EP0377378B1 - Method and apparatus for the remote control of a drill string equipment by information sequences - Google Patents

Description

The present invention relates to a method and a device for remotely controlling drilling equipment.

Generally, the control of such equipment is done by an electric cable. However, the use of a cable represents a considerable gene for the driller because of the very presence of the cable either inside the drill string, or in the annular space between the drill string and the walls of the well. .

It has been proposed to carry out such commands by detecting a flow threshold or activation flow of an incompressible fluid, as described in patent FR-2,575,793. Such devices can have untimely trips of the member to be controlled, due to the instability of the flows in the drill string.

The present invention avoids these drawbacks and untimely tripping is no longer possible because, according to the present invention, the detection of a predetermined sequence of events relating to one or more quantities detectable at the bottom of the well is required (sequence which may also be qualified as information sequence) before triggering the desired action.

Such quantities can be in particular quantities linked to the fluid flowing in the drill string or to the mechanical connection that constitutes the drill string.

It will thus be possible to use the flow rate of fluids circulating in the drill string, the weight on the tool and / or the speed of rotation of the tool.

• émission à partir de la surface d'une première séquence d'informations conforme à une séquence prédéterminée,
• détection d'une deuxième séquence résultant de la transmission de la première séquence et en comparaison de cette deuxième séquence à une autre séquence prédéterminée,
• commande dudit équipement seulement dans le cas où il y a similitude entre ces deux dernières séquences.

More generally, the present invention relates to a method of remote control of at least one drill string equipment from an instruction issued from the surface, characterized in that it comprises the following steps:

• emission from the surface of a first sequence of information conforming to a predetermined sequence,
• detection of a second sequence resulting from the transmission of the first sequence and in comparison of this second sequence with another predetermined sequence,
• control of said equipment only in the case where there is similarity between these last two sequences.

The sequences relate to the flow of drilling fluid and include a step of reducing the flow of the value of a flow during drilling to a first level of flow, then a phase of increase in flow of said first level of flow to 'at a second level of flow, said phase having a given duration of time.

It is quite certain that this other sequence differs from the predetermined sequence transmitted on the surface only to take account of the transformations possibly due to transmission.

The sequences may also relate to at least one of the quantities of the following set: speed of rotation of at least part of the drill string, or weight of the tool.

The present invention also relates to a device for remote control of at least one drill string equipment from information emitted at the surface.

This device comprises means for transmitting information, means for detecting said information, the latter being connected to means for actuating said equipment.

The emission means are drilling fluid pumps located on the surface, the detection means include a flow meter and a unit for processing flow measurements, a clock adapted to, at least, measure the duration of a flow rise from a first level to a second level, means for comparing the detected information with predetermined information and the actuation means comprise at least a solenoid valve, controlled when the detected information coincides with said predetermined information.

The solenoid valve can put in communication, when it is energized, a reserve of oil under pressure with a chamber whose variation in volume causes the actuation of said equipment.

The device according to the invention may comprise a valve mounted on a communication between said chamber and said reserve and the valve is open when the pressure of the oil prevailing in the oil reserve is lower than the pressure prevailing in the chamber.

The equipment can be a bent element with variable angle.

The equipment can be a stabilizer with variable geometry.

• la figure 1 représente un diagramme logique correspondant à une séquence d'informations concernant une grandeur liée au débit, en l'occurence la différence de pressions entre un point amont d'un venturi et la pression au col de ce venturi,
• la figure 2 illustre un exemple de variation de la différence de pression en fonction du temps, dans le cas de la séquence de la figure 1,
• les figures 3A et 3B montrent un dispositif permettant la mise en oeuvre de la méthode selon l'invention,
• les figures 4 et 5 représentent d'autres types de séquences, et
• la figure 6 illustre schématiquement un dispositif selon l'invention.

The present invention will be better understood and its advantages will appear more clearly on description which follows of particular examples, in no way limiting, illustrated by the appended figures among which:

• FIG. 1 represents a logic diagram corresponding to a sequence of information relating to a quantity linked to the flow rate, in this case the pressure difference between an upstream point of a venturi and the pressure at the neck of this venturi,
• FIG. 2 illustrates an example of variation of the pressure difference as a function of time, in the case of the sequence of FIG. 1,
• FIGS. 3A and 3B show a device allowing the implementation of the method according to the invention,
• FIGS. 4 and 5 represent other types of sequences, and
• Figure 6 schematically illustrates a device according to the invention.

