Method and apparatus for measuring a parameter within the well with a plug

METHOD AND DEVICE FOR MEASURING A PARAMETER

IN THE WELL WITH A PLUG

Field of the invention

The present invention generally relates to a device and methods for making a well. In particular, the present invention relates to a device and methods for measuring a parameter of the well with a cementing device in the wellbore as a cement plug. More particularly, the present invention relates to a device and methods for communicating along the entire annular space of the cementing plug to the surface.

Description of the prior art

After a well has been drilled, standard practice in the petroleum industry is to line the well with metal casing. An annular zone 20 is thus formed between the casing and the formation. A cementation operation is then carried out in order to fill the annular zone with cement. The combination of cement and casing strengthens the wellbore and facilitates isolation of certain areas of the formation behind the casing for the production of hydrocarbons. It is common to use more than one string of casing in a wellbore. In this regard, a first string of casing is secured in the wellbore when the well is drilled to a designated first depth. The first string of casing is suspended from the surface, and then from the cement

ΜΑ »31333Β1

SR 36626 DB 2 is sent into the annulus behind the casing. The well is then drilled to a second designated depth, and a second string of casing, or jacket, is extended into the well. The second string 5 is fixed at a depth such that the upper part of the second string of casing covers the lower part of the first string of casing. The second liner string is then attached or suspended to the existing casing. Then the second string 10 of casing is also cemented. This process is usually repeated with additional reams of liner until the well is drilled to full depth. In this way, the wells are generally formed of two or more rows of casing of ever decreasing diameter.

The process of cementing a jacket in a wellbore generally involves the use of jacket cementing plugs and drill pipe valves. The plugs generally define an elongated elastomeric body used to separate pump fluids in a wellbore. A liner cementation plug is generally placed inside an upper portion of the liner, and is lowered into the wellbore with the liner 25 at the bottom of a work string. The liner cementation plug has radial wiping elements for contacting and wiping the interior of the liner as the plug descends into the liner. The liner cementation plug 30 has a cylindrical bore therethrough to allow passage of fluids.

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In general, the cementing operation requires the use of two plugs and valves. When the cement is ready to be distributed, a first valve is released in the work train. Cement is pumped behind the valve, thereby moving the valve into the drop hole. The valve acts as a barrier between the cement and the drilling fluid to minimize contamination of the cement. As the valve moves through the downhole, it rests against a first liner cementation plug and closes the internal bore through the first plug. Hydraulic pressure from the cement above the valve causes the valve and plug to dislodge from the liner and be sucked into the bottom of the liner together. In the bottom, the first plug rests against a floating valve, thereby closing off a flow of fluid through the floating valve. Pressure builds above the first plug until it is sufficient to cause rupture of a membrane in the first plug. Then the cement flows through the first plug and the float valve and back up into the annular space between the wellbore and the liner.

After a sufficient volume of cement has been placed in the wellbore, a second valve is deployed. Drilling mud is pumped from the backlog of the second valve to move the second valve into the bottom of the work string. The second valve moves into the descent hole and rests against a second liner cementation plug.

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Hydraulic pressure above the second valve forces the second valve and the second plug to dislodge from the liner, and they are sucked into the bottom of the liner together. This forces the cement in front of the second plug to move out of the liner and into the annulus. This movement of the cement in the annular space continues until the second plug comes to rest against the floating valve. Then the cement can harden before the floating valve is removed.

The cementing operation may also require the use of a single plug and valve: the first plug or the first valve of the previous operation being removed.

During the cementing operation, it would be very useful to be able to measure the temperature and pressure in the downhole at various points along the wellbore as the plug is moved and also in the annulus then. that the cement hardens. Currently, this cannot be done since there is no robust telemetry method that is convenient with conventional operating practices. Some prior art has attempted to describe a device for measuring parameters from the cement plug.

US Pat. No. 6,634,425 describes a cement plug with a sensor transmitting the measured value to a surface location via wired or wireless transmission means, such as, for example: a wire cable, an optical fiber or acoustic waves. The problem is

I -31333Β1 i SR 36626 DB 5 that the cementation plug cannot be deployed over long distances and measurements are only limited to a value measured on the plug, therefore inside the casing and at the exact position of the 5 cap.

