EP0688938A1 - Device for the control of rotary drawworks - Google Patents

Abstract

System, esp. for a winch used for lowering or raising a load (2) in a well, comprises an electric drive motor (6), a single control unit (10 a) indicating the load's direction of travel and speed, a sensor for the speed and direction, and a processor (9) which compares the speed and direction with information provided by the sensor and determines whether an increase or reduction in speed is needed. The system also incorporates a brake (8), and the processor (9) translates orders for a reduction in speed both to the motor and the brake. It also has a clutch (7) between the winch (5) and the motor (6), also controlled by the processor (9) and designed to disengage the motor if the load's speed of travel exceeds the motor's permitted speed of rotation. <IMAGE>

Description

The present invention relates to a device for controlling an apparatus, in particular a winch used to raise or lower a load such as a drill string, in a borehole.

It is known that a drilling installation consists in particular of a drilling mast, a drive motor mounted on the drilling mast, and a drilling device able to penetrate the ground to drill a well there. .

The drilling device is generally suspended from the drilling mast by a cable which is itself wound on a motorized winch. In general, the winch is placed on the ground and a muffle returns the cable to the winch from the top of the drill mast.

The winch is driven by one or more winch motors possibly connected to the winch by a clutch system. A manually operated retarder brake also slows the winch if necessary.

Furthermore, the device generally includes a safety brake which is also actuated by hand and which is mainly used to keep the winch stationary.

The drilling device consists of a drilling tool which is connected to the drive motor by one or more rods forming a drill string whose main function is to transmit the torque of the motor to the drilling tool. training.

When advancing down the drill bit, rods are added to the drill string as it digs into the ground so that the drill bit can be held integral with the engine .

Conversely, during the ascent of the drilling tool, the rods emerging from the ground surface are successively removed from the drill string.

It is understood that, depending on the height of the drill mast, the number of rods which can be added or removed simultaneously is variable.

At a minimum, a mast should be high enough to allow the addition or removal of a single rod. In practice, it Frequently the masts allow the simultaneous manipulation of two or three rods.

Apart from the actual drilling operation, during which the speed of descent of the drill string is fixed by the progression of the drilling tool, it occurs quite frequently that the drill string must be raised and then lowered back into the well, for example to replace the drilling tool.

In such a case, the rod string must be reassembled over its entire length by dismantling the rods one by one, two to two or three to three, depending on the height of the mast, before reaching the last rod which supports the drilling tool to be replaced.

After which, to descend the new drilling tool to the bottom of the well, you have to join the rods one after the other to reconstitute the drill string.

These maneuvers lead, repeatedly, to vertically move the drill string over a length corresponding substantially to the height of the drill mast, and to stop it as many times as necessary.

This results in heavy handling for the operator who must act simultaneously on the winch motor or motors, on the clutch system and on the retarder brake, if necessary.

The applicant company has already described in FR-A-2 603 942 a method and a device aimed at simplifying these manipulations by keeping the winch engaged on a reversible motor, and by regulating the supply of the motor.

However, this solution is not entirely satisfactory during the descent phases of the drill string because it is necessary to limit the descent speed of the drill string so that the weight of the drill string does not give the winch a speed angle too great, having regard to the maximum speed mechanically admissible by the motor. Otherwise, there will be a runaway of the engine and there would appear the risk in particular of seeing the rotor of the engine explode. We would then lose control of the drill string.

The present invention aims to solve these drawbacks in particular by proposing a control device which allows the drill string to be lowered quickly into the borehole while retaining control.

• un moteur d'entraînement électrique,
• un unique organe de commande permettant d'indiquer un ordre de déplacement de la charge comprenant un sens et une vitesse désirés,
• un capteur du sens et de la vitesse de l'appareil, et
• des moyens de traitement pour comparer le sens et la vitesse de déplacement désirés de la charge aux valeurs fournies par le capteur de manière à déterminer si l'exécution de l'ordre indiqué nécessite une accélération ou une décélération de la charge, et ce, en montée ou en descente, et en déduire des instructions appropriées destinées au moteur, caractérisé par le fait qu'il comporte un frein ralentisseur et que les moyens de traitement traduisent les ordres de décélération, notamment pour les phases de descente de la charge lorsque le moteur est réversible, en instructions destinées à la fois au moteur et au frein ralentisseur, en répartissant entre ces derniers le couple résistant à fournir pour ralentir la charge, en fonction de sa vitesse instantanée.

