EP0364362B1 - Method and device for logging non-eruptive wells - Google Patents

Description

The present invention relates to a method and a device for logging production in inclined or horizontal wells.

The essential role that production logging could play in the strategy of operating a horizontal or strongly inclined oil well, if it could be carried out correctly, should be emphasized beforehand. Indeed, it is generally accepted that a horizontal well is likely to replace several vertical wells (generally two to four) and this both from the point of view of the production they can supply (increase in the production index ) and that of recovery (increase in drainage area and reduction in problems of formation of a water cone or "coning").

However, if this double advantage recognized in the horizontal well is valid in the case of a homogeneous reservoir, it may not be the same in the much more frequent case of heterogeneous reservoirs. Indeed, due to the presence of heterogeneities, the overall production of the well may become unprofitable because of an inflow of water which can be characterized by a "water-cut" ratio (Quantity of water / Quantity of liquid) or a gas / oil ratio, generally referred to in English as "Gas Oil Ratio" (GOR) too high. This production may have to be reduced, for example to limit the GOR to an acceptable value, even though this production problem may only come from a limited area of the drain. Even if this type of problem does not systematically condemn the use of horizontal wells on this type of deposit, it is clear that the horizontal well does not offer here all the flexibility that the producer could wish to optimize the exploitation of the field. In addition, it should be noted that the set of vertical wells which could be substituted for the horizontal well would offer more possibilities, the vertical well draining the part of the reservoir responsible for the production problem being able to be easily closed without harming the production of the other wells .

The way to get around this problem is obviously the use of selective completion in the horizontal drain, allowing either to modulate the production zone by zone, or to close the zone of the drain presenting a problem.

The use of selective completion can be designed at two different stages in the life of a well: either immediately after drilling the well, or later, when the need for its use appears.

• il convient tout d'abord de justifier a priori l'investissement supplémentaire que représente les équipements de complétion sélective.
  
• il faut ensuite définir les zones à individualiser à partir d'une description statique du réservoir.

In the first case, it is clear that the decision to use a selective completion is delicate and this for several reasons:

• it is first of all advisable to justify a priori the additional investment that represents selective completion equipment.
  
• it is then necessary to define the zones to be individualized from a static description of the tank.

The deferred decision has the advantage of being taken in full knowledge of the facts: the additional investment will be made only on the wells which require it and only when it becomes necessary. In most cases, it will not even be carried out until after the well's amortization period. We can, moreover, think that we can more easily define the zones to be isolated if we also have dynamic data on the reservoir, in particular through the use of production logs.

Intervention can on the other hand be made difficult, if not impossible, due to the provisional completion which will have been used during the first phase of exploitation of the well, for example by the use of a non-cemented perforated tube (generally called "pre liner" -perforated "by specialists).

On the other hand, this mode of production (1st non-selective phase, 2nd selective phase) can, in some cases, be the cause of a decrease in ultimate recovery.

The first solution (selectivity from the start of production) therefore seems more attractive on a technical level, but not necessarily on an economic level. The solution which consists of cementing and perforating a tube over the entire length of the drain, a solution which subsequently allows any possibility of selectivity, must be discarded for reasons of cost in certain cases.

The best solution therefore consists in carrying out the first phase of production in an open well (in English "open-hole"), but it is not always possible, due to the uncertainties as to the mechanical strength of the well.

As a result, the most frequently encountered scenario is that of non-cemented wells.

Whatever the completion adopted for the horizontal well, when a problem of production of undesirable fluids appears, it becomes important to be able, on the one hand, to locate the zone or zones possibly responsible for this production, on the other hand, to evaluate the potential of the well when these areas are closed.

Only production logs can provide the necessary answers. However, it turns out that their implementation comes up against difficulties due on the one hand to horizontality, on the other hand to the mode of completion.

Document FR 2 519 689 discloses an installation for testing and activation, but the effluent from upstream or downstream cannot be dissociated from the measurement means. In addition, this method is not suitable for inclined or horizontal wells.