European Patent Application No. 06290801.7 by the same applicants describes a way of deploying an optical fiber from a surface to a backing sleeve by attaching a fiber reel to the upper plug, the upper plug being sucked into the backing sleeve. casing by displacement fluid. In fact, the system is an improvement on the method of measuring parameter in the wellbore; the system is insufficient because, when a sensor is used on the top plug or on the fiber, measurements are still limited to inside the casing.

There is a need, therefore, for a convenient device for measuring a parameter inside a wellbore casing, as well as in the annulus of the wellbore. In this way, there is a need for a device which correctly and precisely determines parameters informing the hardening of the cement.

Summary of the invention

According to one aspect of the invention, the invention provides a system for measuring a parameter in a well, comprising: a first device comprising a first coil of first line of coiled optical fiber (or fiber) capable of being unwound from. the first coil, at least a first sensor capable of .31333Β1

SR 36626 DB

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measuring the parameter of the well, wherein information relating to said parameter can be transmitted to the device line through the first optical fiber; a second comprising a second coil of second capable of being wound optical fiber.

unwinding of the second second optical fiber reference; a light connected to the or detecting coil, one end of the at a transmission or reception point being fixed from the device reference point and capable of generating a light pulse through the second optical fiber line; and means for passing said pulse of light between the first and second lines of optical light receiving fibers. The transmitter or transmitter / receiver which is not limited only to visible light.

other electromagnetic radiation including ultraviolet radiation (near uv (wavelength of 380 to 200 nanometers); and / or far uv or vacuum (200 to 10 nanometers; FUV or vuv); and / or extreme uv at 31 nanometers; EUV or xuv)) and infrared radiation (preferably 1260 to 1360 nanometers in O-band; and / or 1360 to 1460 nanometers in band

E; and / or from 1460 to 1530 band nanometers

S; and / or from 1530 to 1565 band nanometers

VS ; and / or from 1565 to

1625 band nanometers and / or

1625 at

1675 band nanometers

U) are included in

The light transmitter / receiver.

The two optical fibers also operate at the same wave as the transmitter or receiver of light. Preferably, the first and second fibers are both identical.

same length

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Preferably, the sensor is a miniaturized self-powered sensor. The associated electronics are small and of low consumption: a sensor with a limited volume and a power supply limited to a minimum volume. For example, the sensors can be of the MEMS type. Preferably, the sensor is self-sufficient in terms of power. For example, the sensors can be sensors of the same optical type used in the optical fiber line;

when an optical signal is sent to the optical sensor, the signal is reflected by said sensor informed of the measured physical parameter. For example, the sensor is a temperature sensor and / or a pressure sensor of the family of Bragg grating sensors. Preferably, the system comprises several sensors distributed over the first optical fiber line, advantageously sensors of the Bragg grating type. The main advantage is that no complex or unwieldy electronics or power supplies are needed to support the sensor. All the electronics and analysis part is at the reference point, a signal is sent from the reference point to the integrated sensor, the reflected signal sat at the reference point is analyzed and gives information about the physical parameter measured near the sensor. The sensor can measure: a temperature, a pressure, a pH, a density, a resistivity, a conductivity, a salinity, a concentration of carbon dioxide, a concentration of asphalt. The point of reference is preferably at the surface.

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The system of the invention applies to a device such as a valve or a plug, but other embodiments can be realized. The coils have a diameter of between 20 and 50 millimeters, and preferably between 30 and 35 millimeters for a light pulse wavelength of 1310 or 1550 nanometers.

According to another aspect of the invention, the invention provides a system for measuring a parameter in a well, comprising: a first device comprising a first spool of first optical fiber line, in which a first part of the first optical fiber line is wound up and a second part of the first optical fiber line is unwound in an annular space, at least one first sensor placed on said second part and capable of measuring the parameter of said annular space, wherein information relating to said parameter can be transmitted by the first optical fiber; a second device comprising a second coil of a coiled second optical fiber line capable of being unwound from the second coil, one end of the second optical fiber being fixed at a reference point; a light emitting and receiving device linked to the reference point and capable of generating and detecting a light pulse through the second optical fiber line; and an exchange device for transferring said pulse of light between the first and second lines of optical fiber or the second and first lines of optical fiber.

