drilling a side-track or removing and replacing or otherwise remedying the casing above the plug. The cement plugging process is usually conducted by the following steps:

- Run in, into the cased well, a bridge plug conveyed on a J-slot tool at a lower end of a wireline or drill pipe string,

- Set the bridge plug in the casing, either by mechanical manipulation or hydraulic setting. The bridge plug is now set in the casing to form a basis for forming a later circulated in cement plug,

- Left Hand (LH) rotating the drill pipe string while slacking off/weight loading the J- slot running tool in order to disconnecting the J-slot running tool from a corresponding J-slot stinger at the top of the bridge plug,

- Pull Out Of Hole (POOH) the J-slot running tool,

- Run In Hole (RIH) a cementing stinger to bridge plug and Pull Up (PU) while cementing entire length of cement plug, i.e. 50m. - Pull Out Of Hole (POOH) cementing stinger,

- Run In Hole (RIH) a Drill Pipe (DP) conveyed dress and tag tool and dress away low quality upper part of cement plug until expected proper quality hardened cement is exposed to the dress and tag tool,

- Weight load the tag tool to tag the top of the cement plug exposed, to verify the cement plug.

It is possible, but not desirable from a cement plug quality point of view, to shorten the above sequence by replacing, after disconnecting the J-slot running tool from the J-slot stinger, by circulating in the cement through the J-slot running tool' connector sleeve and imperfectly dress and tag, if at all possible, the so formed cement plug. However, a J-slot connector sleeve has a rather broad inner 0 and large outer 0 and is poorly designed for cementing, and would dress and tag the cement plug only peripherally thus imperfectly.

A petroleum oil tool provider usually has a repository of drill pipe conveyed J-slot running tools adapted for being connected to a J-slot stinger on top of a wide variety of diameters and types of casing plugs. The plugs may be of various types such as

- removable bridge plugs (RBP),

- temporary DP string hang-off plugs,

- pressure test plugs, and

- permanent bridge plugs such as for forming a cementing base.

It is desirable to have a common J-slot stinger interface on top of most or all of such casing plugs in order to keep the logistics' number of tools low, both to reduce required on-board storage space on the drilling or intervention platform, and offshore or land transport costs.

US2019/0390527A1, Telfer, Ardyne Holdings Ltd, UK, "Improvements in or relating to well abandonment and slot recovery", describes a method and apparatus for single-trip cementing and casing cutting for well abandonment and slot recovery. Using a tool string including a casing cutter and a stinger, where the casing cutter has a central through bore including a wall to isolate the cutting assembly from the cement, cement can be passed through the cuter and deposited using the stinger to form a plug. The method preferably includes the additional steps of including a bridge plug on the tool string and setting the bridge plug in the well before passing fluidised plugging material through the stinger to deposit a quantity of fluidised plugging material into the well bore to form a cement plug.

NO20151699A1 , Sorhus, Archer Oiltools AS, NO, "Drill pipe string conveyed pressure integrity test tool and method for testing the pressure integrity of a casing", describes a method of testing the pressure integrity of a casing, comprising: - providing a drill pipe string conveyed pressure integrity tool section for a casing, comprising: - a cylindrical tool stem having an axial bore and upper and lower tool joints to said drill pipe string and a drilling or milling bit; - a relative downward annulus flow closing check valve comprising a check valve body on said tool stem, - running said testing tool section to a target depth in the casing with the check valve open, - halting the test tool section at target depth, - increasing pressure in the casing bore to displace the check valve to its lower, closing position, - verifying integrity of the casing above the swab cup.

