CA1139298A - Hydraulically powered drilling sub for deepwell drilling - Google Patents
Hydraulically powered drilling sub for deepwell drillingInfo
- Publication number
- CA1139298A CA1139298A CA000359212A CA359212A CA1139298A CA 1139298 A CA1139298 A CA 1139298A CA 000359212 A CA000359212 A CA 000359212A CA 359212 A CA359212 A CA 359212A CA 1139298 A CA1139298 A CA 1139298A
- Authority
- CA
- Canada
- Prior art keywords
- rotor
- motor
- drilling
- housing
- sub
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005553 drilling Methods 0.000 title claims abstract description 52
- 239000012530 fluid Substances 0.000 claims abstract description 15
- 239000003381 stabilizer Substances 0.000 claims abstract description 11
- 238000006073 displacement reaction Methods 0.000 claims abstract description 10
- 230000008878 coupling Effects 0.000 claims description 13
- 238000010168 coupling process Methods 0.000 claims description 13
- 238000005859 coupling reaction Methods 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 4
- 239000011796 hollow space material Substances 0.000 claims 1
- 239000007788 liquid Substances 0.000 description 7
- 229920000136 polysorbate Polymers 0.000 description 5
- 241000901720 Stator Species 0.000 description 3
- 238000000576 coating method Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 101100134298 Bacillus subtilis (strain 168) nucA gene Proteins 0.000 description 1
- 241001324870 Lactobacillus iners Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
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
- E21B4/00—Drives for drilling, used in the borehole
- E21B4/02—Fluid rotary type drives
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
- F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
- F01C21/10—Outer members for co-operation with rotary pistons; Casings
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Hydraulic Motors (AREA)
Abstract
ABSTRACT
HYDRAULICALLY POWERED DRILLING SUB
FOR DEEPWELL DRILLING
The hydraulically powered sub for deepwell drilling comprises a hydraulic rotary motor of the positive displacement type (such as a vane motor and a Moineau motor).
The outer surface of the housing of the motor is provided with sections having the outer surface thereof at various radii with respect to the central axis of the housing. The large-radius sections form stabiliser wings and house at least part of the hydraulic motor, such as hydraulic conduits, vanes, slots for vanes, or fluid compartments.
HYDRAULICALLY POWERED DRILLING SUB
FOR DEEPWELL DRILLING
The hydraulically powered sub for deepwell drilling comprises a hydraulic rotary motor of the positive displacement type (such as a vane motor and a Moineau motor).
The outer surface of the housing of the motor is provided with sections having the outer surface thereof at various radii with respect to the central axis of the housing. The large-radius sections form stabiliser wings and house at least part of the hydraulic motor, such as hydraulic conduits, vanes, slots for vanes, or fluid compartments.
Description
~3~
HYDRAULICALLY POWERh~ DRILLING SUB
FOR DEEPI~ELL DRILLING
The invention relates to a hydraulically powered drilling sub for deepwell drilling, in particular for drilling boreholes in sub-surface forMations f'or f'orming wells -throueh which f'lu:ids such as oil, gas or (hot) wa-ter may 'be recovcre--l f'rom said f'orMations. The dri].ling sub is also usef'ul in carryirlg out exploration work in such forrnations.
Hydraulically powered drilling subs including mud-driven hydraulic motors have been described already in nuMerous earlier publications. Such rnotors are either turbine motors or positive displacement motors (such as vane-type motors and motors of the Moineau-type).
The subs have coupling means for coupling the sub to drilling means. Such drilling means include a drill string, a drill collar string and a rotary bit, and the sub is preferably placed between -the rotary bit and the lowermost drill collar of the drill collar string, or between a pair of drill collars.
The invention relates in particular to a hydraulically powered drilling sub including a hydraulic rotary motor of the positive displacement type. The positive displacement motor includes a stator housing with a cen-tral axis, the housing being provided with coupling means adapted to connect the housing directly or indirectly to one part of the drilling means such that the central axis of' the housing coincides with the axis of rotation of the drilling rneans. Thc motor further includes a rotor rotatably arranged within the stator housing, coupling means adap-ted to connect the rot;or direc-tly or in-directly to the other part of the drilling means, i'luid compar-trnents between the inner wall of the s-tato:r housing and the oute.r wall of the rotor, and conduits f'or passine f'lui.ds into and out of'-the com-partments.
The power P developed by u hydraulic motor of'-the~ pos:i-tive displacement type is directly related -to the flow ra-te F of' the fluid -through -the motor and -the difference in pressure ap existing be-tween the f'luid present in the inle-t condui.-t and th~
outlet condu.it through which the f'luid is passed into and out ol' 1^~3~
the fluid compartments, respectively.
Hence, P ~ F ap ( 1 ) ~urther, the mathernatical product of the nurnber o~ revo].utions R of the motor and that par-t V of the volume ol the fl.uid compartments that is displaced prr si.ngle revolutiorJ of -the rnotor is direc-tly proportional to thc flow rate ~i'.
Hcnce, F ~ V ~ (2) I'he displaced volurne V oi the compartrnents per revolution of the motor is referred to hereinafter and in the claims as the "volumè" V of the cornpartments. Further, the expression "volume per unit length"v is introduced, that is the displaced volume of the compartments per unit length thereof (measured in a direction parallel to the central axis of the housing).
Hence, V = v L (3) wherein L is the length of the fluid compartments.
By introducing formuLas 2 and 3 into formuLa 1, it follows that P ~ v L R ~p (~) and T ~ P ~ v I, ~p (5) wherein T is the torque devel.oped by the rnotor.
It will be appreciated that since the mo-tors have to operate in boreholes of relati.vely small cross-sections, -the known motors have the disadvantage that the vo:LI~ne per uni-t length thereof (which is indicated by -the symbol "v" in the above fo:rmulas) is re.:Lati.vely small.
The object of the invention is a hyclra~ ically poweled sub comprising a posi.-ti-ve displacelnent motor Uittl cornpartrrlen-ts ha-ving an increased vol.ume per uni.t length w`nencornp(lred w:i.th thc compartmcn-ts oi the known motors.
As can easily be seen irom Iorrnula 5, an increase of v ;.n mo-tors of a given leng-th L wi:Ll result in an increase of T. If power P is kept constant, an increase of v w;ll result in a reduc-tion o:f R, whi.ch allows the use of a reduction gearbox of smaller dimensions, or even the deletion of the gearbox.
____~ _ __ .
As can further easily be seen from formula 3, application of the invention allows the motor to be built at a reduced length L ~hen compared to kno~m motors. Simpler construction and manufacturing techniques may then be applied which will reduce manufacturing costs.
The hydraulically powered drilling sub for deepwell drilling according to the invention includes a hydraulic rotary motor of the positive displacement type as described above, wherein the outer wall of the stator housing forms at least part of the outer wall of the sub and is provided with sections having the outer surface thereof situated at various radii with respect to the central axis of the housing, the ratio between the minimum and the maximurn radii being at most 0.95, the large-radius sections forrning stabilizer wings, and at least part of these latter sections housing at least parts of the hydraulic rotary motor.
The hydraulic motor may be a vane-type motor having the vanes thereof slidably arranged in slots carried by the rotor. The large-radius sections then house at least part of the fluid conduits.
In another embodiment of the invention, the hydraulic motor is a vane-type motor having at least part of the fluid conduits arranged inside the rotor. The large-radius sections then house slots wherein vanes are slidably arranged.
In still another embodiment of the invention, the hydraulic motor is a Moineau-type motor. The large-radius sections are then helically shaped and enclose part of the compartments between the rotor and sta-tor housing.
