US20010047884A1 - Directional drilling apparatus and method utilising eccentric stabiliser - Google Patents
Directional drilling apparatus and method utilising eccentric stabiliser Download PDFInfo
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- US20010047884A1 US20010047884A1 US09/202,342 US20234298A US2001047884A1 US 20010047884 A1 US20010047884 A1 US 20010047884A1 US 20234298 A US20234298 A US 20234298A US 2001047884 A1 US2001047884 A1 US 2001047884A1
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- stabiliser
- mass
- bore
- mandrel
- rotating
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- 239000003381 stabilizer Substances 0.000 title claims abstract description 63
- 238000005553 drilling Methods 0.000 title claims abstract description 43
- 238000000034 method Methods 0.000 title claims description 9
- 239000012530 fluid Substances 0.000 claims description 16
- 230000000694 effects Effects 0.000 description 2
- 241001233242 Lontra Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
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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
- E21B7/00—Special methods or apparatus for drilling
- E21B7/04—Directional drilling
- E21B7/06—Deflecting the direction of boreholes
- E21B7/062—Deflecting the direction of boreholes the tool shaft rotating inside a non-rotating guide travelling with the shaft
-
- 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
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
- E21B17/1014—Flexible or expansible centering means, e.g. with pistons pressing against the wall of the well
Definitions
- This invention relates to drilling apparatus, and in particular to apparatus for use in directional drilling and a directional drilling method.
- the vertical inclination and azimuth of a drilled bore may be controlled such that the bore may extend from the surface to a target area which is not vertically aligned with the point on the surface where drilling commences. This permits a wide area to be accessed from a single drilling location and is therefore particularly useful in offshore drilling operations.
- Rotation of the drill bit mounted on the lower end of the drill string is achieved bv rotation of the entire drill string, by a turntable on the surface, and often also by a downhole motor located on the drill string adjacent the bit.
- the downhole motor is usually driven by the drilling fluid which is pumped through the string.
- Steerable downhole motors include a “bent” housing or elbow which introduces a small deviation (around 1°) in the end portion of the drill string. When the entire string is rotating such an elbow has little or no effect on the bore trajectory. However, if the string is stopped and then adjusted such that the motor bend is in a desired direction, rotating the drill bit using only the downhole motor will result in the trajectory of the well deviating.
- Drilling in this manner without rotation of the drill string may be very time consuming as static friction between the non-rotating parts of the string and the bore wall tends to produce a stick-slip progression of the string through the bore. This results in sudden increases in the weight (downward force) being applied to the bit and motor, causing the motor co stall. The drill string must then be picked off bottom before drilling may restart. This problem may even result in it becoming impossible to drill any further without rotating the drill string and is particularly acute in horizontal and extended reach wells.
- directional drilling apparatus for location on a drill string, the apparatus comprising:
- a stabiliser having a mandrel for connection to the drill string and an eccentric non-rotating element mounted on the mandrel for offsecting the string in the bore;
- orientation control means operativelv associated with the non-rotazing element and including a non-rotating offset mass for maintaining said element at a selected orientation relative to the bore as the drill string rotates therein.
- the invention permits the drill string to be rotated while the bore trajectorv is controlled or adjusted.
- the stabiliser is of a larger gauge than the non-rotating otfset mass. Accordingly, the non-rotating offset mass is held clear of the bore wall and depends from the string.
- the stabiliser is preferably of the same gauge as the bore or is of slightly smaller gauge than the bore.
- the orientation control means includes a mandrel for connection to the drill string with the offset mass being rotatable on the mandrel, the mass being connectable to the eccentric stabiliser element.
- the mass may be fixed relative to the eccentric stabiliser element such tnat the element may only assume a single orientation within a bore.
- the eccentric stabiliser element may be positioned in one of two orientations relative to the of fset mass, to turn the bore to the “left” or “right” if such an apparatus is provided in conjunction with a conventional adjustable stabiliser the driller mav utilise the apparatus to control the bore azimuth and the stabiliser to control the bore inclination.
- the mass may be disengaged from the stabil 4 ser element to permi the relative positions thereof to be varied as desired, and thus vary the orientation of the scabiliser relative to the bore and permit drilling of a bore of varying inclination and azimuth solely by means oe the apparatus.
- disengagement and re-engagement of the mass and stabiliser element may be executed remotely, from the surface, to avoid the requirement to retract the drill string from the bore.
- a clutch is provided between the mass and stabiliser element and may be disengaged by, for example, picking up the drill string.
- the clutch preferably has a locked configuration to prevent accidental disengagement. Locking and unlocking may be accomplished by any suitable means, including a drilling fluid actuated latch.
- the clutch includes means for connecting the mandrel relative to the non-rotating stabiliser element and which operates on the clutch disengaging. This permits the eccentric element to be rotated to a desired orientation by rotation of the string. On the clutch re-engaging the connecting means disengages the element from the mandrel.
- the non-rotating eccentric element may be a cam for location between the mandrel and an outer stabiliser body including extendible bearing elements including cam follower portions; as the mandrel and outer body rotate in the bore relative to tne non-rotating cam, the bearing elements are extended and retracted by the cam.
