Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B29/00—Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B29/00—Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
  • E21B29/002—Cutting, e.g. milling, a pipe with a cutter rotating along the circumference of the pipe
  • E21B29/005—Cutting, e.g. milling, a pipe with a cutter rotating along the circumference of the pipe with a radially-expansible cutter rotating inside the pipe, e.g. for cutting an annular window

Definitions

• the present invention relates to a device and a method for the slotting of casings.
• the device comprises a slotting tool and is provided for the longitudinal slotting of casings without completely separating or parting them in order to subsequently mill the previously slotted areas of the particular casing in order to remove in this manner the walls of the casing. Predetermined breaking points for metal cuttings during the milling process are made available by the longitudinal slotting. Slotting as used in the present invention is not to be understood to also comprise cutting into two parts or parting.
• the basic casing design for well bores is usually as follows: The outermost cemented casing is called surface casing. The other casings are placed into the latter. The completion, which serves as the production pipe, is located innermost. Individual pipes are connected to a pipe string. These casings are usually cemented into the well bore - at least after a certain depth - and cannot be readily removed by cutting and pulling.
• the casings are cemented into the well bore, it is necessary to remove the casings from above by milling.
• the removal of the casings is also called complete liquidation.
• the innermost casing is milled to the desired depth with the aid of a milling device and the chipped material is removed. Subsequently, the casing which is the nearest from the inside to the outside is successively milled to the desired depth with the milling device.
• the technical casings do not necessarily have to be cemented up to the surface.
• the milling of long casing sections is a standard type of work.
• the composition of fluids and the composition of the solids separation system are necessary.
• the use of cutting separation systems has proven itself.
• cleaning work on that system which has a high cost for time and personnel, is minimized.
• the invention is concerned with the problem of making available a method for the milling of casings which reduces and prevents the initially cited problem of the formation of metal cutting nests and/or the adhesion of chips to the milling head or to the work string.
• the chips should be conditioned in such a manner that they are effectively removed by the mud.
• the problem is solved in detail by a method which comprises a longitudinal slotting of a casing with a slotting tool for the creation of predetermined breaking points and by a corresponding device.
• the method comprises a subsequent removal by milling of the previously slotted pipe walls. Problems associated with the formation of long twisted and/or curled metal cuttings are minimized due to the slotting.
• the device used for the slotting of the casing comprises a slotting tool with a base body whose outside diameter is smaller than the inside diameter of the casing, and at least three slotting devices arranged in a staggered manner over the circumference of the base body and with outwardly directed slotting edges for the introduction of longitudinal recesses, i.e.
• the slots have in particular slot depths of 5 to 95% of the wall thickness of the casing, especially preferably 30 to 60% of the wall thickness in average over the length of path.
• the negatively acting formation of long cuttings and chip nests can be prevented in that the pipe walls to be milled are at first slotted with a slotting tool longitudinally, i.e. in the longitudinal direction of the pipe axis, and subsequently the slotted pipe walls are milled.
• the slotting of the pipe wall produces defined longitudinal recesses in the form of slots in the inner, metal wall of the particular casing.
• the slotting consists in a local reduction of the wall thickness of the casing along the longitudinal direction of the casing.
• the distinguishing characteristic of the slotting is that the pipe is not separated and its integrity necessary for the milling process should be retained.
• the casing is slotted over the length to be removed.
• Casings are preferably slotted which are cemented in.
• the reduction of the wall thickness is subsequently also designated as the slot depth.
• the preferred slot depth is influenced, e.g., by the material properties of the casing such as, in particular the yield strength, the wall thickness and the composition of the metal material.
• the slots are characterized in that they constitute a max- imum of 95% of the wall thickness.
• Preferred slot depths are 5 to 95% of the wall thickness, especially 30 to 60% of the wall thickness (in average over the length of the slotting path).
• These slots form a type of predetermined breaking point (preferably at regular inter- vals) in order to form milling chips during the milling operation.
• These predetermined breaking points ensure that the millings have a defined length which is as long as the distance between two slots along the pipe wall. The length of the millings is selected in such a manner that the millings formed are no longer trapped on the rotating work string and can be removed from the borehole by traditional techniques such as, for example, by circulating Drilling mud.