NO 20201359A1 , Herabakka Glinda, Archer Oiltools AS, NO, “A drill pipe string conveyed bridge plug running tool and a method for forming and verifying a cement plug” relates to a method of forming and verifying a cement plug in a single run in a casing bore, comprising the steps of: -assembling a bridge plug on a drill-pipe string conveyed through-bore bridge plug running tool, -said bridge plug running tool comprising a cementing stinger portion releasably connected to an upper part of said bridge plug, -said bridge plug running tool further comprising dress-cutting wings arranged above a base of said cementing stinger portion, -running into a well said bridge plug on said running tool to a target depth, -setting said bridge plug in the casing, -pulling up on said drill pipe string to disconnect said stinger portion from said bridge plug, -using said stinger portion, circulating in cement slurry on top of said bridge plug to form a cement plug in said casing, -allowing said cement plug to set and harden, -using said running tool dressing a top of said cement plug, -using said running tool tagging said dressed cement plug to verify its quality.

Brief summary of the invention

The present invention provides a solution to the problems which may arise when one wants to take into account this overall goal of having a common J-slot stinger interface on top of the variety of plugs on board a drilling or intervention platform. The invention further facilitates the onshore preparation of plugs so as for all or most DP conveyed plugs, also those for permanent plug and cementing, to have a common J-slot stinger type top interface.

The invention is a drill pipe string conveyed bridge plug running tool (100) comprising

- an axially extending mandrel (1) with an upper connection (101) to a drill pipe string and provided with a through bore (102) ; wherein said through bore (102) extending to a lower portion of said mandrel (1) and continued into a cylindrical sleeve-shaped stinger portion (103),

- said cylindrical sleeve-shaped stinger portion (103) further arranged for being releasably connected into a main bore (224) of a J-slot top stinger (226) of a bridge plug (200, 201) arranged for being set in a casing,

- said cylindrical sleeve-shaped stinger portion (103) arranged for being released from said bridge plug (200, 201) and for depositing cement on top of said bridge plug (200, 201),

- said mandrel (1) having two or more radially extending dress-cutter blades (108) arranged for dress-cutting into a top of said deposited cement plug when set and hardened,

- said dress-cutter blades (108) provided with two or more dress-cutter edges (182) extending radially beyond said cylindrical sleeve-shaped stinger portion (103) and arranged for cutting axially into the top of said cement plug when set and hardened, - said dress-cutter blades (108) and said cylindrical sleeve-shaped stinger portion (103) arranged for tagging the resulting dressed cement plug surface.

The invention is defined in the attached independent claims 1 and 13. Embodiments of the invention are defined in the claims depending on those independent claims.

Brief Figure captions

Fig. 0 is a series of simplified vertical sections of a method according to the present invention, showing an embodiment with circulation blind sub, comprising running in and setting of a bridge plug (leftmost illustration), releasing the running tool's cylindrical sleeve-shaped stinger portion (103) from a J-slot top stinger of the bridge plug (second illustration), circulating in cement slurry via the running tool's cylindricl sleeve-shaped stinger portion (103) (third illustration), pulling up and circulating excess cement slurry (fourth illustration), and allowing a cement plug to set and harden, dressing off a top of the set cement plug (fifth illustration), and tagging the cement plug (sixth illustration), and pulling up or out of hole (rightmost illustration).

Fig. 1 is an elevation view of a bridge plug running tool according to the present invention, wit circulation blind sub in a lateral view, and top end view, the bridge plug running tool assembled and connected to a bridge plug J-slot stinger top section. It is also shown an end view. Please notice that what we call a "J-slot top stinger" is a top stinger with radial dogs or knobs, the dogs or knobs otherwise arranged for interacting with J-slots in a J-slot running tool. A J-slot running tool is not used in the present invention due to the need for running a dressing and tagging operation in the same run as setting the bridge plug and cementing. A J-slot running tool is not particularly useful for dressing and tagging due to its large diameter and wide aperture in the lower end.

Fig. 2 is an axial section view of figure 1. A section view at B-B illustrates a section of the connector/J-slot stinger portion of the bridge plug running tool mounted with shear screws, the cylindrical sleeve-shaped stinger portion (103), arranged for cementing and mounted inside the top portion of the J-slot top stinger of the bridge plug. Fig. 2 shows an assembled bridge plug running tool (100) and a bridge plug top, in longitudinal section view.