- the non-rotating element may be an eccentric stabIliser body.
- a further stabiliser is provided on the strina above the eccentric stabilser.
- FIG. 1 shows the lower end of a drill string provided with directional drilling apparatus in accordance with a first embodiment of the present invention
- FIG. 2 corresponds to FIG. 1, but shows the drilling apparatus in section
- FIG. 3 is an enlarged sectional view of the drilling apoaratus of FIG. 1;
- FIGS. 4 and 5 correspond to FIG. 2, and illustrate a clutch assembly of the apparatus engaged and disengaged, respectively;
- FIGS. 6 and 7 are enlarged views of the clutch assembly of the drilling apparatus and correspond to the circled areas 6 and 7 of FIGS. 4 and 5, respectively;
- FIG. 8 shows the lower end of a drill string provided with directional drilling apparatus in accordance with a second embodiment of the present invention
- FIG. 9 corresponds to FIG. 8, but shows the drilling apparatus in section
- FIG. 10 is an enlarged sectional view of the drilling apparatus of FIG. 9;
- FIGS. 11 and 12 correspond to FIG. 9, and illustrate a clutch assemblv of the apparatus engaged and disengaged, respectively;
- FIGS. 13 and 14 are enlarged views of the clutch assembly of the drilling apparatus and corresponding to the circled areas 13 and 14 of FIGS. 11 and 12, respectively.
- FIG. 1 of the drawings illustrates the lower end of a drill string 20 located within a drilled bore 22 .
- the string 20 includes a stabiliser 24 , drilling apparatus in accordance with a first embodiment of the present invention in the form of a rotary steerable tool assembly 26 , and a drill bit 28 joined to the tool assembly 26 by a connecting sub 30 .
- the tool assembly 26 comprises a stabiliser 32 and a nonrotating offset mass 34 .
- FIG. 2 of the drawings illustrates the tool assembly 26 in section. The main features and operation of the tool assembly 26 will be described initially, followed by a more detailed description of the individual elements of the assembly 26 .
- the offset mass 34 of the tool assembly 26 defines an offset bore 36 through which a tubular mandrel 38 extends.
- the mass 34 is free to rotate on the mandrel 38 and thus tends to remain in the same orientation while the drill string 20 , and thus the mandrel 38 , is rotated within the bore 22 ; the tool assembly 26 will only operate in inclined well bores, where the offset mass 34 will position itself to the lower side of the well bore.
- the mass 34 is formed of steel and is approximately 4.6 m (15 feet) long and has a mass of 1000 kg (2,200 lbs).
- the mass is arranged such that if s centre of gravity is offset from the mandrel axis by 4.83 cm (1.90 inches), producing a resistive torque of approximately 48 Nm (400 ftlbs).
- the mandrel 38 also extends through the stabiliser 32 and is connected to an annular stabiliser body 40 which defines, in this example, three helical blades 42 (see FIG. 1), each of which accommodates a series of oistons which may be radially extended from the blades 42 .
- the inner end portions of the pistons 44 engage a non-rotating element in the form of a cam 46 which is normally coupled, via a clutch assembly 48 , to the offset mass 34 . Accordingly, as the drill string 20 is rotated, the offset mass 34 and cam 46 remains substantially stationary within the bore, the high spot on the cam 46 forcing the stabiliser pistons 44 outwardly against the bore wall with each revolution of the string 20 . In the illustrated example the pistons 44 will be pushed outwardly into contact with the right hand side of the bore, pushing the drill bit 28 , and thus the trajectory of the bore, to the left.
- the stabiliser 24 is connected by way of a threaded connection to a top sub 50 of the tool assembly 26 .
- the top sub 50 provides an entry for drilling fluid into the tool assembly and accommodates a fluid actuated latch assembly 52 which is used to maintain the clutch assembly 48 in the engaged or disengaged configuration;
- FIG. 3 illustrates the latch assembly 52 maintaining the clutch 48 in the disengaged configuration.
- the latch assembly 52 includes a lock tube 54 which is axially slidable within the top sub 50 and defines a venturi 55 towards its upper end.
- the lock tube 54 is biassed upwardly by a coil spring 58 , a guide ring 60 retaining the lower end of the spring 58 relative to a cartridge case 6 l between the tube 54 and the sub bore wall.
- Fixed centrally within the top sub 50 and above the cartridge case 61 is an obstructor member or rocket 62 , the lower end of which co-operates with the venturi 56 to limit the flow area through the top sub 50 .
- the interaction of the rocket 62 and the venturi 56 allows the configuration of the latch assembly 52 to be monitored from the surface: in the configuration shown in FIG.
- the lower end of the rocket 62 is spaced from the venturi 56 , such that the pressure drop across the venturi 56 is relatively low; however, in the position shown in FIG. 4 of the drawings, the rocket 62 extends through the venturi 56 , restricting the flow area and creating an additional back pressure which may be detected at surface.
- the spring 58 lifts the lower end of the lock tube 54 free of a double acting latch 64 , thus permitting movement of a collet 66 from one side of the latch 64 to the other; the collet 66 is fluted and spring tensioned such that it may be deflected inwardly to travel over the latch 64 .
