To drive drill bits, it is known to use downhole roller vane motors. These motors are driven by the drilling mud that is pumped down through the drill string to lubricate and cool the bit and to carry drill cuttings back to the ground surface through the annular space between the drill string and the borehole wall.

Roller vane motors with inner and outer housing and with the inlet/outlet ports in the inner housing are described in WO 93/08374. Roller vane motors with combined inner and outer housing, with inlet ports in the rotor and outlet ports in the housing are described in WO 94/16198.

In the above motors, rollers that are located in the extended position in recesses in the rotor are pushed by the drilling mud in chambers between rotor and (inner) housing from inlet ports towards outlet ports in a clockwise direction. Rollers that are not pushed by the drilling mud towards an outlet port are not subjected to the mud pressure since they have been forced into a retracted position by longitudinally extending wing deflector cams along the inner wall surface of the (in- ner) housing.

Advantages of the known roller vane motor with combined inner and outer housing compared to the roller vane motor with both inner and outer housing are its simpler construction and the greater torque per unit length of the motor.

A drawback of the known roller vane motor with combined inner and outer housing is that the pressure drop across the motor must be equal to the pressure drop across the drill bit, since these pressure drops are parallel. Moreover, the flowrate of the drilling mud across the drill bit is reduced.

The present invention provides various embodiments of roller vane motors that overcome this drawback. To this end, the roller vane motors according to the present invention possess the characteristics mentioned in claim 1. In addition, the present invention provides a special roller vane motor for use as a production motor to drive a downhole rotating pump and a special roller vane motor for use as a drilling motor with outer jacket.

Favourable embodiments of these roller vane motors and pumps are described in the sub-claims related thereto. Finally, the present invention provides a method and system for the use of such pumps.

The present invention will be elucidated below in more detail with reference to a drawing, showing in: fig. 1 a transverse sectional view from above of a roller vane motor with combined inner/outer housing according to the in- vention; fig. 2 a schematic longitudinal side view of the motor of fig. l; figs. 3 and 4 transverse sectional views from above of other embodiments of the roller vane motor of fig. 1; fig. 5 a transverse sectional view from above of part of the roller vane motor of fig. 1, showing two special configurations; fig. 6 a transverse sectional view from above of a roller vane motor for use as a drilling motor with outer jacket; fig. 7 a schematic longitudinal side view of the motor of fig. 6; figs. 8,9,10 and 11 transverse sectional views from above of roller vane pumps according to the present invention; fig. 12 and fig. 14 transverse sectional views from above of parts of roller vane motors and roller vane pumps according to the present invention, illustrating special embodiments; fig. 13 transverse sectional views from above of a roller vane motor according to the present invention, illustrating hydraulic phenomena that occur during the rotation process.

In the roller vane motor with combined inner and outer hou- sing according to the invention, the drawback of parallel pressure drop across the motor and the drill bit is elimi-

nated by locating the inlet and outlet ports in the upper and lower bearing part of the housing instead of in the rotor and in the housing, as shown in figs. 1 and 2. The roller vane motor in these figures comprises a tubular housing 1 and a rotor 2 running in bearing parts 3 and 4 at either end of said housing 1. The housing 1 is connected at its upper end to a non-rotating drill string. The housing 1 is provided with two radially inwardly projecting wall means in the form of ) longitudinally extending wing deflector cams 5 which, together with said housing 1, form a stator for the roller vane motor.

The wing deflector cams 5 together occupy about half the cir- cumference of the housing 1 and have a rising part that runs from the housing 1 towards the concentric part of the wing deflector cam 5 and a falling part that does the reverse. The rotor 2 is connected at its lower end to a drill bit. The rotor 2 is provided at its circumference with three pairs of diame- trically opposed and circumferentially spaced slots in the form of roundbottomed recesses 6, in which are disposed elongate longitudinally extending wings in the form of cylindrical rol- lers 7. The rollers 7 are movable between a retracted position in which they are fully or largely contained within the reces- ses 6 and a radially projecting position in which they partly project from the outer surface 2a of the rotor 2. Each roller is preferably made of metal, of a resiliently deformable acid- and heat-resistant plastic material, or consists of a metal core with a shell of said plastic material. A generally annu- lar space, defined between the rotor 2 and the housing 1, is divided by the two wing deflector cams 5 into chambers 8a, b.

Said chambers 8a, b are connected to outlet ports 9-in the lower bearing part 3 of the housing 1 for the passage of drilling mud therethrough to the drill bit, said outlet ports 9 being positioned at or near the rising part of the wing deflector cams 5. The upper bearing part 4 of the housing 1 is provided with inlet ports 10 for the passage of drilling mud there- through from the drill pipe above to each of the chambers 8a, b, said inlet ports 10 being positioned at or near the falling part of the wing deflector cams 5.