ΜΑ 3333Β1

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Preferably, the first device is deployed in a jacket, such as for example a casing shoe. The first spool is then in a sleeve pitch. Furthermore, a first and / or a second device can be deployed in a plug or a valve.

According to yet another aspect of the invention, the invention provides a system for measuring a parameter in a well, the well comprising an annular space, the system comprising: a device comprising a first spool of the first optical fiber line, in which a first part of the first optical fiber line is wound up and a second part of the first optical fiber line is unwound in the annular space, at least a first one sensor placed on said second part and capable of measuring the parameter of said annular space, in which information relating to said parameter can be transmitted by the first optical fiber; a light emitting and receiving device connected to said first optical fiber and capable of generating and detecting a pulse of light through the first optical fiber line; and a communication device for transferring said pulse of light between the first optical fiber line and the surface.

Preferably, the annular space is between the formation and the casing, however an annular space between two liners can also be used. Preferably, the communication device

٧ΙΑ 31333Β1

SR 36626 DB consists of a second device as presented above.

The invention also provides a method for measuring a parameter in a well, comprising the step of: (i) unwinding a first spool from a first wound optical fiber line positioned on a first device; (ii) unwinding, from a reference point, a second coil of a second wound optical fiber line positioned on a second device; (iii) transmitting or receiving from the reference point a pulse of light through the second optical fiber line; (iv) exchanging said pulse of light between the first and second fiber optic lines; and (v) detecting, with said light pulse, the parameter and transmitting it over the first optical fiber line.

Said method is used with systems as presented above. Preferably, the exchange step is also performed by bringing the first and second devices together. In a first embodiment, the exchange step is performed by interconnecting the first and second lines of optical fiber. And in a second embodiment, the exchange step is carried out by transforming the light pulse from an optical fiber line into an electromagnetic or acoustic signal, transferring said signal into the well and transforming again said signal as a pulse of light in the second fiber optic line.

The invention also provides in a further aspect a method for communicating a * ، 31333Β1

SR 36626 DB 11

A parameter in a well, comprising the step of: (i) unwinding a first spool of a first wound optical fiber line positioned on a first device; (ii) unwinding, from a reference point 5, a second coil of a second wound optical fiber line positioned on a second device; (iii) transmitting or receiving from the reference point a pulse of light through the second optical fiber line; (iv) exchanging said pulse of light between the first and second fiber optic lines; and (v) transmitting the light pulse through the first fiber optic line; and (vi) thereby communicating said parameter between the first and second optical fiber lines.

Said method is also used with systems such as those present above. Preferably, the exchange step is also performed by bringing the first and second devices together. In a first embodiment, the exchange step is performed by interconnecting the first and second optical fiber lines. And in a second embodiment, the exchange step is performed by transforming the light pulse from an optical fiber line into an electromagnetic or acoustic signal, transferring said signal into the well and transforming from again said signal into the light pulse in the second optical fiber line.

The invention finally provides according to a further aspect, a method for communicating a parameter in a well, the well comprising an annular space, the method comprising the step of:

'31333Β1

SR 36626 DB (i) unwinding in said annular space a first spool of a first wound optical fiber line positioned on a first device in the drop hole; (ii) transmitting or receiving a pulse of light through the first optical fiber line;

(iii) communicating said pulse of light between said first line of optical fiber from the first device and the surface. Preferably, the method further comprises a step of detecting with said light pulse a parameter in the annulus and transmitting it over the first optical fiber line.

Brief description of the drawings

Other embodiments of the present invention can be understood with the accompanying drawings:

Figure 1A shows a diagram illustrating the system in a first embodiment according to the invention.

Figure 1B shows a diagram illustrating the system in a second embodiment according to the invention.

Figures 2Α to 2D show a diagram illustrating the steps of the method according to the invention for the system

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ΜΑ '31333Β1

SR 36626 DB 13 guide 8. The guide shoe 8 comprises a support sleeve 8Α with a floating valve. The casing forms an annular space 9 between the casing 2 and the formation 6.

The system according to the invention consists of a first device implemented here as a guide shoe 8, which comprises a first coil 41 of a first line of wound optical fiber 11. The first coil 41 is placed here in the support sleeve 8Α. Further, the first optical fiber line 11 can be unwound from the first spool 41.

The first optical fiber 11 is unwound directly into the annular space 9, as shown in FIG.