• the slotting tool consists of a base body whose outside diameter is smaller than the inside diameter of the casing to be milled in order to be able to be completely introduced into the particular casing. Therefore, the slotting tool and the casing form a pair because the slotting tool is inserted in a manner which fits the particular casing.
• the slotting tool comprises several slotting devices which are arranged on the base body of the slotting tool, which base body is cylindrical as a rule.
• the slotting devices project from the base body so that the plurality of the slotting edges, preferably all slotting edges, extend into the material of the casing.
• At least three, preferably at least 4, and at the most 12, preferably up to 8 slotting devices are provided on the slotting tool which are preferably distributed approximately uniformly over the circumference.
• the slotting edges of the slotting devices preferably run to a point on their ends.
• the slotting edges for opposing pairs i.e., an imaginary connection of the slotting edges of a pair, approximately intersects the center of the casing.
• the slotting edges of adjacent slotting devices can be arranged offset to each other in the direction of slotting.
• the outside diameter of the slotting edges or as a result thereof the penetration depth of the slotting edges increases from front to back in the slot direction, e.g. in the form of stairs.
• the edges preferably run to a point with a flat section in the direction of slotting and preferably also counter to the direction of slotting.
• “Front” means in this sense in the direction of the movement of the slotting tool, e.g. : "front” means "down” for a downwardly directed pressure.
• the slotting devices are constructed partially or in their totality as slotted disks.
• the slotted disks are rotatably supported in the base body and comprise slotting edges running to a point on their outer circumference.
• the base body of the slotting tool preferably has a circular shape in its cross section.
• a guide section is preferably provided in front in the slotting direction on the slotting tool, which guide section is constructed according to an embodiment as a guide pin and is preferably conically tapered in order to correspond to the rear to the slotting devices approximately to the caliber of the casing, and is preferably 2 to 10% smaller than the inside diameter of the casing in order to guide the slotting tool in a centered manner in the casing.
• the slotting takes place according to one embodiment under pressure from above downward and according to another embodiment under pulling from below upward. Slotting devices with static slotting edges are always guided from above downward while being pressed into the casing. Slotting devices with static slotting edges are not suitable for a slotting during pulling the work string upwards because the slotting device must first be lowered substantially without resistance to a certain depth with the slotting to start afterwards. To these end slotting devices with extendable slotting edges are required.
• a slotting device with extendable slotting edges comprises, according to one em- bodiment, a hydraulic system with which the slotting edges can be extended. It is also possible that the slotting edges are arranged on several movable plates of the base body, which can be extended.
• the slotting edges and/or the plates are not extended hydrau- lically but rather only by the force of traction or of pressure, for example in that the slotted edges run in a track whose first end position holds the slotting edge at a distance from the casing and whose opposite, second position guides the slotting edges onto the casing.
• the first position is in front in the direction of cutting and the second position is in the rear in the cutting direction.
• the slotting device is part of the milling device, so that the milling head and the slotting device form a combined tool.
• the rotating milling head and the slotting device are decoupled as regards the rotation necessary for the milling because the slotting device is rotatably supported on a shaft. Therefore, a longitudinal slotting in the direction of the pipe axis is brought about before the milling head mills the casing area which is then slotted.
• the advantage of the integration of the slotting device and of the milling device in one combined tool is that only one tool has to be moved through the casing and the slotting and the milling take place in one work step.
• the slotting device is exposed to a great stress by material and becomes worn, whereupon it must be moved out of the borehole in order to be replaced. If the milling head and the slotting device are one unit, this applies to the entire unit.
• the slotting device is introduced into the casing on a work string. This is as a rule the drill pipe, which is not put in rotation solely for the slotting device but is put in rotation for the combination tool consisting of the slotting device and the milling device.
• the pressure force exerted on the slotting device is generated by the weight of the drill pipe.
• the guide pin preferably runs in the direction of movement of the slotting tool in a conical manner.
• the guide pin is constructed in the form of a centering basket, e.g., in the form of one or more brackets.
• Fig. 1 and fig. 2 show a slotting device with a guide pin and several fixed slotting devices which project like wings from the base body and which are attached parallel to the advance direction on the circumferential surface of the base body.
• Fig. 3 and fig. 4 show a slotting device with a guide pin and several disk shaped, rotatable slotting devices.