Fig. 3 is a perspective view of the bridge plug running tool assembled for running in with the J-slot top stinger of the bridge plug. Fig. 3 is a perspective view in assembled state of the bridge plug running tool (100) and the bridge plug's (200) (not shown) J-slot top stinger (226).

Fig. 4 is an elevation view of a bridge plug running tool according to the invention, the bridge plug running tool disconnected to the bridge plug J-slot stinger top section.

Fig. 5 is an axial section view of the same as shown in Fig. 4, here in the disconnected state. Fig. 5 is a longitudinal section view after disconnection of the bridge plug running tool (100) from the bridge plug's (200) (not shown) J-slot top stinger (226).

Fig. 6 is a perspective view of the bridge plug running tool assembled for running in with the J-slot top stinger of the plug. Fig. 6 shows a perspective view after disconnect of the bridge plug running tool (100) from the bridge plug's (200) (not shown) J-slot top stinger (226). Shear screws (118) are broken.

Fig. 7 illustrates the bridge plug (200) running tool (100) with a cylindrical sleeveshaped stinger portion (103), arranged for subsequent cementing, connected into a J-slot top stinger (226) in a section view. The J-slot top stinger (226) is further connected to a through bore (202) bridge plug (201) with a valve (203), e.g. a ball valve in the through bore (202). In order to test for the bridge plug's (201) pressure integrity from below, set the plug by setting the slips (211) and the packer (212), have open the valve (203) and set pressure in the drill pipe string through bore. When having verified the integrity of the bridge plug (201), close the valve (203), lift on the drill pipe string and shear the shear screws (118) and elevate the cementing stinger portion (103) above the J-slot top stinger (226), and circulate in cement on top of the bridge plug (201).

Fig. 8 illustrates an embodiment of the bridge plug running tool (100) with a cylindrical sleeve-shaped stinger portion (103) connected to J-slot top stinger (226), a valve (227) in the J-slot top stinger (226). In order to pressure test, set slips (211) and packer (212), open valve (227) and set pressure in the drill pipe string. The circulation ports (119) in the cylindrical sleeve-shaped stinger portion (103) of the bridge plug running tool (100) are covered by the J-slot top stinger (226) sleeve which is held in place by the shear screws (118). When the pressure test is OK, close the valve (227), e.g. by rotation of an outer sleeve of the J-slot top stinger (226) relative to an inner sleeve of the J-slot top stinger, pull up to shear the shear screws (118), and circulate in cement via the cylindrical sleeve-shaped stinger portion (103).

Fig. 9a is a lateral view of an embodiment of the bridge plug running tool (100) with the cementing cylindrical sleeve-shaped stinger portion (103) of the running tool mounted inside the top of a J-slot top stinger (226) which shall be further mounted on the top portion of a bridge plug (200, 201).

Fig. 9b illustrates in a longitudinal axial section an embodiment with lateral stinger ports and rupture disc, section view with J-slot top stinger (226) for bridge plug (201).

Fig. 9c is a top end view of the embodiment according to Fig. 9a.

Fig. 9d is a detail D according to Fig. 9b.

Fig. 9e is a lateral view of an embodiment of the bridge plug running tool (100) with its cementing cylindrical sleeve-shaped stinger portion (103) extending axially beyond the dress-cutter blades (108), and showing the (unbroken) shear screws (118) and the circulation ports (119( and the seal ring (120). Fig. 9f is a perspective view of the bridge plug running tool (100) attached with its cylindrical sleeve-shaped stinger portion (103) shear-screw-mounted into the top of a J-slot top stinger (226) for a bridge plug (200, 201).

Fig. 10 is a sequence of drawings of a method using a bridge plug running tool (100) with a bridge plug (201) with a through bore (202) with a valve (203) in the through bore. a) run in hole and set bridge plug, open valve, pressure test integrity of plug from below. b) shut the valve (203), pull bridge plug running tool (100) off by shearing shear screws (118) in the connection to the J-slot top stinger (226). c) pull upwardly while circulating in cement slurry on top of the bridge plug and the J- slot top stinger (226)., d) wash out excess cement, let set and harden. e) dress off poor cement from top of set or hardened cement. f) weight load and tag top of dressed off cement plug. Verify cement plug. g) pull tool string out of hole.