The subject of the present invention is a device for controlling an apparatus, in particular a winch which is used to raise or lower a load, said apparatus comprising:

• an electric drive motor,
• a single control member making it possible to indicate an order of movement of the load comprising a desired direction and speed,
• a device direction and speed sensor, and
• processing means for comparing the desired direction and speed of movement of the load with the values supplied by the sensor so as to determine whether the execution of the indicated order requires acceleration or deceleration of the load, and this, by ascent or descent, and deduce therefrom appropriate instructions intended for the engine, characterized in that it includes a retarder brake and that the processing means translate the deceleration orders, in particular for the descent phases of the load when the engine is reversible, in instructions intended for both the engine and the retarder brake, by distributing between the latter the resistant torque to be supplied to slow the load, as a function of its instantaneous speed.

The device according to the invention makes it possible to maintain control of the load both during the ascent phases and during the descent phases of the load, by acting only on the control member.

In general, during the ascent phases of the load, the device is controlled by electrically controlling the motor.

On the other hand, during the load lowering phases, the device according to the invention makes it possible to act, either only on the retarder brake in the case where the motor is not reversible, or both on the motor and on the retarder brake if the motor is reversible.

Indeed, the resistive torque of the motor varies with its speed of rotation when this motor rotates beyond its maximum operating speed, just as the efficiency of the retarder brake can vary with the speed of movement of the load.

For example, it is known that the efficiency of an eddy current retarder brake decreases with its rotational speed. Also, in such a case, it is preferable to slow down the load during its rapid displacement mainly by means of the retarder brake, then, gradually, to bring the engine into play as the load slows down, to finally control only the engine.

In a preferred embodiment of the invention, the device further comprises a clutch system which connects the device to the engine and which is controlled by the processing means.

In this embodiment, the processing means determine the instructions capable of causing the motor to disengage when the speed of the device exceeds the speed of rotation mechanically admissible by the motor.

In a phase of slowing down of the load during its descent at high speed, the engine being disengaged, only the retarding brake is initially actuated to slow the load to a speed mechanically admissible by the engine, then the engine is engaged on the device and the slowdown by distribution of forces between the engine and the retarder brake as described above can take place.

It is understood that the device according to the invention is particularly well suited to the control of a winch of a drilling installation.

Indeed, the length of each drill rod, about 10 meters, is such that it is advantageous to be able to let go of the drill string to make it descend under the action of gravity.

Under these conditions, the time required to lower the drill string from a height of 10 meters is approximately 2 seconds, while by acting only on the engine, it would take approximately 15 seconds.

The time saving is moreover all the more important that the drilling mast is high, because such a mast makes it possible to bring down the drill string of several tens of meters at each maneuver.

• la figure 1 représente schématiquement une installation de forage utilisant un dispositif selon un mode de réalisation de l'invention,
• la figure 2 est un tableau illustrant différents cas possibles rencontrés par le dispositif de commande en fonction d'ordres donnés par l'organe de commande et des valeurs fournies par le capteur de vitesse angulaire du treuil,
• la figure 3 représente un exemple d'une succession de cas possibles au cours de manoeuvres du train de tiges, et
• la figure 4 est un schéma synoptique des moyens de traitement permettant le contrôle du treuil.

In order to better understand the invention we will now describe an embodiment given by way of nonlimiting example with reference to the accompanying drawing in which:

• FIG. 1 schematically represents a drilling installation using a device according to an embodiment of the invention,
• FIG. 2 is a table illustrating different possible cases encountered by the control device as a function of orders given by the control member and of the values supplied by the angular speed sensor of the winch,
• FIG. 3 represents an example of a succession of possible cases during maneuvers of the drill string, and
• Figure 4 is a block diagram of the processing means for controlling the winch.

The drilling installation shown in FIG. 1 comprises a drilling mast 1 to which a drill string 2 is suspended by means of a cable 3.

A block 4 returns the cable 3 to the drum of a winch 5.

For the sake of clarity, the motor for rotating the drill string 2 has not been shown.

The winch 5 can be rotated by an electric motor 6, which is reversible here, by means of a clutch system 7 placed between the winch 5 and the motor 6.

A retarder brake 8, for example an eddy current retarder brake, is also integral in rotation with the winch 5.

Processing means 9, connected to a control member 10, make it possible to control the vertical movement of the drill string 2.

As indicated by the arrows 11 and 12, the processing means receive information from a sensor, not shown, of the angular speed of the winch 5 and of the control member 10.