Figures 1 and 2 relate to a simple example of a sequence based on a fluid flow rate. In this example, actuation is done if the flow of fluid flowing in the drill string changes from one level to another within a given period of time.

The flow measurement is made by means of a measurement of the differential pressure Pd between the neck 1 where the pressure is designated P₁ and the upstream part 2 where the pressure is designated P₂ of a venturi 3, which presents l he advantage of a simple geometry creating little pressure drop and avoids the use of moving parts.

$\text{Pd = P₂ - P₁}$

The pressure difference between the upstream part 2 and the neck 1 of the venturi 3 is measured by two piezoresistive sensors 4 and 5, the gauge bridges of which are connected in differential mounting.

The holding range of the sensors can be from 0 to 750 bars.

Their differential measurement range can be from 0 to 40 bars.

The accuracy of the measurement may be of the order of 1%.

• l'alimentation des capteurs 4 et 5 et la réalisation de la mesure ;
• la détection d'une séquence de débit débutant par un débit nul, ou considéré comme tel Qmini, suivi par le dépassement d'une valeur-seuil Qact, réglable en surface avant la descente dans le puits. Ce dépassement de la valeur-seuil Qact devra se faire dans un laps de temps DT donné qui suit le redémarrage du débit, ce délai DT peut être de 5 à 10 minutes. Ce laps de temps DT écoulé, si la séquence n'a pas été complétée de la manière prévue, l'électronique peut être mise en veille jusqu'à la prochaine coupure de débit. Toute commande d'actionnement est alors impossible ;
• le réglage de la valeur-seuil de débit qui peut se faire sur la base de 16 positions, l'incrément entre les positions étant de 100 litres par minute pour de l'eau.

The device according to the invention may include an electronic assembly having the functions, in the case of the example of FIG. 1:

• supplying sensors 4 and 5 and carrying out the measurement;
• the detection of a flow sequence starting with a zero flow, or considered as such Qmini, followed by the exceeding of a threshold value Qact, adjustable at the surface before the descent into the well. This exceeding of the threshold value Qact must be done within a given time period DT which follows the restart of the flow rate, this time period DT can be 5 to 10 minutes. After this time DT has elapsed, if the sequence has not been completed in the planned manner, the electronics can be put on standby until the next flow cut. Any actuation command is then impossible;
• the setting of the flow threshold value which can be done on the basis of 16 positions, the increment between the positions being 100 liters per minute for water.

FIG. 2 represents a curve for variation of the flow rate Q as a function of time t.

This curve 6 corresponds to a flow sequence effectively giving rise to the actuation of the member to be controlled

The dotted horizontal line corresponds to the Qmini flow, the upper horizontal line corresponds to the Qact activation or activation flow threshold.

On this diagram, Qfor corresponds to the usual flow during drilling.

It is decided to order at the instant t₁ the device to be actuated.

The pumps are then stopped at the surface, so that the flow detected by the electronic assembly is less than Qmini.

The portion 7 of the curve corresponds to the drop in flow to the almost zero level, in any case less than Qmini. This level is reached at time t₂.

At time t₃, the pumps are restarted and at t₄ it crosses the threshold Qmini.

From this instant, the electronic system counts the time, so as to establish whether the time elapsed between the instant t₄ and the instant t₅ when the flow reached the flow Qact, is less than a predetermined time DT.

, il y a actionnement de l'organe à commander jusqu'à l'instant t₈. A partir de ce moment, il est possible de commander l'arrêt des pompes.In the case of Figure 2, it has been assumed that the answer is yes. After a delay $\text{r = t₇ - t₅}$

, there is actuation of the member to be controlled until time t₈. From this moment, it is possible to control the stopping of the pumps.

The lower part of Figure 1 shows a logic diagram corresponding to what has been described in relation to Figure 2.

The flow rate Q passing at a given instant in the venturi 3 is determined from the pressures P₁ and P₂, in particular by making the difference between these two pressures.

A first test is then carried out on the flow rate Q, by comparing it with a flow rate Qmini. The Qmini flow rate is low and may be close to zero.

In the case where the flow rate Q is less than or equal to Qmini, the clock is initialized to zero, otherwise there is no intervention on the clock.

A second test is then carried out, comparing the flow rate Q to an actuation flow rate Qact. If the flow Q is lower than the flow Qact, we return again to the first test, but with a new value of flow. Of course, the clock time has been increased.