Embodiments of the invention

The invention provides a drill pipe string conveyed bridge plug running tool (100) comprising, please see Fig. 1 and Fig. 2;

- an axially extending mandrel (1) with an upper connection (101) to a drill pipe string ( not shown) and provided with a through bore (102),

- said through bore (102) extending to a lower portion of said mandrel (1) and continued into a cylindrical sleeve-shaped stinger portion (103),

- said cylindrical sleeve-shaped stinger portion (103) further arranged for being releasably connected to a bridge plug (200) arranged for being set in a casing, please see Fig. 0, leftmost illustration,

- said cylindrical sleeve-shaped stinger portion (103) arranged for being released from said bridge plug (200), please see Fig. 0, second illustration, and for depositing cement on top of said bridge plug (200), please see Fig. 0, third illustration, and thus in said casing, - said mandrel (1) having two or more radially extending dress-cutter blades (108) arranged for dress-cutting into a top of said deposited, hardened cement, please see Fig. 0, fifth illustration,

- said dress-cutter blades (108) provided with two or more dress-cutter edges (182) extending radially beyond said cylindrical sleeve-shaped stinger portion (103) and arranged for cutting axially into the top of said cement when set and hardened,

- said dress-cutter blades (108) and said cylindrical sleeve-shaped stinger portion (103) arranged for tagging the resulting dressed cement surface, please see Fig. 0, sixth illustration.

The cylindrical sleeve-shaped stinger portion (103) may cut its way into the central, smaller area portion in the center of the deposited, hardened cement without further cutting elements, but in a further embodiment it may be provided with cutter elements, particularly in an embodiment a front cutter element (162) arranged transversely on the lower end of the cylindrical sleeve-shaped stinger portion (103), and arranged for efficiently dress-cutting and tagging into the central area of the deposited, hardened cement. It will still work as a cement stinger. The cylindrical sleeve-shaped stinger portion (103) further contributes to laterally stabilizing the dress-cutting blades (108) from lateral wobbling in the casing.

An advantage of having the outer diameter of the cementing cylindrical sleeveshaped stinger portion (103) adapted to fit inside the inner diameter of the J-slot top stinger (224) is that the diameter of the cementing cylindrical sleeve-shaped stinger portion (103) becomes significantly smaller than the diameter of the dress-cuter blades (108) which will allowed to make a plane, wide dressed surface of a top of the cement plug with only a comparatively small hole in the middle, thus providing a large plane surface available for tagging and mechanical pressure testing.

In other words, the bridge plug running tool (100) according to the invention is arranged for drill pipe string conveyed running in a bridge plug (200) into a well casing, the bridge plug running tool (100) comprising a cylindrical sleeve-shaped stinger portion (103) arranged for cementing, at its lower end, the cylindrical sleeve- shaped stinger portion (103) also arranged for being releasably connected into a central bore of the bridge plug (200), and dress-cutter blades (108) arranged about the base of the cylindrical sleeve-shaped stinger portion (103), the dress cutterblades (108) also used for tagging after dressing. In this way a bridge plug (200) may be set in the casing, disconnected by pulling up, cementing on top of the bridge plug (200), allowing the cement plug to set and harden, dress the top of the cement plug, and tag the dressed top to verify cement quality, all in one run.

In an embodiment of the invention said cylindrical sleeve-shaped stinger portion (103) is arranged for being connected into a main bore (224) of a J-slot top stinger (226) of said bridge plug (200).