The controller 10 translates ascent and descent orders given by an operator. In the example illustrated, a lever 10a can be moved to the right or to the left to indicate an order of movement of the drill string up or down. The angle of the handle relative to its central position corresponds to the speed of movement desired for the operation.

As indicated by arrows 13, 14 and 15, the processing means control the engine 6, the clutch system 7 and the retarder brake 8.

Furthermore, the device comprises a band or disc brake, not shown, which serves as a parking brake when the drill string must be kept stationary and as a safety brake if necessary.

To implement the method according to the invention, the speed V _adm of the winch corresponding to the maximum speed mechanically admissible by the electric motor 6 was determined in advance.

In Figure 2, there is shown a table with two entries comprising sixteen boxes.

The vertical entry of the table corresponds to the orders given by the control member 10.

These orders are classified into four categories which are each shown diagrammatically by a drawing of the control unit.

From top to bottom, we find: the climb orders, the stop order, the descent orders at winch speeds lower than V _adm and the descent orders at winch speeds greater than or equal to V _adm .

The horizontal input corresponds to the values supplied by the angular speed sensor of the winch, which translates the behavior of the drill string.

This behavior is classified into four categories similar to the four preceding categories, namely ascent, stop, descent at a speed lower than V _adm and descent at a speed higher than V _adm .

signifie que le treuil est débrayé du moteur,
   I = I_s > 0 signifie que le moteur est commandé électriquement dans le sens de la montée de la charge,
   I = I_s < 0 signifie que le moteur est commandé électriquement dans le sens de la descente de la charge.
   F signifie que le frein ralentisseur est actionné,
   

signifie que le frein ralentisseur n'est pas actionné.Depending on these two inputs, the processing means 9 encounter one of the cases indicated in the table, in which:
E means that the winch is engaged on the engine,

means that the winch is disengaged from the engine,
I = I _s > 0 means that the motor is electrically controlled in the direction of the load rise,
I = I _s <0 means that the motor is electrically controlled in the direction of lowering of the load.
F means that the retarder brake is applied,

means that the retarder brake is not applied.

For example, when the drill string descends rapidly at a speed greater than the speed V _adm admissible by the electric motor 6, while the control member indicates a stop command, we are in the case ⑧, c ' that is to say that the motor is disengaged from the winch, that it is not electrically opposed to the movement of the load and that the retarder brake is actuated.

In FIG. 3, an example of a succession of cases has been shown as a function of orders of movement given by an operator.

In this figure, each transition from one case to the next is caused by the modification of the order indicated by the control member, or a change in behavior of the drill string.

Each transition arrow indicates the input parameter which is at the origin of the change of case.

Initially, the drill string is stationary and the controller indicates an order to stop the drill string. We are in case ⑥.

The user places the control member in the climb order position.

In accordance with the invention, the processing means pass to case ② which corresponds to the input parameters (order: climb , drill string: stationary ).

In case ②, the winch is engaged on the motor, the motor is supplied electrically in the direction of the rise of the drill string and the retarder brake is released.

As a result, the drill string moves upward, causing the transition to case ①.

The operator then places the control member in the stop position.

We then go to case ⑤, that is to say that the motor is supplied in the resistive direction and the retarder brake is actuated. The distribution of forces between the retarder brake and the motor is automatically regulated. This causes the drill string to stop and go to case ⑥.

We can, in the same way, read the following transitions which are represented in FIG. 3.

In Figure 4, there is shown the processing means of the device described.

In this figure, we find the control member 10, the engine 6, the clutch mechanism 7, the retarder brake 8 as well as the winch 5.

The axis Δ materializes the drive shaft of these members.

The actuator 10 is connected, on the one hand to a first comparator 16 intended for controlling the motor, and on the other hand to a second comparator 17 intended for controlling the retarder brake.

The comparator 16 receives as input a reference value V _ref indicated by the control member 10 and corresponding to an ascent or descent command at a given speed desired by the user.

The comparator 16 also receives a signal V _word in return from the motor 6, which indicates the operating conditions of the motor.

Such a signal can for example be provided by a sensor of the engine speed.

By comparing the values V _ref and V _word by difference, the comparator 16 establishes an appropriate control signal to cause the motor to run at the desired speed.

The signal from comparator 16 is amplified by an amplifier 18.

The value V _ref is also sent to the comparator 17, which also establishes the difference with the value V _f from the sensor 19 indicating the speed of rotation of the winch.