- the collet 66 is threaded to the upper end of the mandrel 38 and slides within a colet support sleeve 68 which extends through the lower end of the top sub 50 .
- a tubular shroud 69 below the sleeve 68 extends into an outer sleeve 70 connected to the top sub 50 by threaded connection 72 .
- the sleeve 70 is splined to the mandrel 38 to prevent relative rotation thereof.
- mud pressure is compensated for at the upper end of the mandrel by a compensation ring 74 which is movable in an annular chamber 71 formed between the shroud 69 and the sleeve 70 .
- the lower portion of the chamber 71 is filled with oil via a sleeve port 76 .
- External drilling fluid is permitted to pass through the outer sleeve 70 into the upper portion of the chamber 71 via a port 78 on the opposite side of the compensation ring 74 from the oil fill port 76 .
- the mud pressure on either side of the mandrel 38 and the shroud 69 may thus be balanced to allow easier movement of the mandrel 38 .
- the mandrel 38 extends through the offset mass 34 and the stabiliser 32 , the lower end of the mandrel being connected by way of a threaded connection 80 to the rotating stabiliser body 40 .
- the pistons 44 mounted within the body blades 42 are mounted on roller bearings 82 which transfer the lateral movement produced by the offset is cam 46 to the pistons 44 .
- Three sets of bearings 84 perm 4 it rotation of the mandrel 38 and stabiliser body 40 relative to the cam 46 .
- the upper end of the cam 46 extends above the stabiliser body 40 and is connected to a flange 86 with a toothed face 87 forming the lower portion of the clutch assembly 48 .
- the upper portion of the clutch assembly 48 is formed by a corresponding flange 88 with a toothed face 89 provided on a lower end of the offset mass 34 .
- the clutch assembly 48 With the clutch assembly 48 engaged the cam 46 is rotationally fixed relative to the ofset mass 34 . However, with the clutch assembly 48 released, the cam 46 is free to rotate relative to the mass 34 . Further, as illustrated in FIGS. 6 and 7 of the drawings, the clutch assembly 48 is arranged such that, when disengaged, the cam 46 is rotationally fixed relative to the mandrel 38 . This is achieved by mounting a leaf spring 90 in a slot 92 in the mandrel 38 at the clutch assembly 48 .
- a pin 94 is provided on the free end of the spring 90 and with the clutch engaged contact between a raised portion of the spring 96 and the inner wall of the upper flange 88 pushes the pin 94 into a recess 98 formed in the mandrel 38 .
- the clutch 48 is disengaged, and the mandrel 38 moves downwardly relative to the upper clutch face 89 , the raised portion 96 moves into the gap between the faces 87 , 89 and the outer end of the pin moves into a recess 100 provided in the flange 86 . This has the effect of connecting the flange 86 and thus the cam 46 to the mandrel 38 such that rotation of the mandrel 38 results in corresponding rotation of the cam 46 .
- the drill string 20 is rotated in the bore 22 with the drill bit 28 in contact with the cutting face.
- Drilling fluid is pumped through the string 20 from the surface, the fluid exiting through nozzles in the bit 28 (shown as 101 in FIG. 2), and then carrying rock fragments from the cutting face up through the annulus between the string 20 and bore 22 .
- the clutch assembly 48 is engaged such that the offset mass 34 and the cam 46 are connected and remain stationary as the string 20 and the remainder of the tool assembly 26 rotate.
- the offset mass 34 locates itself on the lower side of the inclined bore and such that the high point on the cam 46 remains at the desired orientation within the bore 22 , causing the pistons 44 to be extended as they pass over the high point, and tending to deflect the bit 28 towards the opposite side of the bore.
- the pumping rate of the drilling fluid is reduced sufficientlv to allow the spring 58 to push the lock tube 54 upwardly, clear of the latch 64 .
- Tf the string 20 is then lifted from bottom, the top sub 50 , latch assembly 52 , outer sleeve 70 and offset mass 34 are raised relative to the mandrel 38 .
- the weight of the mandrel 38 , the stabiliser 32 and the drill bit 28 pull the collet 66 downwards over the latch 64 . If the drilling fluid flow rate is then increased once more, the lock tube 54 is pushed downwards and locks the collet 66 on the lower side of the latch 64 as illustrated, For example, in FIGS. 2 and 5.
- the drilling fluid flow rate is reduced once more, such that the lock tube 54 moves upwardly, out of engagement with the collet 66 . If weight is applied to the string 20 , the collet 66 will then ride over the latch 64 to re-engage the clutch 48 , and disengage the pin 94 from the flange 86 such that the cam 46 is again free to rotate relative to the mandrel 38 . If the drillirn fluid flow rate is increased once more the lock tube 54 moves down to locks the collet 66 in the latch 64 , and drilling may then continue.
- FIGS. 8 through 14 of the drawings illustrate directional drilling apparatus in accordance with a second embodiment of the preferred invention.
- the second embodiment shares a number of features with the first described embodiment, and these common features will not be described aaain in detail, and will be accorded the same reference numerals as were used when describing the first embodiment.
- the principal difference between the embodiments lie in the rotary steerable cool assembly 126 , and more particularly in the eccentric or offset stabiliser 132 .