Among all the possible modes of selective completion (total or partial cementing, training packers), or non-selective (open-hole, pre-perforated liner), the case of the perforated tube is that which combines all the difficulties. This is what will be considered later, the cases of production measurements within other completions can be obtained by introducing the corresponding simplifications.

The problems related to horizontal well production measurements result from a combination of interpretation difficulties already known in vertical wells and difficulties specific to horizontal wells mainly due to the mode of transport of the probes, the particular effect of gravity and the type of completion specific to this type of well (large liner diameter, often non-cemented liner, etc ...)

The present invention relates to the case where the well is non-eruptive and must be activated to produce.

The present invention can also be applied to vertical wells.

The essential purpose of a production log is to provide the flow profile of each phase along the drain. This result is obtained by carrying out and interpreting one or more measurements made in the well.

The main common measures are:
- "spinner" type measurement. Devices of this type provide the rotational speed of a propeller driven by the flow. The measurement therefore depends essentially on the flow speed of the fluid, but also on its viscosity.

The problems associated with this type of measurement arise essentially from the heterogeneity of the velocity field in a cross section of the well, from the stratified nature of the flow, from a possible difference in the flow velocities of each phase, from possible counter-current movements, for example with a flow in the opposite direction behind the tube (case of non-cemented completion) or, if a dispersed flow can be obtained, the need to know the composition of the fluid in each phase and the viscosity of the mixture .

Tools have been designed to at least partially solve some of these problems, in particular propeller flow meters: FBS (Full Bore Spinner), petal flow meters.

Even in the case of the petal flow meter, there remains the problem of the flow behind the tube (in the general flow direction, or against the current) and the problem of the calibration of the propeller response .
- measurement by radioactive tracer. This is a direct measurement of flow velocity. The problems mentioned above concerning the complexity of the flow of fluids remain valid. Mention should be made of the current development of tools using tracers preferentially soluble in oil and tracers preferentially soluble in water.
- density measurement. The principle of measurement that can be used in a horizontal well is an absorption of γ rays. These measurements generally encounter a problem of calibration, representativeness of the measurement (the measurement does not include the entire section of the flow) and the difference between the composition of the fluid in the well and that of the fluid in flow (water hold -up). With regard to this last point, it is worth pointing out a peculiarity of horizontal wells the problem of retention of the heavy phase, in particular of water (designated in English by "water hold-up") is encountered whenever gravity works in the opposite direction of the flow (vertical well, deviated α <90 °, α being the angle of inclination of the well on the vertical). On the other hand, in the case where gravity acts in the direction of flow (horizontal well α> 90 °) it is likely that we will encounter a phenomenon of retention of the light phase, such as gas.
- measurement of water content by measurement of the dielectric constant. The response of this type of tool requires calibration and very much depends on the nature of the flow (dispersion from one phase to the other).

For all these measurements, the presence of solid particles may also pose significant problems, among other things deterioration of the flowmeter propellers.

Other measures should be noted, such as pressure and temperature measurements.

According to the present invention, a casing is used, generally designated in English by "tubing" for lowering the measuring tools.

We then arrive at the design of a modular system of production measurements in horizontal wells whose composition is to be defined according to the well, its completion and the nature of the fluids produced. If the implementation of such a system is a priori heavier and more complex than that of a conventional production log, it should be noted that, on the one hand, such a conventional log cannot offer sufficient precision. and that, on the other hand, these measures will only intervene when a selective intervention (selective completion or selective treatment) becomes necessary and will in any case impose a disequipping of the well.

The implementation of a production log using tubings supposes to simplify the interpretation that the distribution of pressures in the drain is not too modified by the position of the casing train (tubing) in the drain , that is to say that the pressure drops in the annular between the casing and the perforated tube are negligible. This point can be checked during measurements for the use of a pressure sensor (s) evaluating the pressure drop in the ring finger.

According to the present invention, the well is activated to carry out the measurements. To do this, the casing can be fitted using a pump enabling the well to be activated. For reasons of simplification of implementation, the drive mode of the pump will then be either electric or hydraulic (turbopump or jet pump).