By comparison between these two values, the comparator 17 establishes a control signal for the retarder brake which is amplified by an amplifier 20.

In this way, when the winch 5 rotates at a speed too high relative to the desired speed corresponding to the value V _ref , the retarder brake 8 is actuated to slow down the winch.

If the direction of movement indicated by the control member 10 is different from the direction of rotation of the winch, or if the desired speed is lower than the speed of rotation of the winch, it is of course necessary to brake. On the other hand, the retarder brake is not actuated in the case where the desired direction of movement corresponds to the direction of rotation of the winch and where the desired speed of movement is greater than the speed of rotation of the winch.

These conditions are expressed by the two inputs 21 and 22 of the OR gate 23, which controls a switch 24 which acts as an AND gate with the signal from the comparator 17.

To avoid malfunctions which could result from a lack of precision in the sensors and comparators of this system, an additional connection 25 is provided between the signal from the comparator 16 controlling the motor 6, and the comparator 17 controlling the retarder brake 8 .

The risk is in fact that, for lack of precision, the comparator 17 considers the signal V _ref as formulating a braking order, V _ref being seen from the comparator 17 very slightly less than V _f , while the comparator 16 considers the signal V _ref as formulating an acceleration order, V _ref being seen from comparator 16, slightly greater than V _word .

The engine and the retarder brake would then operate in a contradictory manner.

The purpose of the signal coming from the link 25 is to evade the reference value V _ref coming from the control member 10 to ensure that the release of the retarder brake takes place as well as possible and in synergy with the engine in the case where the latter is controlled in the resistive direction.

Conversely, when the motor is controlled in the motor direction, the signal coming from the link 25 is added to the value V _ref to avoid unexpected braking.

The clutch mechanism 7 is controlled by a comparator 26 which receives, on the one hand the value V _f from the speed sensor 19 of the winch, and on the other hand the return value V _word from the engine 6.

By comparing these two values, the comparator 26 establishes by difference a control signal whose absolute value, obtained for example by a diode bridge 27 and is transmitted to a second comparator 28.

This comparator 28 receives as input a clutch threshold value V _s which corresponds to the speed difference between the engine and the winch beyond which it is not possible to engage under penalty of overtorque imposed on the engine or cable relaxation.

Below this threshold value V _s , the clutch mechanism 7 engages the engine 6 on the winch 5, the signal from the comparator 28 being amplified by an amplifier 29 and transmitted to the clutch control 30.

The speed of rotation of the winch V _f is also continuously compared with a value v _adm corresponding to the maximum speed of rotation mechanically admissible by the motor.

If this speed is exceeded, it is necessary to disengage the motor, otherwise it will deteriorate.

To this end, a comparator 31 establishes the difference between the two aforementioned values and, via an amplifier 32, sends a signal to the clutch control 30.

Thus, by automatic regulation, it is possible to control both the engine, the retarder brake and the clutch mechanism.

It is clear, in this example, that the operation of the drill string is greatly facilitated by the device according to the invention which makes it possible to lower the drill string at a high speed while retaining control of this movement.

It is understood that the embodiment which has just been described has no limiting character and that it can receive any desirable modifications without departing from the scope of the invention.

In particular, although the invention has been described on the example of a winch, it is clear that one could use any other device capable of raising or lowering a load, to implement the invention.

Claims (3)

Device control device, in particular a winch used to raise or lower a load, said device comprising: - an electric drive motor, - a single control member (10 a ) making it possible to indicate an order of movement of the load (2) comprising a desired direction and speed, - a sensor (19) of the direction and speed of the device (5), and - processing means (9) for comparing the desired direction and speed of movement of the load (2) with the values supplied by the sensor (19) so as to determine whether the execution of the indicated order requires acceleration or a deceleration of the load (2), and this, up or down, and deduce therefrom appropriate instructions intended for the motor (6), characterized in that it comprises a retarder brake (8) and that the means for processing (9) translate the decelaration orders into instructions intended for both the motor (6) and the retarder brake (8), by distributing between them the resistant torque to be supplied to slow down the load (2) as a function of its speed instant. Device according to claim 1, characterized in that it comprises a clutch system (7) between the device (5) and the engine (6), the clutch system (7) being controlled by the means of treatment (9) for disengaging the motor (6) when the speed of the device (5) exceeds the mechanically admissible speed of rotation of the motor (6). Use of the device according to any one of claims 1 and 2 for raising or lowering a drill string in a borehole.

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