- the stabiliser 132 is provided with an eccentric or offset stabiliser body 140 which is normally rotatable on the mandrel 138 .
- the stabiliser body 140 remains stationary as the string 20 is rotated. The trajectory of the bore is thus determined by the orientation of the stabiliser body 140 .
- the orientation of the stabiliser body 140 is changed in a similar manner to the cam 46 as described above in the first embodiment, that is by configuring the latch assembly 52 to allow disengagement of the clutch 148 and to couple the stabiliser body 140 to the mandrel 138 to allow the orientation of the body 140 to be altered relative to the offset mass 34 .
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Abstract
Description
- This invention relates to drilling apparatus, and in particular to apparatus for use in directional drilling and a directional drilling method.
- In directional or controlled trajectory drilling, the vertical inclination and azimuth of a drilled bore may be controlled such that the bore may extend from the surface to a target area which is not vertically aligned with the point on the surface where drilling commences. This permits a wide area to be accessed from a single drilling location and is therefore particularly useful in offshore drilling operations.
- Rotation of the drill bit mounted on the lower end of the drill string is achieved bv rotation of the entire drill string, by a turntable on the surface, and often also by a downhole motor located on the drill string adjacent the bit. The downhole motor is usually driven by the drilling fluid which is pumped through the string. Steerable downhole motors include a “bent” housing or elbow which introduces a small deviation (around 1°) in the end portion of the drill string. When the entire string is rotating such an elbow has little or no effect on the bore trajectory. However, if the string is stopped and then adjusted such that the motor bend is in a desired direction, rotating the drill bit using only the downhole motor will result in the trajectory of the well deviating. Drilling in this manner without rotation of the drill string may be very time consuming as static friction between the non-rotating parts of the string and the bore wall tends to produce a stick-slip progression of the string through the bore. This results in sudden increases in the weight (downward force) being applied to the bit and motor, causing the motor co stall. The drill string must then be picked off bottom before drilling may restart. This problem may even result in it becoming impossible to drill any further without rotating the drill string and is particularly acute in horizontal and extended reach wells.
- Attempts have been made to provide drilling apparatus which will permit bore trajectory to be varied or controlled while still rotating the drill string, primarily by providing a non-rotating eccentric mass on the drill string adjacent the drill bit, and which mass engages the “low” portion ao the bore wall and supports the drill string. A radially extending blade is mounted on the mass and engages the bore to produce a lateral force on the drill string causing the drill bit to deviate from its existing path, or at least prevents further deviation in the direction oa the blade. However, the success of such apparatus has been limited as the mass provides an unstable support for the heavy drill string, such that the mass is likely to topple and be moved to one side by the string, which will tend to move downwards to occupy the lower part of the bore. Examples of such arrangements are illustrated in U.S. Pat. Nos. 4,638,873 and 4,220,213.
- Other forms of directional drilling apdaratus for controlling hole direction or inclination by providing eccentric or offset blades or members are described in U.S. Pat. Nos. 3,062,303, 3,092,188, 3,650,338, 3,825,081 and 5 4,305,474.
- It is among the objectives of the embodiments of the present invention to provide directional drilling apparatus utilising an offset or eccentric mass which obviates or mitigates the disadvantages of the prior art arrangements.
- According to the present invention there is provided directional drilling apparatus for location on a drill string, the apparatus comprising:
- a stabiliser having a mandrel for connection to the drill string and an eccentric non-rotating element mounted on the mandrel for offsecting the string in the bore; and
- orientation control means operativelv associated with the non-rotazing element and including a non-rotating offset mass for maintaining said element at a selected orientation relative to the bore as the drill string rotates therein.
- In use, the invention permits the drill string to be rotated while the bore trajectorv is controlled or adjusted.
- Preferably, the stabiliser is of a larger gauge than the non-rotating otfset mass. Accordingly, the non-rotating offset mass is held clear of the bore wall and depends from the string. The stabiliser is preferably of the same gauge as the bore or is of slightly smaller gauge than the bore.
- Preferably, the orientation control means includes a mandrel for connection to the drill string with the offset mass being rotatable on the mandrel, the mass being connectable to the eccentric stabiliser element. In one embodiment, the mass may be fixed relative to the eccentric stabiliser element such tnat the element may only assume a single orientation within a bore. :n another embodiment, the eccentric stabiliser element may be positioned in one of two orientations relative to the of fset mass, to turn the bore to the “left” or “right” if such an apparatus is provided in conjunction with a conventional adjustable stabiliser the driller mav utilise the apparatus to control the bore azimuth and the stabiliser to control the bore inclination. In the preferred embodiment, the mass may be disengaged from the stabil4ser element to permi the relative positions thereof to be varied as desired, and thus vary the orientation of the scabiliser relative to the bore and permit drilling of a bore of varying inclination and azimuth solely by means oe the apparatus.