Because the pressure of the drilling mud that enters the cham-

bers 8a, b through the inlet ports 10 is higher than theX pres- sure of the drilling mud that leaves the chambers 8a, b through the outlet ports 9, the rollers 7 that are positioned in the chambers 8a, b are sucked outward and pressed against the space between the downstream sides 6b of the recesses 6 in the rotor 2 and the housing 1, thereby dividing the chambers 8a, b into high-pressure parts 8a and lower-pressure parts 8b. The rol- lers 71 are thus exposed to high-pressure drilling mud at their upstream side 7a, entering through the inlet ports 10, thereby exerting a clockwise turning moment on the rotor 2.

Two other pairs of rollers are pressed down into their retrac- ted position in the recesses 6 in the rotor 2 by the wing de- flector cams 5. When the rotor 2 has turned approximately 30 degrees further in the clockwise direction under the influence of the mud pressure on the first mentioned rollers 7 in the chamber parts 8a, the retracted rollers 7 will clear the wing deflector cams 5 and be resiliently restored into their pro- jecting position with their upstream side 7a exposed to the pressure of the drilling mud entering through the inlet ports 10 in the upper bearing part 4, thereby ensuring a continuous driving and rotating force on the rotor 2 with a torque sub- stantially directly proportional to the pressure difference in the drilling mud between the upstream chamber parts 8a and the downstream chamber parts 8b. The drilling mud in the chamber

parts 8b is compressed between the advancing downstream sides 7b of the rollers 71 and the respective opposing wing deflect- or cams 5 and is expelled through the outlet ports 9 in the lower bearing part 3 back to a central conduit 13 in the rotor 2. and mixes with another part of the drilling mud that flows through this central conduit 13 directly to the drill bit.

It will of course be appreciated that the rollers 7 will in practice tend to roll as the rotor 2 turns, thereby passing over any particulate matter trapped between the rollers 7 and the housing 1 or the wing deflector cams 5 without damage thereto. The central conduit 13 in the rotor 2 may be provided with a regulator, to regulate the relative amounts of drilling mud that pass to the drill bit through the chambers 8a, b of the motor and through said central conduit 13 in the rotor 2.

In the embodiment shown in fig. 3 the outlet ports 9 have been replaced by outlet ports 11 in the housing 1 and ! the ri- sing part of the wing deflector cams 5, said outlet ports 11 connecting the chamber parts 8b with the annular space 12 outside the housing 1.

In the embodiment shown in fig. 4 the inlet ports 10 have been replaced by inlet ports 14 in the rotor 2, said inlet ports 14-connecting the central conduit 13 in the rotor 2 with the bottoms of the recesses 6.

In all the above motors, the number of wing deflector cams 5 may be larger than two, spaced at equal distance along the interior wall surface of the housing 1, and the number of re- cesses 6 in the rotor 2 with matching rollers 7 may be smal- ler or larger than six. Preferably, however, the number of rollers 7 should be at least one larger than the number of wing deflector cams 5 and preferably less than twice as large.

It will be appreciated that the corners of the rising and falling part of the wing deflector cams 5 may be rounded off and that their slope should be as flat as possible, to bring about a smooth movement of rollers 7 between their retracted and extended position and vice versa. The flatness of these slopes is limited by the requirement that short-circuiting of the flow of drilling mud between inlet and outlet ports must be avoided, both in the chambers 8a, b and in the area between the concentric part of the wing deflector cams 5 and the rotor 2. The inner wall sections of the housing 1 and the concentric section of the wing deflector cams 5 must therefore each have a certain minimum width.

When travelling in their extended position on the inner wall surface of the housing 1, rollers 7 are pressed against the space between said inner wall surface and the outer surface 2a of the rotor 2. To avoid pinching of rollers 7 between said inner wall surface of the housing 1 and the downstream leading sides 6b of the recesses 6 in the rotor 2, it is advantageous to shape these downstream sides 6b such that rollers 7 are in contact with them at the outer surface 2a of the rotor 2. Likewise, to avoid pinching of rollers 7 be- tween the rising part of the wing deflector cams 5 and the

upstream trailing sides 6a of the recesses 6 in the rotor 2, it is advantageous to shape said trailing upstream sides 6a such that rollers 7 on said rising part are in contact with said upstream sides 6a at the outer surface 2a of the rotor 2. Both configurations are illustrated in fig. 5. Also, the diameter of the rollers 7 should be larger than twice the distance between the inner surface of the housing 1 and the outer surface of the rotor 2.