If on the second test the flow Q is greater than the flow Qact, a third test is then carried out over the time indicated by the clock.

The value of this indication corresponds to the time it took for the flow to go from the Qmini value to the Qact value.

The third test compares this indication to a maximum delay DT.

If the time indicated by the clock is less than DT, then the flow sequence is a valid control sequence and there is actuation, for example by opening a solenoid valve.

Otherwise, the detection system should be put on standby until the detected flow rate becomes equal to or less than Qmini.

This can be obtained as shown in Figure 1, that is to say by returning to the start of the first test and allowing the clock time to increment.

Thus, it clearly appears that, during the drilling phase (having already lasted for at least a time DT) with a flow of liquid Qfor, there was accidentally an increase in the drilling flow up to the actuation flow, l actuation in itself will not be carried out, because the time to pass from Qmini to Qact will be greater than DT.

FIGS. 3A and 3B represent an embodiment of the device according to the present invention applied to the actuation of a bent element at variable angle.

According to this embodiment, a tubular element has in its upper part a thread 8 allowing the mechanical connection to a drill string or to a drill string and in its lower part a thread 9 allowing the fixing of the continuation of the train rods or drill string.

The bent element comprises a shaft 10 which can slide in its upper part in the bore 11 of the body 12 and which can slide in its lower part in the bore 13 of the body 14. This shaft has male grooves 15 meshing in female grooves of the body 12, alternately straight grooves 16 (parallel to the axis of the tubular body 12) and oblique (inclined relative to the axis of the tubular body 12), into which fingers 17 sliding along a perpendicular axis engage to that of the displacement of the shaft 10 and kept in contact with the shaft by springs 18, male splines 19 meshing with female splines of the body 14 only when the shaft 10 is in the high position.

The shaft 10 is equipped with a nozzle 20 in the low position, opposite which is a needle 21 coaxial with the movement of the shaft 10. A return spring 22 maintains the shaft 10 in the high position, the grooves 19 meshing in the corresponding female grooves of the body 14. The bodies 12 and 14 are free to rotate at the rotary surface 23, inclined with respect to the axes of the bodies 12 and 14 and composed of rows of cylindrical rollers 74 inserted in their raceways 25 and extractable through the holes 26 by removing the door 27.

A reserve of oil 28 is maintained at the pressure of the drilling fluid by means of an annular free piston 29. The oil lubricates the sliding surfaces of the shaft 10 via the passage 30. This passage may include a solenoid valve 31.

The bore 20 is carried by a tube 32 which is fixed to the shaft 10 by means of a ball joint 33. This ball joint 33 as well as the ball joint allow during movement of the shaft 10 a deflection of the tube 32. This deflection remains low, since the maximum angle obtained by the bent elements is generally a few degrees.

The shaft 10 comprises a second piston 35. This piston 35 defines with the tubular body 13 a chamber 36. The piston 35 slides in the bore 13 made in the tubular body 14. The chamber 36 communicates through the holes 37, 38 with the passage 30 comprising the solenoid valve 31 and therefore with the oil reserve 28 through the holes 39, 40 and 41.

The communication of the oil reserve 28 and the chamber 36 is carried out through the solenoid valve 31, when there is a valid control sequence, that is to say effectively corresponding to the actuation of the equipment to be ordered.

The reference 42 designates a venturi comprising a neck 43, an upstream zone 44 and a downstream zone 45, a pressure sensor 46 possibly differential, or two pressure sensors 4 and 5 as shown in FIG. 1.

This or these sensors are connected by electrical wires 49 to an electronic unit 47 which monitors the flow rates to detect the control sequence and trigger the actuation. To do this, the electronic unit 47 is connected by electrical wires 48 to a solenoid valve or to a solenoid valve 31.

The reference 50 designates an external connector which makes it possible to communicate on the surface with the electronic unit 47 without dismantling the entire device according to the invention. This connector is connected to the box 47 by electrical wires 51. It is also possible to program the electronic box or to empty the memories without dismantling the connection.

When a flow sequence is detected, the electronic unit sends, possibly after a time delay adjustable in the workshop between 0 and 60 seconds, a control signal, for the opening of the solenoid valve 31, which will take place once the flow sequence detected. This control signal can be maintained until the next stop of the flow or passage of the flow below the Qmini value.

The electronic unit can also memorize the hours at which a control signal has been transmitted.