In again another embodiment of the invention, the hydraulic motor comprises a rotor having a toothed outer surface co-operating with a plurality of cylindrical bodies that are positioned at regular distances from one another along the inner wall of the stator housing. Each such body is then positioned in a large-radius sec-tion of the stator housine.
It will be appreciated that for a given hole diarneter the use of a stator housing having large-radius sections, locally illcreases -the radius of thehousing wnen compared to circle cylindrical stator housings of prior art hydraulically powered drilling subs. The sections having relatively large radii act as stabilizer wings which can house parts of the hydraulic motor, whereby the compartments of the motor obtain ~3~
an increased volume per unit lengthT,~ncorllpared to prior art motors.
The stabilizer wings stabilize the sub against horizontal deflection in the hole that is being dr lled. If straight sections are used, at least three large-diameter sections should be provided in order that these sections will act as stabilizer wings. Generally four or more cr these sections will be applied, such as from four to eight sections.
If helically shaped sections are used, such as in connect;on with Moineau-Motors, the nurnber of sections is equal to the nurnber of lobes of the stator. Such stator has at least two lobes.
The invention will be described by way of example in more detail with reference to the drawings.
Figure 1 shows schematically a cross-section over a hydraulically powered drilling sub according to the invention, incorporating a sliding vane-type hydraulic motor wherein the sliding vanes are carried by the rotor thereof.
Figure 2 shows a longitudinal section of the drilling sub of Figure 1, taken over section II-II thereof.
Figure 3 shows schematically a longitudinal section over a drilling sub according to the invention of alternative design, wherein the sliding vanes are located in slots situated in the housing of the motor.
Figures 4-8 show cross-sections of the drilling sub of Figure 3, taken over sections IV-IV, V-V, VI-VI, VII-VII, and VIII-VIII respectively.
Figure 9 shows schematically a cross-section over a hydraulically powered drilling sub according to the invention, incorporating a hycraulic motor of the Moineau-type.
Figure 10 is a side view of the sub of Figure 9.
/ Figure 11 shows schematically a cross-section over a drilling sub according to -the invention, incorporating a hydraulic motor of the internal gear type.
The hydYaulica]ly powered drilling sub of Figures 1 and 2 has the vanes 1 -thereof slidably arrarlged in -the slots 2 of the ro-tor 3.
The vanes are pushed against the inner wall of the housing 4 by springs (not shown) arranged be-tween the vanes and -the bottom parts of the slots. The inner wall of the housing 4 is constituted by a wear-resistant lining 6 provided wi-th openings 7, o, 9 and 10. Fluid supply conduits 11, 12 in the housing 4 comrnunicate with the openings 8 and 10, respecti.vely, and fluid discharge condui.ts 13, 14 in the housing )~ comrnunicate with openings 9 and 7, respectively.
Th~ space betwcen the outer wall of' the rotor 3 and the inner non-cylindrical wall of the lining 6 of` housing 4 consists of~ two S parts with crescent-shaped cross-s~ction, which parts are divided into a plurality of' compartmen-ts 15 by -the vanes 1. I-t will be appreciated that the total vol~ne c,f -t'rle compartmerlts .is constant, but that thc vo~.urnc of' each compartrnen-t vrlri.-c be-tween aL,proxirnrll;e:ly ~ero to a rna~;.murn va:Lu( wherl the rotor 3 is ro-tated in the hous;ng L~
around its central axis. l~'lui.d supplied -through supply condu:its 11 and 12 wil] enter the cornpar-tments 15 tha;t are in comrnunication with the ports 8 and 10, respectively, and acti-vate the rotor 3 to rotate around its central axis. The coMpartments 15 tha-t are in comounieation with the f'luid discharge conduits 13 and 14 wil] exhaust in these conduits through the ports 9 and 7, respectively.
The supply conduits 11 and 12 via which liquid is supplied to the ports 8 and 10, respectively, communicate with passages 17 (one of which is shown in ~igure 2) in the tubular member 18 that is connected to the upper encL of the housing 4 by means of a screw thread 19. The tubular rnember 18 is provided with an int~rnal screw thread 20 for connecting the hydraulically powered drilling sub to drilling means (not shown) such as the lower end of a drill collar.
A bearing 21 is carried by the tubular member 18, and the shaft 22 of the rotor 3 is rotatably supported by said bearing 21. A cheek plate 23 w:ith wear-resistant lining 2ll is arranged be-tween -the tubular member 18 and -the rotor 3. The upper erld of the s:lots 2 housing -the vanes 1, as well as the upper end of' thc space consisting o:f compartments 15 are sealed off' by said cheek pla-te 23.
A second cheek plate 25 wi-th wear-res:i.strlrl-t l:inillg 26 is arrangc?d at the lower end of' the rotor 3 f'or closing of':f' L,he :L.owcr c~nds oL` the slots 2 and the space consist:illg of'(ompar-tmcrlts 15. I'hiS .1.owcr Clld of the rotor 3 ir; provided. wi-th a shaI't 27 that is suppc)r-ted by bear-ings 28 and 29 that are house~d in tubular mernber 31.
Two passages 32 (only one of' which is shown in broken lines) are arranged part:l.y in -the lower end of'-the housing ll anL par-tly ~3~
in the tubular member 31 ? each of s.aid passages, communicating at one end thereof with one of the discharge conduits 13 and 14, and with the other ends thereof wi-th the space 33 above the sealing member 34 in the tubular mernber 35 that is coupled to the housing 4 by means of' a screw thread 36. Tubular member 31 is being prevented from rotation with respect to the housing 4 by means of a key 37.
A splined shaft 38 cooperating with a splined opening 39 in the lower end of the rotor 3, is attached to the mernber 40 that is connected by a screw thread 41 to the dri].l shaft 42 having a central bore 43. Space 33 communicates with the central bore 43 via openings 44 in member 40. Any liquid that is leaving the compartments 15 can thus flow via drain conduits 13 and 14, channels 32, space 33, openings 44 and central bore 43 to a rotary drilling bit (not shown) that is coupled to the lower end of the drill shaft 42. Axial loads 'between the shaft 42 and the housing 4 are taken up by the thrust bearing 45 comprising a plurality of spacer rings 46 mounted on the drill shaft 43 by means of a screw ring 477 and a plurality of spacer rings 48 cooperating with the rings 46 and mounted inside the tubular member 35 by means of a screw ring 49. Cooperating surfaces of the rings 46 and 48 may be provided with wear-resistant linings (not shown) and suitable channels or passages (also not shown) may be arranged for supplying liquid to the thrust bearing 45 for cooling and lubricating purposes. This type of thrust bearing is known per se and does not require a detailed description.
As can best be seen in Figure 1 of the drawings, the cross-section of the housing 4 is such that passages 50 are present between the outer wall of the housine 4 and the inner wall of the borehole (see broken line 51). The housing 4 there'by acts as a stabilizer when the sub is being operated in the hole 51. The passages 50 are used for the return flow of the mud through the bore-hol~ 51-The four large-radius sections 52 of the housi.ng 4 form wings that stabilize the hydraulic sub and the drilli.ng bit driven thereby in the borehole, whereby horizontal deflection of the borehole is prevented, or at least minimized.
1139~
The ratio between the smallest radius of each of the sections 53 located between two of the large-radius sections 52 is at most 0.95.