Thus the present invention relates to a method for performing production logs in a non-eruptive well having or not an inclined or horizontal part. This process includes the installation of at least one measurement means upstream of an activation means, eg a pump, the activation of the well to cause the production of effluents from both upstream and downstream sides with respect to said measuring means and the treatment by said measuring means of at least part of the effluent coming from the part of the well upstream of said measuring means.

It will be possible to treat by a second measuring means at least part of the flow coming from downstream relative to said first measuring means.

The first measurement means can deal substantially with the entire upstream flow.

The second measurement means will be able to process substantially all of the downstream flow.

It will be possible to check the pressure difference existing in the annular of the production well on either side of the first measuring means.

Likewise, conservation reports may be carried out, in particular debits from one or more phases.

The first measurement means can be calibrated by eliminating the downstream flow.

The present invention also relates to a device for carrying out production logs in a non-eruptive well, this device comprises activation means for activating the production of the well, at least one measuring means, this means being placed upstream of said means. activation, connection means comprising at least one opening between the activation means and said measuring means, the measuring means being adapted to treat at least part of the effluent coming from upstream of the measuring means.

The device may include a second measuring means which can treat at least part of the downstream flow, the inlet of this second measuring means being connected to said opening.

The device may also include means for separating the flow coming from upstream from the flow coming from downstream, relative to said first measuring means.

The device may include means for measuring pressures or pressure differences on either side of said first measuring means.

The device may include means for adjusting the pressure difference prevailing in the annulus of the well on either side of said first measuring means.

The pressure measurement means can measure this pressure difference and at least one of the upstream or downstream pressure prevailing in the annular of the well on either side of the first measurement means.

The activation means may include an electric motor or a hydraulic motor.

The activation means and the measurement means may be fixed to the end of a casing.

The activation means may include a hydraulic motor powered by a secondary casing placed in said casing.

The device and method according to the present invention apply to vertical, inclined or horizontal wells.

Information can be transmitted from the bottom of the well by electromagnetic waves, by mud wave or by electric cable.

The device according to the invention may include means for transmitting information by electromagnetic waves.

• les figures 1 et 2 représentent des modes de réalisation comportant une pompe d'activation électrique,
• la figure 3 illustre un mode de réalisation comportant une pompe d'activation hydraulique,
• la figure 4 montre la disposition des ensembles de mesure relativement au schéma d'écoulement des fluides,
• la figure 5 représente la position du tubage dans une position permettant le calage ou étalonnage d'éléments de mesures,
• la figure 6 représente un équipement pour la détection des venues de sable, et
• les figures 7 et 8 montrent des courbes relatives aux venues de sable et d'eau.

The present invention will be better understood and its advantages will become more clearly apparent from the following description of particular, non-limiting examples illustrated by the figures appended hereto in which:

• FIGS. 1 and 2 represent embodiments comprising an electric activation pump,
• FIG. 3 illustrates an embodiment comprising a hydraulic activation pump,
• FIG. 4 shows the arrangement of the measuring assemblies relative to the flow diagram of the fluids,
• FIG. 5 represents the position of the casing in a position allowing the calibration or calibration of measurement elements,
• FIG. 6 represents an equipment for detecting the coming of sand, and
• Figures 7 and 8 show curves relating to the inflow of sand and water.

In the examples given below, the sealing means are placed substantially at the same level as the first measuring means.

FIG. 1 represents a production well 1 in which it is desired to carry out measurements of characteristics of fluid flow linked to the formation along the part of the well in production, these measurements having to account for variation of certain characteristics between different points of the production area of the well 1. This well comprises a substantially vertical part not shown and a part 3, substantially horizontal or inclined relative to the vertical, in which oil production is carried out in normal operation.

This production zone comprises a tube 4 perforated over at least part of its length. It is through the perforations that the flow of fluid from the geological formation takes place during activation.

The present invention proposes to obtain information on these flows and this in a differentiated manner for several locations of the production part of the well.

Such information may be the flow rate, or the composition of the mixture produced. The present invention can in particular make it possible to know the flow rate as a function of the curvilinear abscissa along the production drain. Thus, for example, it is possible to determine the portions of the drain for which water is mainly produced and to intervene on these portions.