The electronic box can be powered by a set of rechargeable or non-rechargeable batteries. The supply voltage can be 24 volts, the power required for the operation of a solenoid valve is 15 watt.

The opening of the solenoid valve 31 puts the oil reserve 28 in communication with the chamber 36.

The flow of fluid which passes through the device creates a pressure drop which causes a force tending to act on the piston 29 to expel the oil from the reserve 28 towards the chamber 36.

As long as the solenoid valve 31 is closed, this is not possible and the equipment is therefore not activated.

As soon as the solenoid valve 31 is open, there is displacement of the shaft 10 downwards and actuation of the variable angle elbow. The descent of the shaft 10 downwards takes place in a straightforward manner, due to the duse system 20 - needle 21 which, as soon as they cooperate with each other, cause the pressure drop to increase and thereby increase the efforts tending to lower the shaft 20.

The needle 21 includes a bead 52 so that, when the nozzle 20 arrives there, there is a variation in the pressure drop which results, at constant flow rate, in a detectable pressure variation at the surface, which informs the operators that the shaft 10 has reached its low position.

The rise of the shaft 10 is done by lowering or canceling the flow rate, so that the forces exerted on the pistons 29 and 35 are low enough for the spring 22 to return the shaft 10 to its high position. .

In order to limit the excitation time of the solenoid valve 31 and therefore to save electrical energy, the solenoid valve 31 may include a valve authorizing the flow of oil to the oil reserve when there is a pressure gradient in this direction and blocks flow when the gradient is in the opposite direction.

Figure 6 schematically illustrates such an arrangement.

Reference 53 designates the oil reserve and its piston. These references correspond to references 29 and 28 in FIG. 3A.

The reference 54 designates the chamber for receiving the pressurized fluid and the working piston which correspond substantially to the references 16 and 35 of FIG. 3B.

The reference 55 designates a solenoid valve equipped with accessories.

Reference 56 designates the solenoid valve itself.

The reference 57 designates a manual safety valve, the reference 58 a non-return type valve which makes it possible to empty the chamber 59 when the pressure in the reserve 60 is lower than that of the chamber 59.

The reference 61 designates a calibrated valve authorizing the flow of the reserve 60 towards the chamber 59, if the pressure difference between these two zones is greater than a critical value which can be fixed at 40 or 50 bars.

Of course, it will not depart from the scope of the present invention by applying the device according to the present invention to equipment other than a variable angle bent element. Thus, the present invention can be applied to the actuation of a stabilizer with variable geometry, such as that described in patent FR-2,579,662. In this case, the shaft 10 will be coaxial with the tubular bodies 12 and 14 and it will be useless to use the ball joint 33.

It will not depart from the scope of the present invention to use other types of sequences which may or may not combine several parameters.

• 1) débit de fluide supérieur à un seuil donné et poids sur l'outil inférieur à un seuil donné, ou alternativement supérieur à un seuil donné,
• 2) débit de fluide supérieur à un seuil donné et vitesse de rotation de la garniture comprise dans une plage donnée,
• 3) la séquence de commande peut être uniquement basée sur des variations du poids exercé sur l'outil de forage,
• 4) la séquence de commande peut être basée sur les variations du poids exercé sur l'outil de forage, mais à condition que le débit de fluide de forage soit inférieur à un débit donné qui peut être relativement faible ou nul.

Examples of combinations of parameters are given below:

• 1) fluid flow rate greater than a given threshold and weight on the tool less than a given threshold, or alternatively greater than a given threshold,
• 2) fluid flow above a given threshold and speed of rotation of the filling within a given range,
• 3) the control sequence can only be based on variations in the weight exerted on the drilling tool,
• 4) the control sequence can be based on variations in the weight exerted on the drilling tool, but provided that the flow of drilling fluid is less than a given flow which can be relatively low or zero.

The present invention makes it possible to control two different pieces of equipment from two different sequences.

FIG. 5 represents two curves 62 and 63 corresponding to two different flow sequences.

The first curve 62 corresponds, for example, to the triggering of the actuation of a variable angle elbow and the second 63 to the actuation of a stabilizer with variable geometry and that of the elbow element with variable angle.

In this example, we can consider that to trigger the command of the elbow element at variable angle, it is necessary that the flow passes from a flow Qmini to a flow greater than a given flow Qactcou in a period of time less than DT . Just as to trigger the control of the variable geometry stabilizer, it is necessary that the flow of drilling fluid passes from a flow Qmini1 to a flow greater than a given flow Qactstab in a period of time less than DT1.