In the embodiments shown in fig. 6 and fig. 7 the outlet ports 11 are located in the housing 1 and the rising part of the wing deflector cams 5. These outlet ports 11 connect the chamber parts 8b with an annular space between the housing 1 and an outer jacket 15, attached to said housing 1. Via this annular space the drilling mud returns through inlet ports 16 to the space inside the housing 1 and further via the cen- tral conduit 13 in the rotor 2 to the drill bit.

It will be appreciated that a continuous central conduit 13 in the rotor 2 is only required for drilling motors if the amount of drilling mud required for the drill bit is larger than the amount required to drive the motor. If this is not the case, the central conduit 13 can be omitted or blocked somewhere half- way down the motor.

It will be appreciated that the motors may not only be used for drilling or coring purposes, but also to repair and clean boreholes. Thus, the working fluid need not exclusively be drilling mud but can also consist of other liquids such as e. g. oil or water, of a gas/liquid mixture, or a gas such as e. g. air.

Roller vane motors for drilling purposes as described above can also be used as a production motor for driving a rotating pump to produce fluids from a subterranean reservoir to the ground surface. At its upstream side the housing 1 of the pro- duction motor is then attached to a power fluid supply tube that is connected with the ground surface. At its lower side the housing 1 and the rotor 2 are attached to the housing and ro- tor of a rotating pump. Power fluid and produced fluids from a subterranean reservoir are mixed and pumped to the ground sur- face together through the annulus outside the power fluid sup-

ply tube or through a production tube parallel with or con- centric around the power fluid supply tube. In the embodi- ments in which the power fluid leaves the production motor inside the housing of the motor, provisions must be made to lead this power fluid back to the annular space 12 outside the motor. In the embodiments in which a central conduit 13 is present in the rotor 2, this central conduit 13 must be closed off or omitted.

Roller vane motors as described above can also be used as roller vane pumps. To this end, the rotor 2 must be attached to and driven by a clownhole electromotor in a direction op- posite to that of the described motor. Where present, a cen- tral conduit 13 in the rotor 2 must be closed off or omitted.

An example of a pump with axial fluid inlet and axial fluid discharge is shown in fig. 8. The construction of this pump is similar to that of the motor shown in fig. 1, with the exception that the central conduit 13 in the rotor 2 has been omitted. Fluid is sucked in from the inside of the hous- ing 1 below the pump through outlet ports 9 in the lower bear-

ing part 3, that then become inlet ports 9', and is pumped by the rollers 7 via the chambers 8a, b and the inlet ports 10 in the upper bearing part 4, that then become outlet ports 10', to production tubing above the pump and further to the ground surface. The rotation direction of the pump is shown with a curved arrow.

Another example of a roller vane pump is shown in fig. 9. The construction of this pump is similar to that of the motor shown in fig. 3, with the exception of the central conduit 13 in the rotor 2 which has been omitted. In this pump the out- let ports 11 to the annulus 1. 2 outside the housing 1 become inlet ports 11'and the inlet ports 10 in the upper bearing part 4 become outlet ports 10'.

Yet another example of a roller vane pump is shown in fig. 10.

The construction of this pump is similar to that of the motor shown in fig. 4-In this pump the outlet ports 9 in the lower bearing part 3 of the housing 1 become inlet ports 9' and the inlet ports 14 in the rotor 2 become outlet ports 14'.

The lower end of the central conduit 13 in the rotor 2 must be

closed off in this embodiment.

Roller vane pumps can also be driven by a roller vane pro- duction motor. In that case, it is advantageous to use a pump with axial fluid inlet and fluid discharge to the annulus 12 outside the housing 1, as shown in fig. 11. In this embodi- ment, fluid is sucked in through the inlet ports 9'in the lower bearing part 3 of the housing 1 and is pumped by the rollers 7 via the chambers 8a, b and outlet ports 17 in the housing 1 and the rising part of the wing deflector cams 5 to the annulus 12 outside the housing 1.

All the pumps described above can be adapted in such a way that their direction of rotation is reversed into the clock- wise direction and their rotation speed can be adjusted to a desired value by changing the speed of the electromotor or the roller vane production motor.

In a similar way as described for the motors, the shape of the rising and falling part of the wing deflector cams 5, the shape of the recesses 6 and the size of the rollers 7, related to the distance between the inner surface of the housing 1 and

the outer surface of the rotor 2, may be optimised to ensure a smooth travel of rollers 7.

As in the motors, also in the pumps described above the num- ber of wing deflector-cams may be larger than two and the num- ber of rollers may be larger or smaller than six.