Reference 6 designates the casing of the well in the non-production area and reference 7 designates the shoe at the end of the casing.

According to the present invention, a casing 8 is lowered into the well comprising a means of activating the production comprising a pump 9 and measuring equipment 10.

For this solution it is recommended to use protectors or centralizers 11 in the deviated and horizontal part of the well.

The reference 12 designates the annular part between the tube 4 and the casing 8. It is in this zone that the protectors 11 are located.

The tube 4 can be cemented (as shown in Figure 1) or not (see Figure 2).

In the case of FIG. 1, the pump 9 is activated by an electric motor which is integrated into it. This motor is powered by an electric cable 14 located in the annular zone 12, as well as in the annular zone 13 located between the casing and the casing 6 over the entire length of the casing. This arrangement allows the electrical connection between the motor and the cable to be made on the surface. The electric cable 14 is unwound on the surface as the elements constituting the casing 8 are assembled. This assembly is accompanied by an increasing penetration of the motor-pump assembly into the well.

The casing 8 is sealed over its current length relative to the annular space 12. The fluid which enters the casing is that which has been treated by the pump 9.

The intermediate zone 15 of the casing situated between the pump 9 and the measuring equipment 10 has openings 16.

The measuring equipment 10 is traversed by the flow of fluids coming from upstream from the well, considering the direction of flow of the fluid coming from the upstream part 18 and going towards the inlet of the pump 9.

Thus the measuring equipment 10 can include a flow channel within it.

According to this embodiment when it is desired to carry out measurements such as flow measurements, the pump 9 is activated by supplying it with electricity by the cable 14.

Under these conditions, the well is activated and the pump delivers fluid from the downstream part 17 and the upstream part 18 considered in the direction of flow relative to the measuring means 10.

The fluid coming from the downstream part 17 reaches the pump through openings 16 and the fluid coming from the upstream part 18 passes through the measuring equipment 10. Due to the existence of the openings 16, the measuring equipment 10 appreciably treats only the fraction of the effluent coming from the upstream part of the production drain. Thus, a selective measurement is obtained. It then suffices to move the pump and measuring equipment assembly by adding or removing a certain number of elements from the casing to achieve a new measurement location and perform measurements.

The establishment of a balance sheet, in particular of flow, allows us to know the evolution of certain characteristics along the production drain. Thus, it is possible to know according to the curvilinear abscissa of the drain the local flow of the formation and its composition in water, gas, oil ...

FIG. 2 represents a variant of the embodiment of FIG. 1.

In FIG. 2, the motor and pump assembly is supplied with energy by a cable 19 which runs inside the casing 20 and is connected to the motor by a bottom connector 21.

The reference 22 designates a connector with side entry allowing the passage of the cable 19 in the annular space 23 of the well. This solution makes it possible to reduce and in certain cases to eliminate the routing of the cable in the annular space of the deviated or horizontal part of the well.

The establishment of the cable 19 and its connection to the bottom connector is done in a conventional manner.

In the case of an electric pumping, a transmission of the data, for example digital data obtained by the measuring equipment could be conceived using the power conductor (s) contained in the cables 9 or 19.

FIG. 3 represents an embodiment according to which the activation pump is driven by a hydraulic fluid motor, such as a so-called "sparrow" type hydraulic lobe motor.

According to this embodiment, a casing 24 is lowered into the well. This tubing has two parts. The first part 25 of the casing is separated from the second part of the casing 26 by a sealed element 27 such as a flange.

A secondary casing 28, possibly flexible and rollable of the "coiled tubing" type, connects the first part of the casing 25 to the hydraulic motor of the pump 9 through the second part 26 of the casing.

The annular space 29 between the second part 26 of the casing and the secondary casing communicates with the discharge orifices 30 of the pump 9. Furthermore, this annular space 29 communicates with the annular space 34 between the first part 25 of the casing and the casing by means of openings 31 made in the vicinity of the upper end of the second part 26 of the casing above the sealed element 27.