, que $\text{DT = DT1}$

et que Qactstab > Qactcou
In the figure, to simplify the example, we have considered that:

$\text{Qmini = Qmini1}$

, than $\text{DT = DT1}$

and that Qactstab> Qactcou

Under these conditions, it can be seen that the flow sequence corresponding to the curve 62 which has exceeded the Qactcou flow within a period of less than DT without exceeding the Qactstab flow triggers the actuation of the elbow element at variable angle. While the curve 63 which has passed Qactstab in a time less than DT triggers the actuation of the variable geometry stabilizer and the variable angle bent element.

Such a procedure can be implemented by setting end to end a set strictly similar to that of FIGS. 3A and 3B and another derivative of FIGS. 3A and 3B, but which controls a stabilizer with variable geometry.

Use of the procedure described in Figure 5 can be done as shown below.

The actuation of the stabilizer is triggered the number of times necessary to put it in the desired position, then the actuation of the elbow element is triggered, without triggering the stabilizer, the number of times desired to put it in the desired position.

Thus, at the end of these operations, the variable geometry stabilizer and the variable angle bent element are in the desired configurations.

Figure 4 shows a trigger sequence that avoids the use of an accurate flow sensor.

The debit sequence corresponds to a succession of crossings of two thresholds Q₁ and Q₂ which must be carried out within a period of less than DT.

For example, in a period of 10 minutes, we would have to start from Q = 0, in fact Q <Q₁, then have Q> Q₂, then Q <Q₁, then Q> Q₂, then Q <Q₁, and finally Q > Q₂, this corresponds to curve 64.

.Can we have $\text{Q₁ = Q₂}$

.

In previous examples, it is sometimes necessary that the sequences include a variation of a magnitude of the whole flow rate of the drilling fluid, speed of rotation of at least part of the drill string or weight on the tool in a maximum time, you can impose a minimum time and combine these two time limits.

Thus, the desired variation should occur in a window in a predetermined time.

For example, if the flow rate is considered as a magnitude, it can be agreed that the detected sequence triggers the command only if the variation of flow rates from Qmini to Qact takes place in a period of time greater than 5 minutes, but less than 10 minutes.

Claims (7)

1. A method of remotely controlling at least one piece of drill string equipment from an instruction issued from the surface comprising the following stages:

   - emission from the surface of a first sequence of information conforming with a predetermined sequence (6, 62, 63),

   - detection of a second sequence resulting from transmission of the first sequence and comparison of this second sequence with another predetermined sequence,

   - if there is a similarity between these two latter sequences, the command is issued to the equipment,

   characterised in that the sequences relate to the flow rate of the drilling fluid and in that they include a stage whereby the flow rate is reduced by the value of a flow rate during drilling down to a first flow rate level followed by a phase of increasing the flow rate from the first flow rate level up to a second flow rate level, the phase occurring over a given time interval (DT).
2. A method in accordance with claim 1, characterised in that, apart from the drilling flow rate, the sequences relate to at least one of the following overall values: rotation speed of at least a part of the drill string or the weight on the tool.
3. A device for remotely controlling at least one piece of drill string equipment on the basis of information issued from the surface, comprising means for emitting the information, means for picking up the information, these latter being connected to means for activating the equipment, characterised in that the emission means are means for pumping fluid located on the surface and in that the detection means comprise a flow meter (42, 43) and a module for processing the flow rate measurements (47), a clock programmed to measure at least the duration of an increase in flow rate from a first level to a second level, means for comparing the information picked up with predetermined information and in that the activation means comprise at least one solenoid valve (31, 56) which receives commands when the information picked up coincides with the pre-set information.
4. A device in accordance with claim 3, characterised in that the solenoid valve (31, 56) provides communication when activated between a tank of pressurised oil (28, 60) and a chamber (36, 59) whose change in volume instigates activation of the equipment.
5. A device in accordance with claim 4, characterised in that it comprises a check valve (58) mounted on a communication route between the chamber and the tank and in that the check valve is open when the pressure prevailing in the oil tank is lower than the pressure prevailing in the chamber.
6. A device in accordance with one of claims 3 to 5, characterised in that the equipment is a variable angle elbow element.
7. A device in accordance with one of claims 3 to 5, characterised in that the equipment is a variable geometry stabiliser.

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