In the motors and pumps that have been described in the figures 1,3,4,8,9,10 and 11 the inlet and/or outlet ports 9,9', 10, 10'debouch into the chambers 8a, b at or near the rising/fal- ling part of the wing deflector cams 5. This has the disadvan- tage that the upper or lower side of the rollers 7 temporari- ly block these ports during rotation of the rotor 2, as a re- sult of which the discharge/supply of drilling mud temporarily stops. This can be remedied by locating these ports partly or wholly behind the edge of the rising/falling part of the wing deflector cams 5. To maintain a continuous connection with the chambers 8a, b, (part of) the rising/falling part must be shortened lengthwise at the side concerned. This embodiment is shown schematically in fig. 12A for an inlet/outlet port 10, 10'. Each connection can be widened by creating additional

space behind the inside edge of the concentric part of the wing deflector cam 5. This is schematically shown in fig.

12B for an inlet/outlet port 9,9'.

An analysis of the rotation process shows that vibration problems and stalling of the rotor may occur as a result of hydraulic phenomena both in the roller vane motors and rol- ler vane pumps according to the invention. When rollers mount the rising part or run down the falling part of wing deflector cams, the volume between these rollers and prece- ding and following rollers changes. To prevent the occurrence of too high pressures between succeeding rollers, the space between these rollers must be continuously in connection with other liquid-filled spaces in the motor or pump when a roller is travelling on a rising or falling part of a wing deflector cam.

Fig. 13A shows a roller 7 that has descende from the falling part of a wing deflector cam 5 and has just reached the inside surface of the housing 1. At that moment, the volume of the chamber part 8a between this roller and the preceding roller 7

on the inside of the housing 1 doesnot decrease anymore, so that the connection with the inlet port 10 on said falling part can be restricted to the dotted line A-A.

Fig. 13B shows a roller 7 at the end of its rise on the rising part of a wing deflector cam 5. Further rotation of the rotor 2 will tilt this roller, 7 onto the concentric section of the wing deflector cam 5. While this happens, the volume between this roller 7 and the preceding roller on the concentric part of the wing deflector cam 5 decreases by V. Because a connect- ion has been established between this space and the outlet port 9 via a small adjacent concentric part of the wing de- flector cam 5, this volume can escape to the outlet port 9.

Should this connection have been restricted to the rising part of the wing deflector cam 5, then the roller 7, which is travel-- ling on the concentric part of the wing deflector cam 5, would have been pressed against the downstream side 6b of its recess 6, after which the rotor 2 would have come to a standstill as a result of the rapidly increasing pressure between both rol- lers. Thus, the shortening of the rising/falling part of a

wing deflector cam 5, in order to make connection with inlet/ outlet ports 10,10', 11,11', doesnot have to occupy the full width of said rising/falling part but must be extended to the nearby concentric part of this wing deflector cam 5, as shown in fig. 14A for an inlet/outlet port 10,10'.

With inlet/outlet ports 11,11', 17 in the housing 1, the solut- ion of problems with high/low pressure between rollers con- sists of widening these inlet/outlet ports 11,11', 17 such that they occupy a sufficiently wide section of the rising/falling part of a wing deflector cam 5, in addition to a small part of its nearby concentric part. Alternatively, each port can be split up into two ports, that cover both sides of such a wide port. This solution is schematically shown for inlet/outlet ports 11,11' in fig. 14B.

It will be appreciated that other solutions are possible to solve the problems of too high/low pressure in roller vane motors or pumps. With inlet/outlet ports at or near the rising/ falling part of a wing deflector cam 5 a solution consists for instance in making one or more grooves in the rising/fal-

ling part of these wing deflector cams 5.

In roller vane motors or pumps with inlet/outlet ports 14,14' in the rotor 2 the above-mentioned provisions do not have to be made. In these motors and pumps, the spaces between rol- lers 7 are at all times connected with other liquid-filled spaces in the motor or pump by way of said inlet/outlet ports 14,14'.

Motors and pumps according to the present invention may be used for various purposes with various fluids. The drilling motors are not only suitable for drilling and coring but also for well cleaning/repairing and the present invention inclues within its scope drilling, coring and cleaning/repairing appa- ratus wherein motors of the present invention are used, as well as methods of driving drilling, coring and cleaning/re- pairing apparatus using motors of the present invention.

The production motor and pumps are not only suitable for oil- field use but can also be used for producing drinking water, for producing hot water in geothermal projects, or for produ- cing drain water in mining operations such as for instance

surface browncoal. mi. ni. ng. They can also be employed in fire- fighting and cooling water installations on offshore plat- forms using seawater.

The invention includes within its scope therefore both oil and water production installations in which motors and/or pumps of the present invention are used as well as methods to produce water from a subterranean reservoir to the ground surface or to pump up water from a surface water reservoir using a motor and/or pump of the present invention.