The reference 32 designates sealing means such as cups. These cups seal between the casing 33 and the casing 24.

Thus the annular space between the casing 33 and the casing 24 is divided into two.

The cups 32 are located below the openings 31. Thus the upper annular space 34 located between the casing 24 and the casing 33 communicates through the openings 31 with the annular space 29 located between the secondary casing 28 and the internal wall of the second part 26 of the casing 24.

The lower annular space 35 is delimited by the casing 33, the cups 32 and the external wall of the second part 26 of the casing 24.

The part located under the pump 9, that is to say the intermediate zone and the measuring equipment are substantially identical to those of Figures 1 and 2, moreover the common elements have the same references.

In this embodiment, the working fluid which feeds the hydraulic motor is transferred from the surface pumps 100 through the first part 25 of the casing 24, through the secondary casing, into the hydraulic motor which drives the pump 9 and is then discharged, at the same time as the fluid pumped from the drain, through the discharge orifices 30 towards the annular space 29, it passes through the openings 31 to join the upper annular space 34 and then join the surface where it can be treated by equipment 110. Of course, the sealed cups 32 prevent it from joining the lower annular space 35.

In the case of this type of pumping, the measurements made at the bottom of the well could be transmitted to the surface using pressure pulses in the circuit of the pump's working fluid (type MWD mud wave transmission).

Reliability of production measurements and calibration sensors could be increased by simultaneously carrying out identical measurements on the part of the flow coming upstream and on that coming downstream of the production drain relative to the direction of flow.

FIG. 4 represents an embodiment allowing in particular these measurements.

The reference 36 designates the geological formation, the reference 37 the tube comprising perforations, the reference 38 the sealing cups. These cups make it possible to isolate the upstream part well from the flow of the downstream part.

The reference 39 designates the measurement equipment which operates on the upstream flow, these means correspond substantially in their function to those shown in FIGS. 1, 2 and 3.

The reference 40 designates measuring equipment which operates on the downstream flow. The downstream flow comes to these devices 40 through the channel 41 which communicates with the annular space 420.

The channel 41 does not communicate with the upstream fluid having passed through the first measuring equipment 39 or upstream measuring equipment. The fluid coming from these upstream measuring equipment is mixed with the fluid coming from the downstream part of the drain only after this downstream fluid has passed through the downstream measuring equipment 40.

The pump 42 delivers all of the upstream and downstream fluid.

FIG. 4 shows a pump actuated by an electric motor powered by the cable 43.

The measurement equipment 39 and 40 can be connected by electrical wires not shown to an electronic unit 44 used to process these different signals to transfer them to the surface by the electrical cable 43 which may include one or more electrical connections.

The comparison of the bottom measurements with the measurements carried out at the wellhead brought back into bottom condition allows a verification of the measurements and their validation by the establishment of balances (conservation of the flows of each phase).

The presence of redundant measurements and simple conditions of continuity of the flows of each phase during moving the device in the well can allow direct calibration of the measurement set. Another possibility is to vary the total flow without moving the set of measurements.

Finally, there is a particularly advantageous possibility from the point of view of tool calibration, when this assembly shown in FIG. 4 is positioned at the head of the perforated tube, at a place where this tube is not yet perforated. (see figure 5).

In fact, in this case, the entire production from the well passes through the upstream measuring device, the cups 2 preventing the fluid from flowing according to another circuit. The zone 45A even if it is not cemented forms a dead end for the fluid. Calibration can be easily performed by comparison with wellhead measurements. Several measurement points can be obtained by varying the pump flow. If necessary, the downstream measuring device can be calibrated by imposing a circulation on the well head via the annular of the casing which can have a diameter of 24.5 cm (9.˝5 / 8).

It can be noted that this device also has the advantage on the one hand of a concentration of the flow allowing a dispersed flow and a greater precision of the measurement, on the other hand eliminates any risk of circulation against the current in the well (only the flow rates at the intake of the pump are counted).

In the case of a measurement inside a non-cemented perforated tube, an error can occur due to a circulation behind the tube (part of the downstream flow taken into account by the upstream flow meter or vice versa).