- It is Preferred that disengagement and re-engagement of the mass and stabiliser element may be executed remotely, from the surface, to avoid the requirement to retract the drill string from the bore. In one embodiment a clutch is provided between the mass and stabiliser element and may be disengaged by, for example, picking up the drill string. The clutch preferably has a locked configuration to prevent accidental disengagement. Locking and unlocking may be accomplished by any suitable means, including a drilling fluid actuated latch. Preferably, the clutch includes means for connecting the mandrel relative to the non-rotating stabiliser element and which operates on the clutch disengaging. This permits the eccentric element to be rotated to a desired orientation by rotation of the string. On the clutch re-engaging the connecting means disengages the element from the mandrel.
- The non-rotating eccentric element may be a cam for location between the mandrel and an outer stabiliser body including extendible bearing elements including cam follower portions; as the mandrel and outer body rotate in the bore relative to tne non-rotating cam, the bearing elements are extended and retracted by the cam. Alternatively, the non-rotating element may be an eccentric stabIliser body.
- Preferably also, a further stabiliser is provided on the strina above the eccentric stabilser.
- This and otter aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
- FIG. 1 shows the lower end of a drill string provided with directional drilling apparatus in accordance with a first embodiment of the present invention;
- FIG. 2 corresponds to FIG. 1, but shows the drilling apparatus in section;
- FIG. 3 is an enlarged sectional view of the drilling apoaratus of FIG. 1;
- FIGS. 4 and 5 correspond to FIG. 2, and illustrate a clutch assembly of the apparatus engaged and disengaged, respectively;
- FIGS. 6 and 7 are enlarged views of the clutch assembly of the drilling apparatus and correspond to the circled areas6 and 7 of FIGS. 4 and 5, respectively;
- FIG. 8 shows the lower end of a drill string provided with directional drilling apparatus in accordance with a second embodiment of the present invention;
- FIG. 9 corresponds to FIG. 8, but shows the drilling apparatus in section;
- FIG. 10 is an enlarged sectional view of the drilling apparatus of FIG. 9;
- FIGS. 11 and 12 correspond to FIG. 9, and illustrate a clutch assemblv of the apparatus engaged and disengaged, respectively; and
- FIGS. 13 and 14 are enlarged views of the clutch assembly of the drilling apparatus and corresponding to the circled areas13 and 14 of FIGS. 11 and 12, respectively.
- Reference is first made to FIG. 1 of the drawings, which illustrates the lower end of a
drill string 20 located within adrilled bore 22. Thestring 20 includes astabiliser 24, drilling apparatus in accordance with a first embodiment of the present invention in the form of a rotarysteerable tool assembly 26, and adrill bit 28 joined to thetool assembly 26 by a connectingsub 30. Thetool assembly 26 comprises astabiliser 32 and anonrotating offset mass 34. - Reference is now also made to FIG. 2 of the drawings, which illustrates the
tool assembly 26 in section. The main features and operation of thetool assembly 26 will be described initially, followed by a more detailed description of the individual elements of theassembly 26. - The
offset mass 34 of thetool assembly 26 defines anoffset bore 36 through which atubular mandrel 38 extends. Themass 34 is free to rotate on themandrel 38 and thus tends to remain in the same orientation while thedrill string 20, and thus themandrel 38, is rotated within thebore 22; thetool assembly 26 will only operate in inclined well bores, where theoffset mass 34 will position itself to the lower side of the well bore. - In this particular example, for use in a 33.2 cm (12¼inch) bore, the
mass 34 is formed of steel and is approximately 4.6 m (15 feet) long and has a mass of 1000 kg (2,200 lbs). The mass is arranged such that if s centre of gravity is offset from the mandrel axis by 4.83 cm (1.90 inches), producing a resistive torque of approximately 48 Nm (400 ftlbs). - The
mandrel 38 also extends through thestabiliser 32 and is connected to anannular stabiliser body 40 which defines, in this example, three helical blades 42 (see FIG. 1), each of which accommodates a series of oistons which may be radially extended from theblades 42. The inner end portions of thepistons 44 engage a non-rotating element in the form of acam 46 which is normally coupled, via aclutch assembly 48, to theoffset mass 34. Accordingly, as thedrill string 20 is rotated, theoffset mass 34 andcam 46 remains substantially stationary within the bore, the high spot on thecam 46 forcing thestabiliser pistons 44 outwardly against the bore wall with each revolution of thestring 20. In the illustrated example thepistons 44 will be pushed outwardly into contact with the right hand side of the bore, pushing thedrill bit 28, and thus the trajectory of the bore, to the left. - A more detailed description of the
tool assembly 26 will now be provided, with reference also to FIGS. 3 to 7 of the drawings. - The