By arranging the conduits 11-1~ in the large-diameter sections 53 of the housing 4 that forms the stabilizer wings, the radius of the lining 6 can be increased as compared to prior art hydraulically powered drilling subs that incorporate vane-motors with housings having cylindrical outer walls. This allows an increase of the volume of the compartments per unit length of the rotor, whereby the advantages as explained hereinbefore will be gained, In an alternative embodiment of the invention, as shown in Figures 3-8 of the drawings, the large-radius sections of the housing of the vane-motor form stabilizer wings and house the slots of the vanes. The same advantages as referred hereinabove are then obtained.
The hydraulically powered drilling sub of Figures 3-8 comprises a housing 60 (see in particular Figure 3 and Figure 6, which latter figure shows a cross-section over the motor of Figure 3 taken at the level of the middle of the rotor thereof) comprising eight large-radius sections 61. These sections are of slightly smaller radius, than the borehole 62, and each space 63 enclosed by a pair of sections 61 nearest thereto and by the borehole wall acts as a return passage for the mud in the hole 62.
Each large-radius section 61 houses a slot 6~ in which a vane 65 is slidably arranged. Springs (not shown) are arranged between the bottom of each slot and the vane,in said slot. A rotor 66 is arranged in the bore of~the housing 60, and the space between the rotor 66 and the housing 60 is divided into a plurality of compartments 67 by the vanes 65. The central axes of the rotor 66 and of the housing 60 coincide and the outer wall of the rotor 66 is shaped such that the volumes of the various compartments 67 vary when the rotor 66 is rotated. Rotation of the rotor is 'brought 113~
forward by the supply of pres.sure liquid via the charmels 68 and 69 in the rotor 66. This liquid passes through ports 70 and 71, respectively, that are arranged in the wall of the rotor 66. After passing through the cornpartments 67 in the space between the rotor 66 and the housing 60, the liquid is discharged via the ports 72 and 73, respectively, and leaves the vane motor through discharge channels 74 and 75 that are arranged within the rotor 66.
The supply channels 68, 69 and the discharEe channels 74, 75 are formed by the insert piece 76 that is situated in the central bore of the rotor 66. This insert piece 76 consists of four walls that form the supply channels 68, 69 such that the cross-section of each channel decreases in downward direction (see Figures 4-8), whereas the discharge charmels 74, 75 each have a cross-section that increases in downward direction (see Figures 4-8). Since each channel cornmunicates with a row of ports 70-73, and each row extends in longitudinal direction along a channel, the flow of liquid through each channel will be approximately equal along the length of each channel. The fluid pressure at each inlet port of the rows of inlet ports 70, 71 will therefore be substantially equal. Also, the fluid pressure at each outlet port of the rows of ou-tlet ports 72, 73 will therefore be substantially equal. As a result thereof, each blade 65 will be subjected to a uniform driving pressure over its length.
The insert piece 76 is sealingly connecied to the wall of the central bore of the rotor 66, and secured against axial as well as rotational displacements within said bore.
The slots 64 and the compartments 67 are sealed o~'f at the upper and lower ends thereof by cover elements 77, 78, respectively (see Figure 3). These elements are connected to the housi.ng 60 by a plurality of ].ocking bolts 79 passing through holes in recessed parts 80 (see broken lines) of the elements 77, 78 and screwed in screw-threaded holes arranged in the stator housing 60. A coupling element 81 provided with an internal screw thread 82 for connecting the hydraulically powered drilling sub to a drill collar is connected to the cover element 77 by rrleans of a screw thread 83.
Flement 81 is provided with a bearing 84 for supporting the upper shaft 85 of the rotor 60.
The lower shaft 86 of the rotor 60 is supported by a bearing 87 carried by the sleeve member 88 that is connected to -the cover element 78 by means of a screw thread 89. The sleeve member 88 houses a thrust bearing 90 for transmitting axial loads between the drill sha~t 91 and the housing 60. The drill shaft 91 is coupled to the lowcr end of the rotor shaf't 86 by rneans O:r a screw thread 92, and -the space between the drill shaf't 91 and -the bushine 88 is filled with lubricarlt and closed of`i' by 5eal'~ 93, 94 that are kept in place in an appropriate manner such as by snap-rines (not shown ) .
The lower end of'-the shaft 91 is provided with Q screw thread 95 f'or coupling a (not sho~m) drill bit to this shaft.
The embodimen-t of the invention shown in Figures 3-8 has the slots 64 of the vanes 65 arranged in the large-radius sections 61 f the housing 60, which sections act as stabilir/er wings. By this arrangement of the vanes, the compartments 67 have a large volume per unit length. The advantages thereof have already been explained herein-before.
Although the embodiments shown by way of example in the drawings both show a hydraulically powered drilling sub wherein the vane motor comprises rigid vanes that are slidably arranged in slots, the invention is not limited to this type of vanes. Equal good results will be obtained when applying the invention in a hydraulically powered drilling sub having a vane motor with flexible vanes. These vanes may be f'ormed by flexible sheets that are connected to the rotor (or to the housing) along onel~or~itudinal edge -thereof'. Also, such vanes may consist of rigid e]ongate elements that are hingedly connected (such as by means of' a flexible sheet) to the housing or rotor o~ the vane motor. Exarnples of flexible vanes are shown in U.S. patent specificatior1s Nos. 2,655,3ll4 and 3,301l,838; and German patent specificci-tion 1,025,359. In again another ernbodi,ment of the invention, the va,nes may be formed by cylindrical bodies that have the central axes thereof' parallel -to the cel1tral axis oI' the rotor. An exarnple of this type of motor is described in Bri,-tish patent specification 1,443,6~4.
The two embodiments shown in Eigures 1-8 oL' the draw;ngs in-corporate balanced vane motors having two sets of inle-t ports and ]o t~"o sets of outlet ports. MlLLti-balanced vane motors may be applied as well, such as mo-tors having three sets of inlet ports and three sets of outlet ports. It is observed tha-t unbalanced motors having a sing]e set, of inl.et por-ts and a single se-t of outlet ports are o:ften ]iable to jarnrning of the rotor in -the housing and -therefore not pr-f'erred.
'Lhe vanes ina~ be prec;scd f~or s~aling purposc-s against the inner wall of thc housine (whc?n the vanes are rnounted in the rotor) or againSt the outer wa].:L of the rotor (~"hen the vanes are mounted in the housing) by springs mounted between the vanes and the bo-ttom of the slots as well as -by any other Means suitable f'or the purpose.
Such means are known per se and do not need a detailed description.
Wear-resis-tant l.iners and/or coatings may be applied at -those surfaces where excessively large wearing forces will be generated.
Suitable materials for such liners and coatings as well as treating methods for increasing the resistance against wear of materials are known and these may ~be applied in the drilling sub of the present invention where such is deemed necessary. In particuLar, such wear-resistant linings may be used for covering the stabilizer wings over ~ those areas where the wings contact the borehole wall during drilling operations.
The present in-vention may further be applied to hydraulically powered drilling subs comprising one or more positive displacement motors of the Moincau-type, wherein each motor comprises a helically-shaped ro-tor that ;.s ro-tata.b]y a.rranged within a helica.lly-shapc?d stator. A plurality of' f'luid compa.rtmc?rl-ts ;s I'orinccl belween the rotor and the stator, w}l;.ch comparl;ments are disll.-~ced he]ically arouncl the central axis of the Mo:ineall-lnotor wherl th( rol;or is displaced in -the stator. DurinFr such displacernent, tllc rotor rotates around i-ts axis and simu:l.taneously orb:its aroun(l thc central .IXiS
of' the sta-tor, arld thc~-torque exer-ted on the rolor by ~the driling fluid is transferrecl ViQ a f:lexib:Lc or universal coupling to a shaft tha-t is support.ed axi.ally within the ~.ower end of thc stator housing and adapted to be connected to a drill bit.