We can, at first, think of obtaining a qualitative indication of such circulation behind the perforated tube by having a differential pressure measurement between the inputs of the two upstream and downstream measuring devices.

This measurement actually provides the direction of leakage behind the liner, but cannot give any indication of the value of fluid flow. It can however be assumed that this leakage rate is proportional to this pressure difference Q _F = αΔp. It will therefore zero if the pressure drops in the two measuring devices are identical.

In FIG. 4, the references 45 and 46 designate absolute, relative or differential pressure sensors which are connected to the electronic unit by lines 47.

The use of a device making it possible to vary the pressure drops in one of the two sets of measurements or less makes it possible to minimize the error due to the leakage rate by adjusting the differential pressure to zero. Such a device can be adjusted by a command from the electronic unit 44 or can be autonomous.

• positionnement de l'ensemble dans le drain.
• débit de la pompe Q_T
• mesure des débits amont et aval et de la pression après avoir ajusté le dispositif mentionné ci-dessus pour régler la pression différentielle à une valeur nulle. $${\text{Q}}_{\text{T}}{\text{= Q}}_{\text{av}}{\text{+ Q}}_{\text{am}}$$
  
• fermeture complète du débitmètre aval. Cela suppose que les moyens de mesure aval 40 comportent un moyen d'obstruction télécommandé.
• ajustement du débit de la pompe de façon à obtenir la même pression dans la partie amont du drain. Nouveau débit Q′_T = Q′_am . Mesure de la pression différentielle Δ_P
• La caractéristique de la fuite est alors déterminée par $$\text{α′ =}\frac{\text{Q′am - Qam}}{\text{Δp}}$$
  

The characteristics of the leak behind the perforated tube could be assessed as follows:

• positioning of the assembly in the drain.
• pump flow Q _T
• measurement of the upstream and downstream flows and of the pressure after having adjusted the device mentioned above to adjust the differential pressure to a zero value. $${\text{Q}}_{\text{T}}{\text{= Q}}_{\text{av}}{\text{+ Q}}_{\text{am}}$$
  
• complete closure of the downstream flowmeter. This assumes that the downstream measurement means 40 comprise a remote-controlled obstruction means.
• adjustment of the pump flow so as to obtain the same pressure in the upstream part of the drain. New flow Q ′ _T = Q ′ _am . Differential pressure measurement Δ _P
• The characteristic of the leak is then determined by $$\text{α ′ =}\frac{\text{Q′am - Qam}}{\text{Δp}}$$
  

Furthermore, one can seek, by a throttling system of one of the two upstream or downstream circuits, to cause an artificial pressure drop in the measurement and determine the leak from the measurements, in particular of the pressures and flow rates upstream. and downstream.

The presence of solid particles (sand) in the production flow is likely to pose a problem with the measuring instruments, on the one hand, with the pump, on the other hand go. Furthermore, the determination of possible areas for the production of sand of limited extension could be advantageous insofar as it would allow the use of a process for controlling sand over a limited length of sand (possibility of using a chemical consolidation process, limited strainer length resulting in a lower cost and less risk of clogging).

Putting down a strainer measurement tool downstream would protect the measuring instruments.

The detection of sand production could be obtained using an impact detector 48 ("Noise Log") proposed by most of the logging companies.

A sand trap 49 interposed between the strainer 50 and the impact detector makes it possible, on the one hand, to obtain a sand sampling, on the other hand, to provide a semi quantitative indication on the measurements obtained by the detector d impact, by comparing the quantity of sand to the sum of the impact count recorded.

In FIG. 6, the sand trap consists in particular of a sand circulation circuit having a baffle shape upstream of the strainer 50.

FIGS. 7 and 8 show an example of the conclusions which the device and the method according to the present invention make it possible to obtain.

In these figures 7 the abscissa x represents the curvilinear abscissa along the production part of the drain. The ordinate of FIG. 7 represents the counts c carried out by the impact detector. Curve 51 represents the number of impacts (as a function of the curvilinear abscissa x. Between X1 and X2 this number is high. The integral of this curve is related substantially to the total amount of sand drained and can therefore be compared to the amount of sand collected in the sand trap 49.