stabiliser 24 is connected by way of a threaded connection to atop sub 50 of thetool assembly 26. Thetop sub 50 provides an entry for drilling fluid into the tool assembly and accommodates a fluid actuatedlatch assembly 52 which is used to maintain theclutch assembly 48 in the engaged or disengaged configuration; FIG. 3 illustrates thelatch assembly 52 maintaining the clutch 48 in the disengaged configuration. - The
latch assembly 52 includes alock tube 54 which is axially slidable within thetop sub 50 and defines a venturi 55 towards its upper end. Thelock tube 54 is biassed upwardly by acoil spring 58, aguide ring 60 retaining the lower end of thespring 58 relative to a cartridge case 6l between thetube 54 and the sub bore wall. Fixed centrally within thetop sub 50 and above thecartridge case 61 is an obstructor member orrocket 62, the lower end of which co-operates with theventuri 56 to limit the flow area through thetop sub 50. The interaction of therocket 62 and theventuri 56 allows the configuration of thelatch assembly 52 to be monitored from the surface: in the configuration shown in FIG. 3 the lower end of therocket 62 is spaced from theventuri 56, such that the pressure drop across theventuri 56 is relatively low; however, in the position shown in FIG. 4 of the drawings, therocket 62 extends through theventuri 56, restricting the flow area and creating an additional back pressure which may be detected at surface. When there is little or no fluid flow through thetop sub 50, thespring 58 lifts the lower end of thelock tube 54 free of adouble acting latch 64, thus permitting movement of acollet 66 from one side of thelatch 64 to the other; thecollet 66 is fluted and spring tensioned such that it may be deflected inwardly to travel over thelatch 64. - The
collet 66 is threaded to the upper end of themandrel 38 and slides within acolet support sleeve 68 which extends through the lower end of thetop sub 50. Atubular shroud 69 below thesleeve 68 extends into anouter sleeve 70 connected to thetop sub 50 by threadedconnection 72. Thesleeve 70 is splined to themandrel 38 to prevent relative rotation thereof. To prevent creation of a fluid lock, mud pressure is compensated for at the upper end of the mandrel by acompensation ring 74 which is movable in anannular chamber 71 formed between theshroud 69 and thesleeve 70. The lower portion of thechamber 71 is filled with oil via asleeve port 76. External drilling fluid is permitted to pass through theouter sleeve 70 into the upper portion of thechamber 71 via aport 78 on the opposite side of thecompensation ring 74 from theoil fill port 76. The mud pressure on either side of themandrel 38 and theshroud 69 may thus be balanced to allow easier movement of themandrel 38. - As described above, the
mandrel 38 extends through the offsetmass 34 and thestabiliser 32, the lower end of the mandrel being connected by way of a threadedconnection 80 to therotating stabiliser body 40. Thepistons 44 mounted within thebody blades 42 are mounted onroller bearings 82 which transfer the lateral movement produced by the offset iscam 46 to thepistons 44. Three sets ofbearings 84 perm4it rotation of themandrel 38 andstabiliser body 40 relative to thecam 46. - The upper end of the
cam 46 extends above thestabiliser body 40 and is connected to aflange 86 with atoothed face 87 forming the lower portion of theclutch assembly 48. The upper portion of theclutch assembly 48 is formed by a correspondingflange 88 with atoothed face 89 provided on a lower end of the offsetmass 34. - With the
clutch assembly 48 engaged thecam 46 is rotationally fixed relative to theofset mass 34. However, with theclutch assembly 48 released, thecam 46 is free to rotate relative to themass 34. Further, as illustrated in FIGS. 6 and 7 of the drawings, theclutch assembly 48 is arranged such that, when disengaged, thecam 46 is rotationally fixed relative to themandrel 38. This is achieved by mounting aleaf spring 90 in aslot 92 in themandrel 38 at theclutch assembly 48. Apin 94 is provided on the free end of thespring 90 and with the clutch engaged contact between a raised portion of thespring 96 and the inner wall of theupper flange 88 pushes thepin 94 into arecess 98 formed in themandrel 38. However, when the clutch 48 is disengaged, and themandrel 38 moves downwardly relative to the upperclutch face 89, the raisedportion 96 moves into the gap between thefaces recess 100 provided in theflange 86. This has the effect of connecting theflange 86 and thus thecam 46 to themandrel 38 such that rotation of themandrel 38 results in corresponding rotation of thecam 46. - In use, the
drill string 20 is rotated in thebore 22 with thedrill bit 28 in contact with the cutting face. Drilling fluid is pumped through thestring 20 from the surface, the fluid exiting through nozzles in the bit 28 (shown as 101 in FIG. 2), and then carrying rock fragments from the cutting face up through the annulus between thestring 20 and bore 22. Theclutch assembly 48 is engaged such that the offsetmass 34 and thecam 46 are connected and remain stationary as thestring 20 and the remainder of thetool assembly 26 rotate. As described above, the offsetmass 34 locates itself on the lower side of the inclined bore and such that the high point on thecam 46 remains at the desired orientation within thebore 22, causing thepistons 44 to be extended as they pass over the high point, and tending to deflect thebit 28 towards the opposite side of the bore. - The drilling fluid flowing through the