35 F'igure 9 of the drawings shows a cross-sec-tion over a dri:Lling 1~3~2~1~
sub with a hydraulic motor of the Moineau-type, wherein a three-lobed rotor iO0 cooperates with a four-lobed stator 101.
In the embodiment shown, the rotor 100 is made of metal, such as steel, whereas the stator 101 is of flexible material, such as rubber or an elastomer rnaterial. The stator 101 is supported in a stator housing 102 having helical large-radius sections 103 as can best be seen in Figure 10 which shows a side view of the motor of Figure 9. Figure 9 shows a cross-section of the motor taken over section IX-IX of Figure 10. The sections 103 of the stator housing 102 have helical grooves 104 therebetween which allow return mud to pass alongside the housing 102 when the motor is operating in a hole 105 (seebroken line in Figure 9). The space within the large-radius sections 103 is used for housing the lobes of the stator 102 and it will be appreciated that the volume per unit length of the compartments of the Moineau-rnotor is considerably increased in this manner when comparing it with prior art Moineau-motors designed for the same drilling diameter.
The stator housing 102 is provided with a screw-threaded coupling 106 by which the Moineau-motor can be coupled to the drill string, whereas the screw-threaded coupling 107 on the rotatable shaft 108 can be connected to a rotary bit. As mentioned already hereinabo~e, the shaft 108 is coupled to the rotor 100 by means of a flexible coupling (not shown). Since all these details of the Moineau-motor are known per se, they are not discussed here in detail.
Finally, Figure 11 of the drawings shows a cross-section over a drilling sub with a hydraulic motor of the internal gear type.
This motor includes a stator housing 110 and an outer gear set consisting of rollers 111 arranged parallel to the central axis 112 of the stator housing at regl~ar distances froTn each other.
3 A part of each roller is enclosed by a cylindrical bearing formed in a recess in the wall of the stator housing 110. The rollers are rotatably arranged in the bearings and cooperate with an inner gear set formed by the toothed rotor element 1l3 that is adapted to rotate around the central axis 114 thereof and to orbit simultaneously around the central axis 112 of the stator housing 110.
~L~3~
Fluid cor.qpartments 115 are present between the rotor element 113, the stator housing 110 and the rollers 111, and pressure fluid can be supplied to -these co-mpartmer-ts ~ria the openings 116 tha-t are arranged at one end of the cornpar-tmerlts. The passage through -these openings is controllcd 'by a val~re platc- (no-t shown) that is rotatecL in conjunction wi-th the rotor 113. Sir(lilar valve con-trolled opc-nings (not sho~/n) arc f'urther provi.d(d at the other end of the comI~artments 115. 'l'ne ~alve pl.ltes cor~tro:L-thc en-try oI' high pressure f'lui.d into the compartrncntC arld -the cxhaust therco~' I'rom the compartments as a result whereof'-the rotor 11. carries out a rotational and or'bit~l movernent. The ro-tor is coupled to the drilling shaf't by (not sho~n) gear means or a (not shown) shaf't via universal coupling means, and on Movement of -the rotor, the teeth thereof co-operate with the rollers 111. A more detailed description of -this type of hydraulic positive displacement motor can be found in U.S. patent specif'ication 3,289,602 (patented 6th December, 1966, Inv. Bernard C. Hudgens, assignor to T~W Inc.~.
In accordance with the invention, the outer wall of the stator housing 110 of the motor shown in Figure 11 comprises large-radius sections 11 r that house the rollers 111 o~ the motor. Be-tween the eight large-radius sections 117 there are eight small-radius sections 110 along which return mud can flow between the outer wall of the sub and -the wall 119 o~ the borehole.
It will be appreciated that the shape of the non-c:ylindrical outer walls of the sta-tor housings that form at least par-t of the outer walls o~ the hydrau~Lically actuated drilling subs according to the i.nvention should be chosen such -that a pasca~eway of suffi.cien-t cross-section fo:r a:Llowing the f':Lowci' rc-tu1rlrrlud is lef-t 'betwren -the oll-ter wal] of -the stal;or hC)Us; n~ ar1d thc wall Or the borehole in which thc motor .is o-perc~tirlg. 'L'o th:i cn(L, the ratio between the m;.n;.rmlrn radius and -the muximl1M ru(l:ill; c~t' the outc:Lwall of the s-ta-tor housing ;hould be not l.arger tharl().95. 'L'l-~e large-radius sect;r)rls of'-the housing, Wh;.C~I f'orm the stai)il:i%c:r wi.ngs, may have a rLi.arneter that is s:Lightly less tharl the hole d;.ameter (say, betweerl 9~.0 an(l 99.6% -thercoI') wrlereus the small-~3~
radius sections situated between the wings form the passage ways for the return mud. It will be understood that the ratio between the rninimurn radius and the maximum radius of the outer wall of the stator housing is further selected in dependence on the number of wings and the si~e thereof in tangential direction with respect to the stator housing. Wnlen increasing the nwnber of` wings and/or increasing the width of the wings, lower ratios should be applied, such as between 0.ô5 and 0.75 in order to create a return mud passage of sufficient area.
HYDRAULICALLY POWERh~ DRILLING SUB
FOR DEEPI~ELL DRILLING
The invention relates to a hydraulically powered drilling sub for deepwell drilling, in particular for drilling boreholes in sub-surface forMations f'or f'orming wells -throueh which f'lu:ids such as oil, gas or (hot) wa-ter may 'be recovcre--l f'rom said f'orMations. The dri].ling sub is also usef'ul in carryirlg out exploration work in such forrnations.
Hydraulically powered drilling subs including mud-driven hydraulic motors have been described already in nuMerous earlier publications. Such rnotors are either turbine motors or positive displacement motors (such as vane-type motors and motors of the Moineau-type).
The subs have coupling means for coupling the sub to drilling means. Such drilling means include a drill string, a drill collar string and a rotary bit, and the sub is preferably placed between -the rotary bit and the lowermost drill collar of the drill collar string, or between a pair of drill collars.
The invention relates in particular to a hydraulically powered drilling sub including a hydraulic rotary motor of the positive displacement type. The positive displacement motor includes a stator housing with a cen-tral axis, the housing being provided with coupling means adapted to connect the housing directly or indirectly to one part of the drilling means such that the central axis of' the housing coincides with the axis of rotation of the drilling rneans. Thc motor further includes a rotor rotatably arranged within the stator housing, coupling means adap-ted to connect the rot;or direc-tly or in-directly to the other part of the drilling means, i'luid compar-trnents between the inner wall of the s-tato:r housing and the oute.r wall of the rotor, and conduits f'or passine f'lui.ds into and out of'-the com-partments.
The power P developed by u hydraulic motor of'-the~ pos:i-tive displacement type is directly related -to the flow ra-te F of' the fluid -through -the motor and -the difference in pressure ap existing be-tween the f'luid present in the inle-t condui.-t and th~
outlet condu.it through which the f'luid is passed into and out ol' 1^~3~
the fluid compartments, respectively.
Hence, P ~ F ap ( 1 ) ~urther, the mathernatical product of the nurnber o~ revo].utions R of the motor and that par-t V of the volume ol the fl.uid compartments that is displaced prr si.ngle revolutiorJ of -the rnotor is direc-tly proportional to thc flow rate ~i'.