The J-slot top stinger (226) is otherwise arranged for fitting into a J-slot sleeve of an ordinary DP conveyed J-slot plug running tool not used in this invention. A great advantage of this feature of being connectable to an ordinary J-slot top stinger (226) is the fact that one may use bridge plugs having a common type of J-slot top stinger which are usually and otherwise run in hole using a J-slot cylinder running tool. In an embodiment only a simple slotting of the J-slot top stinger (226) is required, a modification which is easily made by the on-site personnel or workshop personnel.

In an embodiment according to the invention said cutting edges (182) are generally axial-transverse to the tool axis so as for when dressing axially into said deposited cement plug forming a transverse, plane surface to be tagged, please see Fig. 0.

In an embodiment according to the invention the dress-cutter blades (108) are arranged for spanning a significant portion of an interior diameter of said casing, such as illustrated in Fig. 0. The dress cutter-blades (108) may be arranged for dress cutting out to a full casing bore radius and down to a depth in deposited cement plug of proper hardened cement quality.

In an embodiment according to the invention said cylindrical sleeve-shaped stinger portion (103) is provided with a transversely arranged front cutter blade (162) having a cutting width corresponding to an outside diameter of said cylindrical sleeveshaped stinger portion (103).

In an embodiment according to the invention said dress-cutter blades (108) have a part-helical shape about said mandrel (100). This may be done in order to increase rotational force bending resistance and to stabilize the rotation in the casing bore.

In an embodiment according to the invention said dress-cutter blades (108) have an axial-parallel directed, radial straight shape about said mandrel (1). This is shown in the attached drawings.

The dress-cutter blades (108) may in an embodiment be screwed onto the mandrel (1) as shown in the drawings. The dress-cutter blades (108) may in an embodiment be welded onto the mandrel (1) for providing ruggedness against rotational impact forces.

In an embodiment according to the invention, a slot (208) is formed for each of said dress-cutter blades (108), said slots (208) cut into the top of said J-slot top stinger. An advantage of this embodiment is that the slot edges transfer torque from the blades to the plug stinger and generally stabilize the plug during run-in.

Circulation sub

In an embodiment according to the invention illustrated in Fig. 1 , Fig. 2, Fig. 3, Fig.

4, and Fig. 6, a circulation sub (228) is arranged below said J-slot top stinger (226) of said bridge plug (200). An advantage of this embodiment of the invention, the circulation sub (228) allows circulating well fluid during the run-in of the bridge plug (200), particularly if the bridge plug (200) has no through bore, no ball valve, as opposite to some through bore plugs with a central bore valve through which one may circulate while running in.

Blind circulation sub In an embodiment as shown in Fig. 2, the circulation sub (228) is a blind circulation sub. This blind circulation sub is advantageous in that one may circulate in fluid through the drill pipe string bore and out through the blind circulation sub during run- in of the bridge plug (200) in order to facilitate running in. Further, with the circulation blind plug, one may circulate out debris about the J-slot top stinger (226) and the top of the bridge plug (200). This is useful when using a bridge plug (200) without a through bore.

No circulation sub

However, in an alternative embodiment there is no blind circulation sub on top of the bridge plug (200, 201). In an embodiment there is communication via the drill pipe string bore (102) and through the main bore (224) of the J-slot top stinger (226) and through the bridge plug (201), and a valve (227) in the J-slot top stinger (226) or a valve (203) in the bridge plug (201). The valve (203) may be in the top stinger (226), see Fig. 7, or the valve (203) may be in the bridge plug (201), see Fig. 8.

Valve in top stinger

In the embodiment wherein the valve (227) is part of the J-slot top stinger, please see Fig. 8, the J-slot top stinger (226) has a valve (227) and the bridge plug (201) has a through bore (202). This allows using a bridge plug (201) with a through bore (202) but without a ball valve or the like in the through bore (202) or through passage. The valve (227) may be operated to close or open by RH and LH rotation of the running tool (100) before pulling off the running tool (100) from the J-slot top stinger (226).

The bridge plug (200, 201) is provided with packer (212) for sealing the bridge plug annulus to the surrounding casing, and slips (211) for setting the bridge plug (200, 201) in the casing.