string 20 creates a pressure differential across theventuri 56 such that thelock tube 54 is pushed downwards against the action of thespring 58. The lower end of thelock tube 54 locks thecollet 66 on the upper side of the double actinglatch 64. Accordingly, as long as the flow of drilling fluid is maintained thecollet 66 will be locked in thelatch 64, theclutch assembly 48 will remain engaged, and the orientation of thecam 46 will be maintained. - To alter the orientation of the
cam 46 and change the bore trajectory, the pumping rate of the drilling fluid is reduced sufficientlv to allow thespring 58 to push thelock tube 54 upwardly, clear of thelatch 64. Tf thestring 20 is then lifted from bottom, thetop sub 50,latch assembly 52,outer sleeve 70 and offsetmass 34 are raised relative to themandrel 38. The weight of themandrel 38, thestabiliser 32 and thedrill bit 28 pull thecollet 66 downwards over thelatch 64. If the drilling fluid flow rate is then increased once more, thelock tube 54 is pushed downwards and locks thecollet 66 on the lower side of thelatch 64 as illustrated, For example, in FIGS. 2 and 5. - As mentioned above, the resulting upward movement of the offset
mass 34 relative to thestabiliser 32 results in the clutch 48 disengaging, and also thecam 46 being coupled to themandrel 38. Accordingly, by slowly rotating thedrill string 20 it is possible to alter the orientation of thecam 46, the orientation of thecam 46 being electronically signal to the operator on the surface by way of conventional LWD (measuring while drilling) apparatus which apparatus is well known to those of skill in the art. - When the
cam 46 is in the desired orientation, the drilling fluid flow rate is reduced once more, such that thelock tube 54 moves upwardly, out of engagement with thecollet 66. If weight is applied to thestring 20, thecollet 66 will then ride over thelatch 64 to re-engage the clutch 48, and disengage thepin 94 from theflange 86 such that thecam 46 is again free to rotate relative to themandrel 38. If the drillirn fluid flow rate is increased once more thelock tube 54 moves down to locks thecollet 66 in thelatch 64, and drilling may then continue. - Reference is now made to FIGS. 8 through 14 of the drawings, which illustrate directional drilling apparatus in accordance with a second embodiment of the preferred invention. The second embodiment shares a number of features with the first described embodiment, and these common features will not be described aaain in detail, and will be accorded the same reference numerals as were used when describing the first embodiment. The principal difference between the embodiments lie in the rotary steerable
cool assembly 126, and more particularly in the eccentric or offsetstabiliser 132. In the second embodiment thestabiliser 132 is provided with an eccentric or offsetstabiliser body 140 which is normally rotatable on themandrel 138. Thus, when the offsetmass 34 and thestabiliser body 140 are connected via theclutch assembly 148, thestabiliser body 140 remains stationary as thestring 20 is rotated. The trajectory of the bore is thus determined by the orientation of thestabiliser body 140. - The orientation of the
stabiliser body 140 is changed in a similar manner to thecam 46 as described above in the first embodiment, that is by configuring thelatch assembly 52 to allow disengagement of the clutch 148 and to couple thestabiliser body 140 to themandrel 138 to allow the orientation of thebody 140 to be altered relative to the offsetmass 34. - It will be evident to those of ski in the art that the above-described embodiments provide relatively simple arrangements which allow the trajectory of an inclined bore to be varied as desired. Further, the adjustable eccentric stabilisers oermit changes in trajectory to be effected while the
drill string 20 is rotated from the surface and rotation of the drill bit is not solely dependent upon a downhole drilling motor. - It will also be clear to those of skill in the art that the above-described embodiments are merely exemplary of the present invention, and that various modifications and improvements may be made thereto, without departing from the scope of the invention.
Claims (23)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9612524 | 1996-06-14 | ||
GBGB9612524.0A GB9612524D0 (en) | 1996-06-14 | 1996-06-14 | Drilling apparatus |
GB9612524.0 | 1996-06-14 | ||
PCT/GB1997/001596 WO1997047848A1 (en) | 1996-06-14 | 1997-06-13 | Drilling apparatus |
Publications (2)
Publication Number | Publication Date |
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US6321857B1 US6321857B1 (en) | 2001-11-27 |
US20010047884A1 true US20010047884A1 (en) | 2001-12-06 |
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ID=10795339
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/202,342 Expired - Lifetime US6321857B1 (en) | 1996-06-14 | 1997-06-13 | Directional drilling apparatus and method utilizing eccentric stabilizer |
Country Status (9)
Country | Link |
---|---|
US (1) | US6321857B1 (en) |
EP (1) | EP0904478B1 (en) |
AU (1) | AU3099797A (en) |
CA (1) | CA2257951C (en) |
DK (1) | DK0904478T3 (en) |
ES (1) | ES2149600T3 (en) |
GB (1) | GB9612524D0 (en) |
NO (1) | NO314003B1 (en) |
WO (1) | WO1997047848A1 (en) |