• Fig. 5 and fig. 6 show, similar to fig. 2 and 3, a slotting device and several disk- shaped, rotatable slotting devices which are, however, arranged successively in a line and cut deeper into the casing to be slotted in a stepped manner.
• Fig. 7 and fig. 8 show another embodiment of the slotting device with the guide pin, centering basket and several wing-shaped slotting devices which can be extended in the base body and which can be moved out of the base body by the action of a vertically directed force. In case of a movement under pulling the centering pin is preferably shaped as a centering basket.
• Fig. 9 and 10 show a slotting tool with a centering basket and several extendable, disk-shaped slotting devices projecting from the base body which are arranged vertically on a plane on the circumference of the non-rotating base body, wherein the extendable, disk-shaped slotted devices are at first moved into the base body and then moved out.
• Fig. 1 1 and 12 show a combined device for the slotting and milling in one work step for the pressure-loaded movement of the combined tool from above downward before the introduction into the casing to be slotted.
• Fig. 13 and 14 shows mechanical extension mechanisms for the slotting devices; and
• Fig. 15 and 1 6 show a hydraulic extension mechanism in which the slotting devices are extended by a hydraulic liquid.
• Fig. 1 shows an embodiment of the slotting device before the introduction into the casing (4) to be slotted and comprising a non-rotating base body (5), a guide pin (6) and several fixed, wing-like slotting devices (7) which are attached vertically, i.e. parallel to the direction of advance on the circumferential surface of the non-rotating base body (5).
• the base body (5) is carried by a drill pipe (1 ).
• the drill pipe (1 ) drives the slotting device in the direction of slotting into the borehole with the guide pin in front.
• the drill pipe (1 ) itself is not rotated.
• the conically tapering guide pin (6) is located in front on the base body.
• the casing (4) to be slotted is cemented into the outer casing (2).
• the figure shows in a corresponding manner the cement (3) between the casings (2) and (4).
• the upper, inner casing had already been removed, e.g., in that it had been sectioned above the cement head and pulled out.
• the pipe shown as the outer casing (2) does not necessarily have to be the surface casing but rather can also be another casing.
• Figure 2 shows the slotting device of the invention according to fig. 1 wherein the slotting device has already advanced along a section of the casing (4) to be slotted and slot-like recesses (8) along the inner surface of the casing (4) were produced by pressing in the slotting edges of the slotting device and moving the device in the direction from above downwards.
• Fig. 3 shows an embodiment of the slotting device before the introduction into the casing (4) to be slotted and comprising a non-rotating base body (5), a guide pin (6) and several fixed, wing-like and rotatable slotting devices (9) which are attached on the circumferential surface of the non-rotating base body (5) so that the opposing slotting edges penetrate uniformly into the casing.
• the base body (5) in fig. 3 is shown broken into sections for the graphic display of one of the disk-like slotting devices.
• Figure 4 shows the slotting device of the invention according to fig. 3 wherein the slotting device has already advanced along a section of the casing (4) to be slotted and slot-like recesses (8) along the inner surface of the casing (4) were produced by pressing in the slotting edges of the slotting device device and moving the device in the direction from above downwards.
• Fig. 5 shows another embodiment of the slotting device before the introduction into the casing (4) to be slotted and furthermore comprising several disk -like and rotat- able slotting devices (9) which are attached vertically on a plane along the surface of the non-rotating base body (5), wherein 3 of the disk-like, rotatable slotting devices (9) are arranged at a distance from each other on a line and the distance of opposing slotting edges of the slotting device (9) decreases from above downward.
• Figure 6 shows the slotting device of the invention according to fig. 5 wherein the casing (4) to be slotted already has a length section into which the slotting device was driven and slot-like recesses (8) along the inner surface of the casing (4) produced by pressing in the slotting edges of the slotting device from above downward, wherein the depth of the slot increases step-by-step from below upward from slotting device (9) to slotting device (9) so that each slotting edge creates only a part of the total depth of the slot and therefore the stress on the individual slotting device (9) is minimized.
• Fig. 7 shows a slotting device according to the invention inside the casing to be slotted (4), comprising a non-rotating base body (1 1 ) with a guide pin (6), centering basket (10) and several wing-like slotting devices (12) which can be extended in the base body (1 1 ) and which are arranged vertically on a plane on the circumference of the base body (1 1 ), wherein the extendable, wing-like slotting devices (12) were moved into the base body.