IA. However, for other embodiments, the first coil 41 can be placed elsewhere; the first optical fiber 11 can be deployed at

Inside the casing 2 and can also pass through the guide shoe 8 into the annular space

9. The first device also comprises at least a first sensor 51 capable of measuring a parameter of the well. Advantageously, the parameter of the well is measured in the annular space 9. This parameter can be by way of example: the temperature, the pressure, the pH, the density, the resistivity, the conductivity, the salinity, the concentration of O or of asphalt, or other similar parameters informing of the hardening of the material. cement, well integrity, or well productivity. The first sensor 51 is preferably placed at the end of the first optical fiber 11 or on the first optical fiber which is unwound. The first optical fiber 11 is such that information concerning the parameter measured by the

Μα '31333Β1 ا SR 36626 DB 14 first sensor 51 can be transmitted by the first optical fiber, thus the optical fiber line is linked to the sensor and constitutes means of communication.

The system of the invention also consists of a second device implemented, in FIG. 1A, in a plug 20. The plug 20 is shown moving along the casing 2 by means of a wellbore fluid. A second line of optical fiber 10 or fiber which is wound on a second spool 40 is attached to an upper portion of the plug; in practice, the second coil is attached or fixed by a single point of suspension 5 which corresponds to one end of the fiber or by a part of the second coil. The second spool can also be mounted in a housing or cassette. The important thing is that when the plug can move along the wellbore, the second spool and the plug are interdependent, but the fiber can be unwound from the second spool. At the other end of the second fiber, the fiber is attached or secured at a first position 4, or reference point. As will be understood, the second fiber is unwound from the second spool only by moving the plug to a second position 4 ', which corresponds to a dynamic point. An upper part 10Α of the second fiber corresponds to the unwound fiber (between the first position and the second position) and a lower part 10Β of the second fiber corresponds to the coiled fiber, still in the second spool. Preferably, the first position 4 is placed at

<img file="MA31333B1_D0003.tif" />

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SR 36626 DB 15 inside a cementing head 3, which is a static point on the surface 7. From this first position, the second fiber is linked to a light emitting or receiving device 12 through

Through a through-hole: the low pressure side being connected to the device 12 and the high pressure side being connected to the second optical fiber line 10. The light emitting device can generate a pulse of light by. the second line of optical fiber. The light receiving device can detect a light pulse through the second optical fiber line.

Finally, the system of the invention comprises means 61 for exchanging the pulse of light between the first optical fiber line 11 and the second optical fiber line 10. Said means can be direct interconnection means, such as for example a system of connectors which can be wet mated; on the other hand, indirect exchange means of a system of the wired or wireless type can be used, the optical signal being transformed into an electrical signal transferred via a cable or elements of the well such as casing, or in an acoustic signal or in an electromagnetic signal such as radio frequencies transferred through wellbore fluids or well components. The means 61 are therefore placed near the first coil 41 and connected to the end of the first optical fiber line 11 and also placed near the '31333Β1.

SR 36626 DB 16 second coil 40 and connected to the end of the second fiber optic line 10.

A wet matable optical fiber connector is a wet matable connector system which provides a connection between two lines of optical fiber. Each first and second device includes a half part of the connector, a pin and a female part for interconnection. For example, the wet matchable optical fiber connector may be of the type described in US Patent 7004638 incorporated herein by reference. On the other hand, for example, when the first and second devices are cementing plugs, perfect alignment of the pin and female parts for connection is ensured through the tubing guide. Further, for debris protection, the connector features an integrated debris management system, which incorporates a ramp profile on the receptacle unit (facing upward) and large vents in the housing. receptacle alignment sleeve. During mating, the plunger effect of the nose of the plug entering the receptacle ejects debris of mud, sand and silt through the connector interface profiles, allowing a tight fit between mating connectors, before mating. final engagement.

The wireless system is for example a radiofrequency transmitter / receiver controlling a source of light and a photoreceptor at the end of the two fibers. This type of radio frequency transmitter / receiver is

VIA ♦ 31333Β1 i SR 36626 DB 17 described in US patent application 60/882 358 by the same applicants and incorporated herein by reference.