Hcnce, F ~ V ~ (2) I'he displaced volurne V oi the compartrnents per revolution of the motor is referred to hereinafter and in the claims as the "volumè" V of the cornpartments. Further, the expression "volume per unit length"v is introduced, that is the displaced volume of the compartments per unit length thereof (measured in a direction parallel to the central axis of the housing).
Hence, V = v L (3) wherein L is the length of the fluid compartments.
By introducing formuLas 2 and 3 into formuLa 1, it follows that P ~ v L R ~p (~) and T ~ P ~ v I, ~p (5) wherein T is the torque devel.oped by the rnotor.
It will be appreciated that since the mo-tors have to operate in boreholes of relati.vely small cross-sections, -the known motors have the disadvantage that the vo:LI~ne per uni-t length thereof (which is indicated by -the symbol "v" in the above fo:rmulas) is re.:Lati.vely small.
The object of the invention is a hyclra~ ically poweled sub comprising a posi.-ti-ve displacelnent motor Uittl cornpartrrlen-ts ha-ving an increased vol.ume per uni.t length w`nencornp(lred w:i.th thc compartmcn-ts oi the known motors.
As can easily be seen irom Iorrnula 5, an increase of v ;.n mo-tors of a given leng-th L wi:Ll result in an increase of T. If power P is kept constant, an increase of v w;ll result in a reduc-tion o:f R, whi.ch allows the use of a reduction gearbox of smaller dimensions, or even the deletion of the gearbox.
____~ _ __ .
As can further easily be seen from formula 3, application of the invention allows the motor to be built at a reduced length L ~hen compared to kno~m motors. Simpler construction and manufacturing techniques may then be applied which will reduce manufacturing costs.
The hydraulically powered drilling sub for deepwell drilling according to the invention includes a hydraulic rotary motor of the positive displacement type as described above, wherein the outer wall of the stator housing forms at least part of the outer wall of the sub and is provided with sections having the outer surface thereof situated at various radii with respect to the central axis of the housing, the ratio between the minimum and the maximurn radii being at most 0.95, the large-radius sections forrning stabilizer wings, and at least part of these latter sections housing at least parts of the hydraulic rotary motor.
The hydraulic motor may be a vane-type motor having the vanes thereof slidably arranged in slots carried by the rotor. The large-radius sections then house at least part of the fluid conduits.
In another embodiment of the invention, the hydraulic motor is a vane-type motor having at least part of the fluid conduits arranged inside the rotor. The large-radius sections then house slots wherein vanes are slidably arranged.
In still another embodiment of the invention, the hydraulic motor is a Moineau-type motor. The large-radius sections are then helically shaped and enclose part of the compartments between the rotor and sta-tor housing.
In again another embodiment of the invention, the hydraulic motor comprises a rotor having a toothed outer surface co-operating with a plurality of cylindrical bodies that are positioned at regular distances from one another along the inner wall of the stator housing. Each such body is then positioned in a large-radius sec-tion of the stator housine.
It will be appreciated that for a given hole diarneter the use of a stator housing having large-radius sections, locally illcreases -the radius of thehousing wnen compared to circle cylindrical stator housings of prior art hydraulically powered drilling subs. The sections having relatively large radii act as stabilizer wings which can house parts of the hydraulic motor, whereby the compartments of the motor obtain ~3~
an increased volume per unit lengthT,~ncorllpared to prior art motors.
The stabilizer wings stabilize the sub against horizontal deflection in the hole that is being dr lled. If straight sections are used, at least three large-diameter sections should be provided in order that these sections will act as stabilizer wings. Generally four or more cr these sections will be applied, such as from four to eight sections.
If helically shaped sections are used, such as in connect;on with Moineau-Motors, the nurnber of sections is equal to the nurnber of lobes of the stator. Such stator has at least two lobes.
The invention will be described by way of example in more detail with reference to the drawings.
Figure 1 shows schematically a cross-section over a hydraulically powered drilling sub according to the invention, incorporating a sliding vane-type hydraulic motor wherein the sliding vanes are carried by the rotor thereof.
Figure 2 shows a longitudinal section of the drilling sub of Figure 1, taken over section II-II thereof.
Figure 3 shows schematically a longitudinal section over a drilling sub according to the invention of alternative design, wherein the sliding vanes are located in slots situated in the housing of the motor.
Figures 4-8 show cross-sections of the drilling sub of Figure 3, taken over sections IV-IV, V-V, VI-VI, VII-VII, and VIII-VIII respectively.
Figure 9 shows schematically a cross-section over a hydraulically powered drilling sub according to the invention, incorporating a hycraulic motor of the Moineau-type.
Figure 10 is a side view of the sub of Figure 9.
/ Figure 11 shows schematically a cross-section over a drilling sub according to -the invention, incorporating a hydraulic motor of the internal gear type.
The hydYaulica]ly powered drilling sub of Figures 1 and 2 has the vanes 1 -thereof slidably arrarlged in -the slots 2 of the ro-tor 3.
The vanes are pushed against the inner wall of the housing 4 by springs (not shown) arranged be-tween the vanes and -the bottom parts of the slots. The inner wall of the housing 4 is constituted by a wear-resistant lining 6 provided wi-th openings 7, o, 9 and 10. Fluid supply conduits 11, 12 in the housing 4 comrnunicate with the openings 8 and 10, respecti.vely, and fluid discharge condui.ts 13, 14 in the housing )~ comrnunicate with openings 9 and 7, respectively.
Th~ space betwcen the outer wall of' the rotor 3 and the inner non-cylindrical wall of the lining 6 of` housing 4 consists of~ two S parts with crescent-shaped cross-s~ction, which parts are divided into a plurality of' compartmen-ts 15 by -the vanes 1. I-t will be appreciated that the total vol~ne c,f -t'rle compartmerlts .is constant, but that thc vo~.urnc of' each compartrnen-t vrlri.-c be-tween aL,proxirnrll;e:ly ~ero to a rna~;.murn va:Lu( wherl the rotor 3 is ro-tated in the hous;ng L~
around its central axis. l~'lui.d supplied -through supply condu:its 11 and 12 wil] enter the cornpar-tments 15 tha;t are in comrnunication with the ports 8 and 10, respectively, and acti-vate the rotor 3 to rotate around its central axis. The coMpartments 15 tha-t are in comounieation with the f'luid discharge conduits 13 and 14 wil] exhaust in these conduits through the ports 9 and 7, respectively.
The supply conduits 11 and 12 via which liquid is supplied to the ports 8 and 10, respectively, communicate with passages 17 (one of which is shown in ~igure 2) in the tubular member 18 that is connected to the upper encL of the housing 4 by means of a screw thread 19. The tubular rnember 18 is provided with an int~rnal screw thread 20 for connecting the hydraulically powered drilling sub to drilling means (not shown) such as the lower end of a drill collar.
A bearing 21 is carried by the tubular member 18, and the shaft 22 of the rotor 3 is rotatably supported by said bearing 21. A cheek plate 23 w:ith wear-resistant lining 2ll is arranged be-tween -the tubular member 18 and -the rotor 3. The upper erld of the s:lots 2 housing -the vanes 1, as well as the upper end of' thc space consisting o:f compartments 15 are sealed off' by said cheek pla-te 23.
A second cheek plate 25 wi-th wear-res:i.strlrl-t l:inillg 26 is arrangc?d at the lower end of' the rotor 3 f'or closing of':f' L,he :L.owcr c~nds oL` the slots 2 and the space consist:illg of'(ompar-tmcrlts 15. I'hiS .1.owcr Clld of the rotor 3 ir; provided. wi-th a shaI't 27 that is suppc)r-ted by bear-ings 28 and 29 that are house~d in tubular mernber 31.