• Figure 8 shows the other embodiment of the slotting device according to fig.
• the operation of "pulling” allows the introduction of greater forces via the drill pipe (1 ) in the direction of slotting.
• the centering pin is prefer- ably shaped as a centering basket.
• another centering basket (10) can be arranged on the bottom on the base body (not shown).
• Fig. 9 shows another embodiment of the slotting device according to the invention inside the casing to be slotted (4), comprising a non-rotating base body (1 1 ) with a guide pin (6), centering basket (10) and several wing-like slotting devices (12) which can be extended in the base body (1 1 ) and which are arranged vertically on a plane on the circumference of the non-rotating base body (1 1 ), wherein the extendable, disk-like slotting devices (12) were moved into the base body.
• Figure 10 shows the slotting device according to fig.
• Fig. 1 1 shows a combined device for the slotting and milling in one work step for the pressure-loaded movement of the combined tool from above downward before the introduction into the casing (4) to be slotted.
• the combined tool comprises an upper rotating base body driven by the drill pipe for the milling (15) and a non-rotating base body (5) attached underneath it and decoupled by a bearing and for the slotting.
• the non-rotating base body (5) for the slotting comprises, in a manner similar to fig. 1 , several fixed, wing-like slotting devices (7), which are vertically arranged along the circumference of the non-rotating base body (5).
• the base body (5) is provided with a guide pin (6) for the slotting.
• FIG. 12 shows the combined tool according to fig. 1 1 , wherein the fixed, wing-like slotting devices (7) have already been moved into the casing (4) and slot-like recesses (8) have been created along the inner surface of the casing (4) by pressing the slotting device from above downward, and the wing-like milling devices with the particular lowermost cutting element (1 6) of each wing have been set on the casing and mill the casing in a chip-removing manner due to the rotary movement.
• the chips being produced accumulate on account of the previously created, slot-like predetermined breaking points in the form of chips with a limited length. These chips can be advantageously removed with known fluid circulation techniques.
• the milling mud is conducted through the drill pipe and exits at the lower end of the base body, e.g. through nozzle openings in the centering pin. The formation of chip nests is eliminated or is minimized.
• a mechanical extending mechanism is shown in figures 13 and 14.
• An upwardly tapering cone inside the base body is moved mechanically upward, e.g. by the reversing of the movement from the lowering of the cutting tool to pulling it up.
• the slotting devices are forced outward along an oblique plane to a stop position (fig. 14) and the slotting devices engage into the casing up to a slotting depth (but not cutting).
• a rotatable slotting device (9) is shown on the right of the snaking line and to the left a fixed, wing-like slotting device (7) is shown.
• the upward movement for moving the slotting devices out or in is limited upward and downward by a "J slot" which can be locked in the particular upper or lower end positions by a rotary movement of the drill pipe.
• the J-shaped slot profile in a jacket creates a stretch for a control cam on a shaft running in the jacket. Two work positions are defined by moving the control cam up or down and engaging it by a rotary movement.
• Figures 15 and 1 6 show a hydraulic extension mechanism in which at least two opposite slotting devices, preferably all slotting devices, are simultaneously extended by loading a hydraulic liquid by pressure in a pressure cylinder.
• the liquid in the bore rod is loaded above the surface with pressure.
• the tool is hydraulically connected to the drill string so that an applied pressure moves the cylinder pistons and moves the slotting devices out (Fig. 1 6) as long as the cylinder pistons are loaded with pressure.
• the hydraulic pressure can be built up by the mud in that the mud pumps generate a sufficiently great inner pressure relative to the outer pressure.
• the hydraulic liquid and the mud can be separated by two pressure containers located in an exchange.
• non-rotating base body with an inner device for extending a wing-like slotting device
• non-rotating base body with an inner device for extending a disk-like, rotatable slotting device

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)

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• 2016
  • 2016-02-26 DE DE102016103507.6A patent/DE102016103507A1/de not_active Ceased
• 2017
  • 2017-02-24 WO PCT/EP2017/054426 patent/WO2017144712A1/en active Application Filing
  • 2017-02-24 EP EP17707309.5A patent/EP3420178B1/de active Active

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