FIG. 1B is a view of the system in a second embodiment deployed in the cased wellbore 1 in formation 6. The system according to the invention consists of a first device implemented here as a plug 21. , which comprises a first coil 41 of a first line of coiled optical fiber 11. The first spool 41 is placed here in the bottom of the plug 21. In addition, the first optical fiber line 11 can be unwound from the first spool 41. The first optical fiber 11 unwinds by passing through the guide and directly into the annular space 9, as shown in FIG.

IB. However, in other embodiments, the first coil 41 may be placed elsewhere, for example the plug may include a hole passing entirely through the plug, the first coil being placed therein. Furthermore, in other embodiments, the first optical fiber 11 can be deployed inside the casing 2 and can also pass inside the guide shoe 8 in the annular space 9. The other features of the system are the same as for the embodiment shown in Figure 1A.

Other preferable embodiments are shown here, applying to the embodiments of Figure IA or Figure IB. Preferably, the second device is of the type presented in European Patent Application No. 06290801.7 of the same.

ΜΑ '31333Β1

٠) SR 36526 DB 18 applicants. In this way, the light emitting or receiving device is an optical time domain reflectometer (OTDR) type light emitting and receiving device. LOTDR is an instrument which can analyze the loss of light in a fiber. The principle of operation is to inject a short intense laser pulse into the fiber and to measure the backscatter and reflection of light as a function of time. Preferably, the OTDR 10 operates at a wavelength of 1310 nanometers.

Preferably, the first 41 or the second 40 coil of coiled optical fiber line is made in such a way that the coils of the fiber ensure that the fiber can be simply unwound from the coil by applying minimum tension to the coil. of fiber. The windings must allow unwinding at low or high speed, with low or high density of surrounding fluid. In addition to the way in which the fiber is wound and the winding thereof, additional means for fixing or gluing the fiber windings can be used: special glue, physical or chemical treatment of the fiber. On the other hand, the fiber can be further treated so that it is chemically resistant and able to withstand strong abrasion of solid particles flowing at high speed through the wellbore for a certain period of time (usually 12 hours). For this purpose, the fibers 30 may be specially treated or may be wrapped in a protective sleeve. In addition, the

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SR 36626 DB 19 spool may be associated with a distribution box or cassette which supports the winding of the fiber. The case or cassette can be directly attached or fixed to the stopper.

The sensor 51 is, by way of example, an optical sensor of the Bragg grating sensor type for measuring the temperature. Bragg grating sensors are made by modulating the refractive index of a fiber optic line around its nominal value. They function as selective reflectors for the Bragg wavelength λ_Β defined by the following relation: λ_Β = 2.Π.Λ; where n is the refractive index of the fiber and A is the wavelength of the index modulation. A being a linear function of the temperature, the measure of the Bragg wavelength λ_Β is a convenient way to measure Bragg grating temperature generally at 1 degree Celsius. The main advantage of this technique is that the measurement is performed remotely at one end of the fiber and does not involve a bulky and expensive downhole system. In this way, the sensor 51 is implemented in a part of the fiber line which has been intentionally modified structurally. Furthermore, the sensor 51 can be implemented in a part of the fiber thanks to its natural structure. For example, one end of the fiber line in direct contact with the surrounding environment can act as a sensor. The geometry of the fiber is known, the optical index can vary with temperature, and at the interface representing a

VIA * 31333Β1

20 SR 36626 DB ؛ fiber end (fiber optic interface / surrounding environment), a backscattered or reflected light will inform the temperature of the surrounding environment. This will also apply to other parts of the fiber line, and a temperature distributed along the fiber can be measured. Also, other parameters can be measured as a result.

Another type of sensors can be used. Many other physical parameters can be measured using miniaturized sensors which are self-powered. The associated electronics are small and have low consumption: a sensor with a limited volume and a limited power supply makes it possible to obtain a minimum volume. For example, the sensors can be of the MEMS type. The sensor can also be self-sufficient in terms of power supply, such as for example an optical sensor: there is no need for a conventional and expensive package including electronics, power supplies and analysis devices. For example, Bragg grating sensors can also be used for pressure measurement and Bragg grating sensors measuring both temperature and pressure can be made.

In another embodiment, multiple optical sensors can be arranged in a network or network configuration with individual sensors multiplexed using time division multiplexing or frequency division multiplexing, these sensors can be deployed. along the first fiber. Even when

VIA * 31333Β1 j SR 36626 DB 21 Bragg grating sensors are used, there is no need to use multiplexing; multiple Bragg grating sensors are arranged in a series grating each wavelength sensor and

Sensor deployment transmitter / receiver

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provide a measurement profile in the annulus.