Two passages 32 (only one of' which is shown in broken lines) are arranged part:l.y in -the lower end of'-the housing ll anL par-tly ~3~
in the tubular member 31 ? each of s.aid passages, communicating at one end thereof with one of the discharge conduits 13 and 14, and with the other ends thereof wi-th the space 33 above the sealing member 34 in the tubular mernber 35 that is coupled to the housing 4 by means of' a screw thread 36. Tubular member 31 is being prevented from rotation with respect to the housing 4 by means of a key 37.
A splined shaft 38 cooperating with a splined opening 39 in the lower end of the rotor 3, is attached to the mernber 40 that is connected by a screw thread 41 to the dri].l shaft 42 having a central bore 43. Space 33 communicates with the central bore 43 via openings 44 in member 40. Any liquid that is leaving the compartments 15 can thus flow via drain conduits 13 and 14, channels 32, space 33, openings 44 and central bore 43 to a rotary drilling bit (not shown) that is coupled to the lower end of the drill shaft 42. Axial loads 'between the shaft 42 and the housing 4 are taken up by the thrust bearing 45 comprising a plurality of spacer rings 46 mounted on the drill shaft 43 by means of a screw ring 477 and a plurality of spacer rings 48 cooperating with the rings 46 and mounted inside the tubular member 35 by means of a screw ring 49. Cooperating surfaces of the rings 46 and 48 may be provided with wear-resistant linings (not shown) and suitable channels or passages (also not shown) may be arranged for supplying liquid to the thrust bearing 45 for cooling and lubricating purposes. This type of thrust bearing is known per se and does not require a detailed description.
As can best be seen in Figure 1 of the drawings, the cross-section of the housing 4 is such that passages 50 are present between the outer wall of the housine 4 and the inner wall of the borehole (see broken line 51). The housing 4 there'by acts as a stabilizer when the sub is being operated in the hole 51. The passages 50 are used for the return flow of the mud through the bore-hol~ 51-The four large-radius sections 52 of the housi.ng 4 form wings that stabilize the hydraulic sub and the drilli.ng bit driven thereby in the borehole, whereby horizontal deflection of the borehole is prevented, or at least minimized.
1139~
The ratio between the smallest radius of each of the sections 53 located between two of the large-radius sections 52 is at most 0.95.
By arranging the conduits 11-1~ in the large-diameter sections 53 of the housing 4 that forms the stabilizer wings, the radius of the lining 6 can be increased as compared to prior art hydraulically powered drilling subs that incorporate vane-motors with housings having cylindrical outer walls. This allows an increase of the volume of the compartments per unit length of the rotor, whereby the advantages as explained hereinbefore will be gained, In an alternative embodiment of the invention, as shown in Figures 3-8 of the drawings, the large-radius sections of the housing of the vane-motor form stabilizer wings and house the slots of the vanes. The same advantages as referred hereinabove are then obtained.
The hydraulically powered drilling sub of Figures 3-8 comprises a housing 60 (see in particular Figure 3 and Figure 6, which latter figure shows a cross-section over the motor of Figure 3 taken at the level of the middle of the rotor thereof) comprising eight large-radius sections 61. These sections are of slightly smaller radius, than the borehole 62, and each space 63 enclosed by a pair of sections 61 nearest thereto and by the borehole wall acts as a return passage for the mud in the hole 62.
Each large-radius section 61 houses a slot 6~ in which a vane 65 is slidably arranged. Springs (not shown) are arranged between the bottom of each slot and the vane,in said slot. A rotor 66 is arranged in the bore of~the housing 60, and the space between the rotor 66 and the housing 60 is divided into a plurality of compartments 67 by the vanes 65. The central axes of the rotor 66 and of the housing 60 coincide and the outer wall of the rotor 66 is shaped such that the volumes of the various compartments 67 vary when the rotor 66 is rotated. Rotation of the rotor is 'brought 113~
forward by the supply of pres.sure liquid via the charmels 68 and 69 in the rotor 66. This liquid passes through ports 70 and 71, respectively, that are arranged in the wall of the rotor 66. After passing through the cornpartments 67 in the space between the rotor 66 and the housing 60, the liquid is discharged via the ports 72 and 73, respectively, and leaves the vane motor through discharge channels 74 and 75 that are arranged within the rotor 66.
The supply channels 68, 69 and the discharEe channels 74, 75 are formed by the insert piece 76 that is situated in the central bore of the rotor 66. This insert piece 76 consists of four walls that form the supply channels 68, 69 such that the cross-section of each channel decreases in downward direction (see Figures 4-8), whereas the discharge charmels 74, 75 each have a cross-section that increases in downward direction (see Figures 4-8). Since each channel cornmunicates with a row of ports 70-73, and each row extends in longitudinal direction along a channel, the flow of liquid through each channel will be approximately equal along the length of each channel. The fluid pressure at each inlet port of the rows of inlet ports 70, 71 will therefore be substantially equal. Also, the fluid pressure at each outlet port of the rows of ou-tlet ports 72, 73 will therefore be substantially equal. As a result thereof, each blade 65 will be subjected to a uniform driving pressure over its length.
The insert piece 76 is sealingly connecied to the wall of the central bore of the rotor 66, and secured against axial as well as rotational displacements within said bore.
The slots 64 and the compartments 67 are sealed o~'f at the upper and lower ends thereof by cover elements 77, 78, respectively (see Figure 3). These elements are connected to the housi.ng 60 by a plurality of ].ocking bolts 79 passing through holes in recessed parts 80 (see broken lines) of the elements 77, 78 and screwed in screw-threaded holes arranged in the stator housing 60. A coupling element 81 provided with an internal screw thread 82 for connecting the hydraulically powered drilling sub to a drill collar is connected to the cover element 77 by rrleans of a screw thread 83.
Flement 81 is provided with a bearing 84 for supporting the upper shaft 85 of the rotor 60.
The lower shaft 86 of the rotor 60 is supported by a bearing 87 carried by the sleeve member 88 that is connected to -the cover element 78 by means of a screw thread 89. The sleeve member 88 houses a thrust bearing 90 for transmitting axial loads between the drill sha~t 91 and the housing 60. The drill shaft 91 is coupled to the lowcr end of the rotor shaf't 86 by rneans O:r a screw thread 92, and -the space between the drill shaf't 91 and -the bushine 88 is filled with lubricarlt and closed of`i' by 5eal'~ 93, 94 that are kept in place in an appropriate manner such as by snap-rines (not shown ) .
The lower end of'-the shaft 91 is provided with Q screw thread 95 f'or coupling a (not sho~m) drill bit to this shaft.
The embodimen-t of the invention shown in Figures 3-8 has the slots 64 of the vanes 65 arranged in the large-radius sections 61 f the housing 60, which sections act as stabilir/er wings. By this arrangement of the vanes, the compartments 67 have a large volume per unit length. The advantages thereof have already been explained herein-before.