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WO2009088571A2 (en) * | 2007-11-19 | 2009-07-16 | Webb Charles T | Counterbalance enabled power generator for horizontal directional drilling systems |
US20100089647A1 (en) * | 2008-10-09 | 2010-04-15 | National Oilwell Varco, L.P. | Drilling Method |
GB2536331A (en) * | 2015-01-12 | 2016-09-14 | Schlumberger Holdings | Active stabilization |
US9689209B2 (en) | 2010-12-29 | 2017-06-27 | Nov Downhole Eurasia Limited | Large gauge concentric underreamer |
US9909367B2 (en) | 2012-08-29 | 2018-03-06 | Nov Downhole Eurasia Limited | Downhole tool with rotational drive coupling and associated methods |
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US7178611B2 (en) * | 2004-03-25 | 2007-02-20 | Cdx Gas, Llc | System and method for directional drilling utilizing clutch assembly |
GB0521693D0 (en) * | 2005-10-25 | 2005-11-30 | Reedhycalog Uk Ltd | Representation of whirl in fixed cutter drill bits |
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US8727036B2 (en) | 2007-08-15 | 2014-05-20 | Schlumberger Technology Corporation | System and method for drilling |
CN103774990A (en) * | 2007-08-15 | 2014-05-07 | 普拉德研究及开发股份有限公司 | Method and system for controlling well drilling system for drilling well in earth stratum |
US8720604B2 (en) | 2007-08-15 | 2014-05-13 | Schlumberger Technology Corporation | Method and system for steering a directional drilling system |
US20100038141A1 (en) | 2007-08-15 | 2010-02-18 | Schlumberger Technology Corporation | Compliantly coupled gauge pad system with movable gauge pads |
US8534380B2 (en) | 2007-08-15 | 2013-09-17 | Schlumberger Technology Corporation | System and method for directional drilling a borehole with a rotary drilling system |
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CN103696706A (en) * | 2012-09-28 | 2014-04-02 | 中国石油化工股份有限公司 | Remote-control-while-drilling tapered stabilizer |
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WO2015117151A2 (en) | 2014-02-03 | 2015-08-06 | Aps Technology, Inc. | System, apparatus and method for guiding a drill bit based on forces applied to a drill bit |
WO2015122916A1 (en) | 2014-02-14 | 2015-08-20 | Halliburton Energy Services Inc. | Uniformly variably configurable drag members in an anti-rotation device |
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WO2015122917A1 (en) | 2014-02-14 | 2015-08-20 | Halliburton Energy Services Inc. | Individually variably configurable drag members in an anti-rotation device |
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CA2964748C (en) | 2014-11-19 | 2019-02-19 | Halliburton Energy Services, Inc. | Drilling direction correction of a steerable subterranean drill in view of a detected formation tendency |
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IT201700117866A1 (en) * | 2017-10-18 | 2019-04-18 | Eni Spa | DRILLING EQUIPMENT AND METHOD FOR UNLOCKING DRILL AUCTIONS INTO A SURROUNDING LAND |
IT201800009857A1 (en) * | 2018-10-29 | 2020-04-29 | Eni Spa | SYSTEM FOR UNLOCKING THE RODS OF A BATTERY OF RODS OF A DRILLING APPARATUS. |
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-
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- 1996-06-14 GB GBGB9612524.0A patent/GB9612524D0/en active Pending
-
1997
- 1997-06-13 ES ES97926112T patent/ES2149600T3/en not_active Expired - Lifetime
- 1997-06-13 WO PCT/GB1997/001596 patent/WO1997047848A1/en active IP Right Grant
- 1997-06-13 US US09/202,342 patent/US6321857B1/en not_active Expired - Lifetime
- 1997-06-13 DK DK97926112T patent/DK0904478T3/en active
- 1997-06-13 CA CA002257951A patent/CA2257951C/en not_active Expired - Lifetime
- 1997-06-13 AU AU30997/97A patent/AU3099797A/en not_active Abandoned
- 1997-06-13 EP EP97926112A patent/EP0904478B1/en not_active Expired - Lifetime
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1998
- 1998-12-11 NO NO19985812A patent/NO314003B1/en not_active IP Right Cessation
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009088571A2 (en) * | 2007-11-19 | 2009-07-16 | Webb Charles T | Counterbalance enabled power generator for horizontal directional drilling systems |
WO2009088571A3 (en) * | 2007-11-19 | 2009-10-01 | Webb Charles T | Counterbalance enabled power generator for horizontal directional drilling systems |
US20100089647A1 (en) * | 2008-10-09 | 2010-04-15 | National Oilwell Varco, L.P. | Drilling Method |
US8550183B2 (en) * | 2008-10-09 | 2013-10-08 | National Oilwell Varco, L.P. | Drilling method |
US9689209B2 (en) | 2010-12-29 | 2017-06-27 | Nov Downhole Eurasia Limited | Large gauge concentric underreamer |
US9909367B2 (en) | 2012-08-29 | 2018-03-06 | Nov Downhole Eurasia Limited | Downhole tool with rotational drive coupling and associated methods |
GB2536331A (en) * | 2015-01-12 | 2016-09-14 | Schlumberger Holdings | Active stabilization |
US10669788B2 (en) | 2015-01-12 | 2020-06-02 | Schlumberger Technology Corporation | Active stabilization |
Also Published As
Publication number | Publication date |
---|---|
NO985812L (en) | 1999-02-12 |
CA2257951A1 (en) | 1997-12-18 |
DK0904478T3 (en) | 2000-12-18 |
AU3099797A (en) | 1998-01-07 |
NO314003B1 (en) | 2003-01-13 |
CA2257951C (en) | 2006-08-15 |
US6321857B1 (en) | 2001-11-27 |
GB9612524D0 (en) | 1996-08-14 |
WO1997047848A1 (en) | 1997-12-18 |
ES2149600T3 (en) | 2000-11-01 |
NO985812D0 (en) | 1998-12-11 |
EP0904478B1 (en) | 2000-08-23 |
EP0904478A1 (en) | 1999-03-31 |
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