Additionally, the array of sensors can increase the spatial resolution of temperature, pressure, stress, or flow data in the wellbore.

Preferably, the first device comprises an actuation system initiating the unwinding of the first line of optical fiber (not shown). The actuator can be, in one embodiment of Figure IA, an unlocking device unlocking the first coil when a plug (for example, the plug 20) is in contact with the support sleeve 8Α. Likewise, the actuator may be, in one embodiment of Fig. 1B, a rupture disc burst on the plug 21 (the plug has a hole and the first coil is placed therein). 25 unlocking the first coil when the cap 21 is in contact with the support sleeve 8Α. Preferably, the first device also comprises a distribution system facilitating the unwinding of the first line of optical fiber (not shown). The dispensing device may be a wheel which moves in rotation as the fluid flows through.

Α * 31333Β1 ا SR 36626 DB 22 through: the rotating action unwinds the first line of optical fiber and the fluid flow action ensures that the first line of optical fiber moves along substantially longitudinal lines of 1 annular space.

In other embodiments, the first device may consist of different coils (not shown) of the type of the first coil, placed uniformly around the back-up sleeve for the embodiment of Fig. 1A, in this manner. the coils could be unwound in the annulus at various locations and, if various sensors are used, a three-dimensional mapping of the annulus can be achieved.

In another aspect, the system described herein is used in a process for cementing a well and monitoring said cementation process. Figures 2Α to 2D show the steps of the method according to the invention. In a first step (Figure 2Α), when the cement 70 is ready to be distributed, a first plug 21 is released in the casing 2. The cement 70 is pumped behind the first plug, thereby moving the first plug to the bottom of the tube. hole with spacer fluid 90. While the first plug 21 moves in the descent hole, it comes to bear against a support sleeve 8Α of the casing shoe 8. The support sleeve comprises the first coil 41 and the exchange means 61, as described above, and the casing shoe is implemented as the first device. The hydraulic pressure from the cement above the first plug exerts

Α 31333Β1

j. SR 36626 DB 23 force until sufficient to cause a diaphragm rupture (pressure disc burst) in the first plug. Then, in Figure 2Β, the cement 70 flows through the first plug and the floating valve and back up into the annular space و between the formation 6 and the casing.

2. At this second step, the first coil 41 is allowed to unwind, advantageously thanks to an actuation system (not shown). The first line 10 of optical fiber 11 is then transported by elevation in the annulus 9 with the cement 70. Normally, the lifting forces are sufficient to allow proper deployment of the first fiber optic line 11 in the annulus 8, however, advantageously, a distribution system can be used to aid unwinding, for example a wheel. distribution box rotated by the flow of cement through it (not shown), also a tulip can be used at the end of the first fiber optic line (not shown).

In Figure 2C, the third step of the method is shown, in which the second device of the invention is deployed in the well. After a sufficient volume of cement has been placed in the wellbore, a second plug 20 is deployed in the casing 2. The second plug comprises a second coil 40 of the second optical fiber line 10 and exchange means. 61, as described above. As the second plug 20 moves through the downhole 30, the second line of optical fiber 10 is deployed in the tubing. At one end of the second

Via -31333Β1) SR 36626 DB 24 fiber, the second fiber is attached or fixed at a first position 4, or reference point. As will be appreciated, the second fiber is unwound from the second spool only by moving the second plug to a second position 4 ', which corresponds to a dynamic point. An upper part 10Α of the second fiber corresponds to the unwound fiber (between the first position and the second position) and a lower part 10Β of the second fiber corresponds to the wound fiber, still in the second coil. The dynamic point as a function of the reference point or the second position as a function of the first position informs the location of the plug in the well or the rate of movement of the plug in the well. The first position 4 is placed inside a cementing head 3, which is a static point. From this first position the second fiber is linked to a light emitting or receiving device 12. At the same time, the first fiber 11 is unwound from the first coil by the continuous flow of the cement 70. Advantageously, the first line of optical fiber 11 comprises multiple sensors 51Α, 51Β, 51C ... implemented in the second fiber. The sensors are Bragg grating type sensors. The sensors are distributed along the second fiber in such a way that when the line is deployed in the annulus the parameters can be monitored in said annulus at various depths and locations.