Although the embodiments shown by way of example in the drawings both show a hydraulically powered drilling sub wherein the vane motor comprises rigid vanes that are slidably arranged in slots, the invention is not limited to this type of vanes. Equal good results will be obtained when applying the invention in a hydraulically powered drilling sub having a vane motor with flexible vanes. These vanes may be f'ormed by flexible sheets that are connected to the rotor (or to the housing) along onel~or~itudinal edge -thereof'. Also, such vanes may consist of rigid e]ongate elements that are hingedly connected (such as by means of' a flexible sheet) to the housing or rotor o~ the vane motor. Exarnples of flexible vanes are shown in U.S. patent specificatior1s Nos. 2,655,3ll4 and 3,301l,838; and German patent specificci-tion 1,025,359. In again another ernbodi,ment of the invention, the va,nes may be formed by cylindrical bodies that have the central axes thereof' parallel -to the cel1tral axis oI' the rotor. An exarnple of this type of motor is described in Bri,-tish patent specification 1,443,6~4.
The two embodiments shown in Eigures 1-8 oL' the draw;ngs in-corporate balanced vane motors having two sets of inle-t ports and ]o t~"o sets of outlet ports. MlLLti-balanced vane motors may be applied as well, such as mo-tors having three sets of inlet ports and three sets of outlet ports. It is observed tha-t unbalanced motors having a sing]e set, of inl.et por-ts and a single se-t of outlet ports are o:ften ]iable to jarnrning of the rotor in -the housing and -therefore not pr-f'erred.
'Lhe vanes ina~ be prec;scd f~or s~aling purposc-s against the inner wall of thc housine (whc?n the vanes are rnounted in the rotor) or againSt the outer wa].:L of the rotor (~"hen the vanes are mounted in the housing) by springs mounted between the vanes and the bo-ttom of the slots as well as -by any other Means suitable f'or the purpose.
Such means are known per se and do not need a detailed description.
Wear-resis-tant l.iners and/or coatings may be applied at -those surfaces where excessively large wearing forces will be generated.
Suitable materials for such liners and coatings as well as treating methods for increasing the resistance against wear of materials are known and these may ~be applied in the drilling sub of the present invention where such is deemed necessary. In particuLar, such wear-resistant linings may be used for covering the stabilizer wings over ~ those areas where the wings contact the borehole wall during drilling operations.
The present in-vention may further be applied to hydraulically powered drilling subs comprising one or more positive displacement motors of the Moincau-type, wherein each motor comprises a helically-shaped ro-tor that ;.s ro-tata.b]y a.rranged within a helica.lly-shapc?d stator. A plurality of' f'luid compa.rtmc?rl-ts ;s I'orinccl belween the rotor and the stator, w}l;.ch comparl;ments are disll.-~ced he]ically arouncl the central axis of the Mo:ineall-lnotor wherl th( rol;or is displaced in -the stator. DurinFr such displacernent, tllc rotor rotates around i-ts axis and simu:l.taneously orb:its aroun(l thc central .IXiS
of' the sta-tor, arld thc~-torque exer-ted on the rolor by ~the driling fluid is transferrecl ViQ a f:lexib:Lc or universal coupling to a shaft tha-t is support.ed axi.ally within the ~.ower end of thc stator housing and adapted to be connected to a drill bit.
35 F'igure 9 of the drawings shows a cross-sec-tion over a dri:Lling 1~3~2~1~
sub with a hydraulic motor of the Moineau-type, wherein a three-lobed rotor iO0 cooperates with a four-lobed stator 101.
In the embodiment shown, the rotor 100 is made of metal, such as steel, whereas the stator 101 is of flexible material, such as rubber or an elastomer rnaterial. The stator 101 is supported in a stator housing 102 having helical large-radius sections 103 as can best be seen in Figure 10 which shows a side view of the motor of Figure 9. Figure 9 shows a cross-section of the motor taken over section IX-IX of Figure 10. The sections 103 of the stator housing 102 have helical grooves 104 therebetween which allow return mud to pass alongside the housing 102 when the motor is operating in a hole 105 (seebroken line in Figure 9). The space within the large-radius sections 103 is used for housing the lobes of the stator 102 and it will be appreciated that the volume per unit length of the compartments of the Moineau-rnotor is considerably increased in this manner when comparing it with prior art Moineau-motors designed for the same drilling diameter.
The stator housing 102 is provided with a screw-threaded coupling 106 by which the Moineau-motor can be coupled to the drill string, whereas the screw-threaded coupling 107 on the rotatable shaft 108 can be connected to a rotary bit. As mentioned already hereinabo~e, the shaft 108 is coupled to the rotor 100 by means of a flexible coupling (not shown). Since all these details of the Moineau-motor are known per se, they are not discussed here in detail.
Finally, Figure 11 of the drawings shows a cross-section over a drilling sub with a hydraulic motor of the internal gear type.
This motor includes a stator housing 110 and an outer gear set consisting of rollers 111 arranged parallel to the central axis 112 of the stator housing at regl~ar distances froTn each other.
3 A part of each roller is enclosed by a cylindrical bearing formed in a recess in the wall of the stator housing 110. The rollers are rotatably arranged in the bearings and cooperate with an inner gear set formed by the toothed rotor element 1l3 that is adapted to rotate around the central axis 114 thereof and to orbit simultaneously around the central axis 112 of the stator housing 110.
~L~3~
Fluid cor.qpartments 115 are present between the rotor element 113, the stator housing 110 and the rollers 111, and pressure fluid can be supplied to -these co-mpartmer-ts ~ria the openings 116 tha-t are arranged at one end of the cornpar-tmerlts. The passage through -these openings is controllcd 'by a val~re platc- (no-t shown) that is rotatecL in conjunction wi-th the rotor 113. Sir(lilar valve con-trolled opc-nings (not sho~/n) arc f'urther provi.d(d at the other end of the comI~artments 115. 'l'ne ~alve pl.ltes cor~tro:L-thc en-try oI' high pressure f'lui.d into the compartrncntC arld -the cxhaust therco~' I'rom the compartments as a result whereof'-the rotor 11. carries out a rotational and or'bit~l movernent. The ro-tor is coupled to the drilling shaf't by (not sho~n) gear means or a (not shown) shaf't via universal coupling means, and on Movement of -the rotor, the teeth thereof co-operate with the rollers 111. A more detailed description of -this type of hydraulic positive displacement motor can be found in U.S. patent specif'ication 3,289,602 (patented 6th December, 1966, Inv. Bernard C. Hudgens, assignor to T~W Inc.~.
In accordance with the invention, the outer wall of the stator housing 110 of the motor shown in Figure 11 comprises large-radius sections 11 r that house the rollers 111 o~ the motor. Be-tween the eight large-radius sections 117 there are eight small-radius sections 110 along which return mud can flow between the outer wall of the sub and -the wall 119 o~ the borehole.