FIG. 8, the abscissa axis of which is calibrated on that of FIG. 7, represents on the ordinate a quantity Q proportional to the quantity of water collected. This quantity can be for example the water-cut ratio which corresponds to the quantity of water produced compared to the total quantity of liquid produced (water + oil). More simply, this quantity can be equal to the flow of water produced.

In Figure 8 this quantity Q indicates a strong increase between x1 and x2 which corresponds to the area where there is a significant influx of sand.

Thus with these results, the production operator can decide to stop the production of the drain on the portion between x1 and x2 and thus increase the quality of the production of his well.

Two modes of information transmission from the bottom of the well have so far been described, one being transmission by electric cable and the other by mud wave.

It will not depart from the scope of the present invention to use an electromagnetic wave transmission as described in the article by MM. P. de GAUQUE and R. GRUDZINSKI entitled "Propagation of Electromagnetic Waves along a Drillstring of Finite conductivity" published in the review SPE Drilling Engineering from June 1987. Similarly, we will not depart from the scope of the present invention by combining some of these different means of transmission.

Claims (19)

1. Method for carrying out production well-logs in a non-flowing well having an inclined or horizontal section, including the positioning of at least one measurement means upstream of an activation means, e.g. a pump, activation of the well to initiate the production of effluent from the two sides upstream and downstream of the measuring means and the processing by the measuring means of at least part of the flow from the section of the well upstream of the measuring means.

2. Method in accordance with claim 1, characterised in that at least a part of the flow downstream of the first measuring means is processed by a second measuring means.

3. Method in accordance with claim 1, characterised in that this first measuring means processes essentially all of the upstream flow.

4. Method in accordance with claim 2, characterised in that the second measuring means processes essentially all of the downstream flow.

5. Method in accordance with one of claims 1 to 4, characterised in that the difference in pressure prevailing on either side of the first measuring means in the production well is monitored.

6. Method in accordance with one of claims 1 to 5, characterised in that patterns of continuity are calculated.

7. Method in accordance with one of claims 1 to 6, characterised in that the first measuring means is calibrated by eliminating the downstream flow.

8. Method in accordance with one of claims 1 to 7, characterised in that data is transmitted from the bottom of the well by electromagnetic waves.

9. Device for producing well logs in a non-flowing well, characterised in that it comprises activation means (9, 42) to initiate production of the well, at least one measuring means (10, 39), this means being located upstream of the activation means, connection means (15) having at least one opening (16, 41) between the activation means (9, 42) and the aforementioned measuring means (10), wherein the measuring means is adapted to process at least a part of the flow from upstream of the measuring means (10).

10. Device in accordance with claim 9, characterised in that it comprises a second measuring means which processes at least a part of the downstream flow, the inlet to this second measuring means being linked to the opening (16, 41).

11. Device in accordance with one of claims 9 to 10, characterised in that it comprises means for separating the flow from upstream and the flow from downstream of the first measuring means.

12. Device in accordance with one of claims 9 to 11, characterised in that it comprises means for measuring pressure levels or differences in pressure on either side of the first measuring means.

13. Device in accordance with one of claims 9 to 12, characterised in that it comprises means for regulating the pressure differential prevailing on either side of the first measuring means.

14. Device in accordance with claim 12, characterised in that the means for measuring pressure measures the pressure differential and at least one of the pressure levels upstream or downstream prevailing on one side or the other of the first measuring means.

15. Device in accordance with one of claims 9 to 14, characterised in that the activation means has an electric motor.

16. Device in accordance with one of claims 9 to 14, characterised in that the activation means has a hydraulic motor.

17. Device in accordance with one of claims 9 to 16, characterised in that the activation means and the measuring means are attached to the end of a tubing.

18. Device in accordance with claim 17, characterised in that the activation means has a hydraulic motor supplied by a secondary tubing located inside the afore-mentioned tubing.

19. Device in accordance with one of claims 9 to 18, characterised in that it comprises means for transmitting data by electromagnetic waves.

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