hA 3333Β1

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In figure 2D, the fourth step of the process is shown, at which the second plug 20 bears against the first plug 21. The first optical fiber line 11 is then correctly deployed in the annular space to a depth predetermined, or even, if necessary, up to the surface 7. In this configuration, a first device and a second device are in close proximity to allow the exchange means 61 to function correctly. In a first embodiment, the exchange means 61 will operate when contact between the first and second devices is effected, an interconnection of the two parts of the exchange means 61 being necessary. In a second embodiment, the exchange means are wireless and will operate when the two parts of the exchange means 61 are in close proximity. The exchange means can be self-supplied with light energy coming from the fiber. Advantageously, the electronics used in the exchange means will consume little or very little; in this case, a distance to transfer the information wirelessly may be limited. Preferably, however, the exchange means 61 operates when the two parts are separated by less than one meter, and more preferably less than 50 centimeters. Advantageously, the exchange means are an RF transmitter / receiver controlling a light source and a photoreceptor. Then the cement 70 is allowed to harden.

<img file="MA31333B1_D0004.tif" />

ΜΑ '31333Β1

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The sensors 51Α, 51Β, 51C measure information relating to parameters in the well. For example, as shown in Figure 2D, the sensors measure a temperature in the annular space informing of the hardening of the cement 70. The information is read from the surface 7, thanks to a light pulse: sent through the second fiber 10, transferred to the first fiber 11 by the exchange means 61, sent to a sensor and returned 10 by the same path to the surface (sent through the first fiber 11, transferred to the second fiber 10 by the exchange means 61 and finally sent by the second fiber 10 to the surface). In other embodiments, the first fiber optic line may reach surface 7, or it may be attached to a digital temmetry (DTS / Ρ) system / protocol box so as to have a. full closed loop instrumentation in cement 70. In another aspect, the second device is of the type disclosed in European Patent Application No. 06290801.7 by the same applicants, and a method for determining a depth, location and speed of the second plug can be used.

Using the above method, it is possible to confirm that the first and second plugs have both been deployed and have reached their correct operating positions. In addition, other information can be determined. First, the pressure and temperature in the pipe and thus the development over time of the depth of the plug.

VIA ٠31333Β1

I SR 36626 DB 27 are measures; thus confirming the launch and arrival of the caps, as well as the details of the passage along the tube (second cap only). Second, the pressure and temperature in the annulus and thus the instant at which the cement hardens in the annulus can also be determined. One of the major factors in downtime during the well construction process is the wait for cementing time. Being able to accurately determine the instant at which the cement has set could significantly reduce this time. The increase in consistency upon curing is accompanied by an increase in temperature resulting from the exothermic reaction which occurs when the cement hydrates. The change in temperature (or perhaps the rate of change in temperature at static hydrostatic pressure), could then be used to indicate that operation has occurred, that the cement has hardened, and that operations may. continue. Third, by continuous monitoring, it may also be possible to detect by distributed temperature variations or by attached acoustic sensors or by a direct density sensor, if there is an inlet of fluid from the reservoir to a microphone. - annular space. Indeed, it may be possible to independently corroborate (from a record of the adhesion of the cement) whether the cement has good adhesion or not.

Μα '31333Β1

SR 36626 DB 28

If the first fiber to be deployed in the annulus is likely to reach the surface, it can also be deployed using an additional bottom plug which is sucked along the casing during the circulation of slurry. This process would attach the fiber to a DTS / Ρ package so that temperature and pressure distribution in the annulus is achieved before starting the cementing spot itself.

The present invention has been described for plugs in the case of a cement stain, where it is important to define a location of the plug and / or information regarding the woc. Other applications of the device and of the method according to

The invention includes attaching the coiled fiber spools to any type of object being moved in the well, such as a puncture gun, a recoverable insert or any type of tool being moved in the well, such as for example a drilling tool, a recording tool, a recording tool while drilling, a measuring tool while drilling, a test tool; any type of tool suspended from a drill pipe, wire rope, coiled tubing.

Other applications of the device and method according to the invention include securing the first position to any one of a static or dynamic point, for example in submarine or downhole operations.