Valve in bridge plug (201). In another embodiment according to the invention the J-slot top stinger (226) has no valve, and the bridge plug (201) has a through bore (202) and a valve (203) in the through bore (202).

Bridge plug with ball valve

In an embodiment there is no circulation sub arranged below said J-slot top stinger (226), and said J-slot top stinger (226) is further connected to a bridge plug (201) with a valve (203) in a through bore (202), said valve (203) , such as a ball valve, is arranged for being open after said bridge plug (201) has been set, pressure test from below is conducted, and said valve (203) arranged for being closed before disconnecting said stinger (103) from said J-slot top stinger (226), and before cementing starts.

J-slot top stinger with valve, inexpensive plug

In an embodiment of the invention wherein no circulation sub is arranged below said J-slot top stinger (226), and said J-slot top stinger (226) is further connected to a bridge plug (201) with a through bore (202) , said J-slot top stinger (226) provided with a with a valve (227) in its through bore (224), said valve (227) arranged for being open after said bridge plug (201) has been set, pressure test from below is conducted, and said valve (227) arranged for being closed before disconnecting said stinger (103) from said J-slot top stinger (226), and before cementing starts.

In an embodiment of the invention there is arranged circulation ports (119) are arranged in said cementing stinger (103), said circulation ports (119) arranged for being covered by said J-slot top stinger (226) before said shear screws (118) are sheared, and for being uncovered when said shear screws (118) are sheared out by pulling off from the J-slot top stinger (226).

In an embodiment there are seal rings (120) on the cementing stinger (103) arranged above the circulation ports (119) The advantage is that the circulation ports (119) are closed when the running tool (100) is connected to the through-bore bridge plug (201) when setting and pressure testing, and opened after disconnection in order to allow lateral flushing while washing out or dressing or washing out after dressing.

Burst discs

In an embodiment according to the invention the bridge plug running tool (100) comprises one or more burst discs (140) arranged in a passage from said central bore (102) radially to an outside face of the tool mandrel.

The burst disc (140) is arranged to break in order to avoid exceeding an unintentional high pressure in the drill pipe string during pressure testing of a set bridge plug (201) before disconnecting from the bridge plug (201) or during circulating in fluids during cementing, washing out, dressing.

In another aspect according to the invention it is a method of forming and verifying a cement plug in a single run in a casing bore, the method comprising the steps of:

- assembling a bridge plug (200, 201) on a drill-pipe string conveyed through-bore bridge plug running tool (100),

- said bridge plug running tool (100) comprising a cementing stinger portion (103) releasably connected to an upper part of said bridge plug (200),

- said bridge plug running tool further comprising dress-cutting blades (108) arranged about a base of said cementing cylindrical sleeve-shaped stinger portion (103),

- running into a well said bridge plug (200) on said running tool (100) to a target depth,

- setting said bridge plug (200) in the casing, please see Fig. 0,

- pulling up on said drill pipe string and disconnect said cylindrical sleeve-shaped stinger portion (103) from said bridge plug (200),

- using said cylindrical sleeve-shaped stinger portion (103), circulating in cement slurry on top of said bridge plug (200) to form a cement plug in said casing, please also see Fig. 0,

- allowing said cement plug to set and harden,

- using said running tool (100) dressing a top of said cement plug, - using said running tool (100) tagging said dressed cement plug to verify its quality.

In a further embodiment according to the invention, after setting said bridge plug (201), wherein said bridge plug (201) has a through bore (202) and is provided with a valve (203), with said valve (203) held open and setting pressure in said drill pipe string to pressure test said set bridge plug (201) from below,

- closing said valve (203) before pulling up said cylindrical sleeve-shaped stinger portion (103) from said J-slot top stinger (226) on said bridge plug (201).

There may be arranged flushing ports (109) from the axial bore and having their mouths between the dress-cutter blades, please see Fig. 1. these flushing ports may be used for flushing out debris cut away during dressing.