It will be appreciated that the shape of the non-c:ylindrical outer walls of the sta-tor housings that form at least par-t of the outer walls o~ the hydrau~Lically actuated drilling subs according to the i.nvention should be chosen such -that a pasca~eway of suffi.cien-t cross-section fo:r a:Llowing the f':Lowci' rc-tu1rlrrlud is lef-t 'betwren -the oll-ter wal] of -the stal;or hC)Us; n~ ar1d thc wall Or the borehole in which thc motor .is o-perc~tirlg. 'L'o th:i cn(L, the ratio between the m;.n;.rmlrn radius and -the muximl1M ru(l:ill; c~t' the outc:Lwall of the s-ta-tor housing ;hould be not l.arger tharl().95. 'L'l-~e large-radius sect;r)rls of'-the housing, Wh;.C~I f'orm the stai)il:i%c:r wi.ngs, may have a rLi.arneter that is s:Lightly less tharl the hole d;.ameter (say, betweerl 9~.0 an(l 99.6% -thercoI') wrlereus the small-~3~
radius sections situated between the wings form the passage ways for the return mud. It will be understood that the ratio between the rninimurn radius and the maximum radius of the outer wall of the stator housing is further selected in dependence on the number of wings and the si~e thereof in tangential direction with respect to the stator housing. Wnlen increasing the nwnber of` wings and/or increasing the width of the wings, lower ratios should be applied, such as between 0.ô5 and 0.75 in order to create a return mud passage of sufficient area.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A hydraulically powered drilling sub for use in combination with deepwell drilling means including a drill string and a drill bit as elements thereof, the hydraulically powered sub including a hydraulic rotary motor of the positive displacement type, the motor including a stator housing with a central axis, the housing being provided with coupling means adapted to connect the housing directly or indirectly to one of the elements of drilling means such that the central axis of the housing coincides with the axis of rotation of the drilling means, the motor further including a rotor rotatably arranged within the stator housing, coupling means adapted to connect the rotor directly or indirectly to the other element of the drilling means, fluid compartments between the inner wall of the stator housing and the outer wall of the rotor, and conduits for passing fluids into and out of the compartments, wherein the outer wall of the stator housing forms at least part of the outer wall of the sub and comprises portions having the outer surfaces thereof situated at various radii with respect to the central axis of the housing, the ratio between the minimum and the maximum radii being at most 0.95, the large radius wall por-tions forming stabilizer wings, and at least part of said large-radius wall portions housing at least part of the hydraulic rotary motor.
2. The drilling sub according to claim 1, wherein the motor is a vane-type motor having vanes slidably arranged in slots carried by the rotor, and the large-radius wall portions house at least part of the conduits.
3. The drilling sub according to claim 1, wherein the motor is a vane-type motor having at least part of the conduits arranged inside the rotor, and the large-radius wall portions house slots wherein vanes are slidably arranged.
4. The drilling sub according to claim 3, wherein the rotor comprises a body with two end parts and a central bore, said body having at least two rows of openings extending along the length of the rotor, said rows of openings alternately communicating with one of the end-parts of the rotor via conduits that are formed inside the bore by a body that is sealingly mounted inside the bore, and each of said conduits increasing in cross-section from zero to a maximum value in the direction of one of the end-parts of the rotor.
5. The drilling sub according to claim 1, wherein the motor is a Moineau-type motor, the large-radius wall portions are helically shaped and enclose part of the compartments between the rotor and stator housing.
6. The drilling sub according to claim 1, wherein the motor comprises a rotor having a toothed outer surface cooperating with a plurality of cylindri-cal bodies that are positioned at regular distances from one another along the inner wall of the stator housing, each body being situated in a hollow space of a large-radius wall portion.
7. The drilling sub according to claim 1, wherein the stabilizer wings are at least partly covered by a wear-resistant material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7932750A GB2059481B (en) | 1979-09-21 | 1979-09-21 | Hydraulically powered drilling sub for deepwell drilling |
| GB7932750 | 1979-09-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1139298A true CA1139298A (en) | 1983-01-11 |
Family
ID=10507973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000359212A Expired CA1139298A (en) | 1979-09-21 | 1980-08-28 | Hydraulically powered drilling sub for deepwell drilling |
Country Status (6)
| Country | Link |
|---|---|
| BE (1) | BE885285A (en) |
| CA (1) | CA1139298A (en) |
| DE (1) | DE3035288A1 (en) |
| FR (1) | FR2465869B1 (en) |
| GB (1) | GB2059481B (en) |
| MX (1) | MX155269A (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4620601A (en) * | 1981-09-28 | 1986-11-04 | Maurer Engineering Inc. | Well drilling tool with diamond thrust bearings |
| US4492276A (en) * | 1982-11-17 | 1985-01-08 | Shell Oil Company | Down-hole drilling motor and method for directional drilling of boreholes |
| US4665997A (en) * | 1985-07-26 | 1987-05-19 | Maurer Engineering Inc. | Pressure balanced bearing assembly for downhole motors |
| USRE33751E (en) * | 1985-10-11 | 1991-11-26 | Smith International, Inc. | System and method for controlled directional drilling |
| AU2904697A (en) | 1996-05-18 | 1997-12-09 | Andergauge Limited | Downhole apparatus |
| DE19821867A1 (en) * | 1998-05-15 | 1999-11-18 | Artemis Kautschuk Kunststoff | Downhole deep drilling motor based on eccentric mono-pump principle |
| CA2255288C (en) | 1998-12-14 | 2002-08-13 | Jay Cameron Adam Crooks | Apparatus and method for stabilized downhole drilling motor |
| CA2439331C (en) | 2003-09-02 | 2011-01-18 | William Ray Wenzel | Method of stabilizing a downhole drilling motor and a downhole drilling motor |
| GB0324744D0 (en) | 2003-10-23 | 2003-11-26 | Andergauge Ltd | Running and cementing tubing |
| US7172039B2 (en) * | 2003-10-29 | 2007-02-06 | Weatherford/Lamb, Inc. | Down-hole vane motor |
| US8733469B2 (en) | 2011-02-17 | 2014-05-27 | Xtend Energy Services, Inc. | Pulse generator |
| US20140190749A1 (en) | 2012-12-13 | 2014-07-10 | Acura Machine Inc. | Downhole drilling tool |
| US9765584B2 (en) | 2013-12-03 | 2017-09-19 | Tll Oilfield Consulting Ltd. | Flow controlling downhole tool |
| US10801264B2 (en) | 2015-08-20 | 2020-10-13 | Impulse Downhole Solutions Ltd. | On-bottom downhole bearing assembly |
| CN105840118A (en) * | 2016-05-17 | 2016-08-10 | 宁夏天地奔牛实业集团有限公司 | Upward raise-boring machine chambering and stabilizing device and upward raise-boring machine |
| PL3482031T3 (en) | 2016-07-07 | 2022-02-07 | Impulse Downhole Solutions Ltd. | Flow-through pulsing assembly for use in downhole operations |
| DE102019103577A1 (en) * | 2019-02-13 | 2020-08-13 | Gebr. Becker Gmbh | Rotary lobe pump |
| CN110331947A (en) * | 2019-06-26 | 2019-10-15 | 江苏联冠兆星石化科技有限公司 | One kind dismountable inside holding oil pipe in oil pipe |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2655344A (en) * | 1950-11-06 | 1953-10-13 | Mcdonald Hydraulic Drilling Co | Rotary bit operating mechanism |
| US3304438A (en) * | 1963-11-19 | 1967-02-14 | Sprague Electric Co | Phase shift gate drive circuit |
| FR1593999A (en) * | 1968-12-04 | 1970-06-01 |
-
1979
- 1979-09-21 GB GB7932750A patent/GB2059481B/en not_active Expired
-
1980
- 1980-08-28 CA CA000359212A patent/CA1139298A/en not_active Expired
- 1980-09-18 BE BE0/202144A patent/BE885285A/en not_active IP Right Cessation
- 1980-09-18 DE DE19803035288 patent/DE3035288A1/en active Granted
- 1980-09-18 MX MX18397180A patent/MX155269A/en unknown
- 1980-09-18 FR FR8020104A patent/FR2465869B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3035288A1 (en) | 1981-04-09 |
| FR2465869B1 (en) | 1985-09-27 |
| BE885285A (en) | 1981-03-18 |
| GB2059481B (en) | 1983-03-16 |
| DE3035288C2 (en) | 1989-02-02 |
| MX155269A (en) | 1988-02-12 |
| FR2465869A1 (en) | 1981-03-27 |
| GB2059481A (en) | 1981-04-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |