WATER / OIL EMULSION SENSOR AND DOWNHILL TOOL INCLUDING SUCH SENSORS.

Abstract

WATER / OIL EMULSION SENSOR AND DOWNHOLE TOOL INCLUDING SUCH SENSORS. A water / oil emulsion sensor (40) is sensitive to the water and oil content of a multiphase fluid mixture (MF) flowing as an emulsion in a hydrocarbon well (2).The sensor comprises a conductive tip (41) at a front portion, a hollow insulating body (42) at a middle portion and a hollow conductive body (43) at a rear portion, said front portion having a conical shape, said middle and rear portions having a substantially cylindrical shape, said portions of said sensor being coaxial, extending along a longitudinal axis (LL') and being assembled in a sealed manner, an inductive module (44) housed in the hollow insulating body (42) and comprising a transmitting coil (45) and a detecting coil (46), a capacitive module (47) housed in the hollow insulating body and comprising a cylindrical conductive surface (48), and an electronic unit (49) comprising a processing module (50) coupled to an inductive power supply and measurement module (51) connected to the inductive module (44), and to a capacitive power supply and measurement module (52) connected to the capacitive module (47).Figure for the abbreviation: Figure 1.

Description

Title of the invention: WATER / OIL EMULSION SENSOR AND DOWNHILL TOOL COMPRISING SUCH SENSORS. technical field

[0001] The invention relates to a water / oil emulsion sensor sensitive to the water and oil content of a multiphase fluid mixture flowing in a hydrocarbon well. In an emulsion, one liquid (the dispersed phase) is dispersed in another liquid (the continuous phase). In a multiphase fluid mixture flowing in a hydrocarbon well, there may be different types of emulsions. In particular, oil and water may form an oil-in-water emulsion (i.e., oil is the dispersed phase and water is the continuous phase) or a water-in-oil emulsion (i.e., water is the dispersed phase and oil is the continuous phase). A downhole tool, for example a production logging tool, including at least one water / oil emulsion sensor, is used to analyze the multiphase fluid mixture flowing from a hydrocarbon-containing zone in the hydrocarbon well.Such a downhole tool is particularly suited for deployment in hydrocarbon wells comprising vertical well sections, inclined well sections, substantially horizontal well sections, or a combination thereof. Such downhole tools typically operate in the harsh downhole environment of hydrocarbon wells under conditions of downhole pressure (usually in the range of 100 to 2000 bar) and downhole temperature (usually in the range of 50 to 200 °C), and in potentially corrosive fluids. Previous technique

[0002] During hydrocarbon well production, it is necessary to monitor various characteristic parameters, such as the relative volumetric flow rates of the different phases (e.g., oil, gas, and water) of the multiphase fluid mixture flowing down the wellbore from hydrocarbon-containing zones. Furthermore, current hydrocarbon wells often include a vertical well section, inclined well sections, steeply inclined well sections, and even substantially horizontal well sections. Interpreting the flow in such complex wells is difficult because small changes in well inclination and flow regime influence the flow profile. Thus, accurate monitoring requires sensors or probes capable of imaging a surface or a volume section of the duct and provide an estimate of the surface area or volume section occupied by each phase.

[0003] Hydrocarbon well production logging (e.g., oil and gas wells) presents many challenges related to the complexity of multiphase flow conditions and the harshness of the downhole environment.

[0004] Gas G, oil O, water W, and O&W mixtures circulating in wells, whether open-hole or cased wells, can flow as an emulsion depending on the relative proportions of the phases (known in English as "holdup"), their velocities, densities, viscosities, as well as the dimensions of the conduits and the well inclinations. In order to achieve a good understanding of the flow rates of the individual phases and to determine the relative contributions of each zone along the well, an accurate mapping of the types and velocities of the fluids is necessary over the entire cross-section of the well (open-hole portion) or conduit (cased portion) at different depths (i.e.The measured depth, defined based on the distance traveled by the logging equipment along the well from its location to the surface, differs from the actual vertical depth and is generally greater than the actual vertical depth due to well inclinations relative to the vertical. Furthermore, production issues vary considerably depending on reservoir types and well characteristics, necessitating flexible production logging technology that operates with different types of sensing physics. For example, in multiphase fluid mixtures flowing in hydrocarbon wells, oil and water often flow as an oil-water emulsion—that is, a dispersed liquid phase within a continuous liquid phase. Various types of oil-water emulsion can exist.For example, oil can be the dispersed phase, and water can be the continuous phase, with oil and water forming an oil-in-water emulsion. As another example, water can be the dispersed phase and oil the continuous phase, or it can be a water-in-oil emulsion. An emulsion is a pseudo-homogeneous fluid. Typically, the dispersed phase can be approximated by a spherical structure much smaller than a millimeter, for example, on the order of a micron, and therefore cannot be measured by conventional sensors such as local electrical sensors or even optical sensors. There is a need for a sensor that can measure emulsions regardless of the nature of the continuous phase (being oil or water) and the dispersed phase (being water or oil).

[0005] Furthermore, the high pressure, up to 2000 bars, the high temperature, up to 200°C, the corrosive fluids (H2S, CO2) impose constraints on the sensors and on the mechanics of the tools.

[0006] Furthermore, the presence of solids in the flows can damage the equipment. In particular, sand carried from reservoir rocks will erode the parts facing the fluid flow. Solids precipitated from the fluids produced due to changes in pressure and temperature, such as asphaltenes, paraffins, or scale, create deposits that contaminate the sensors and / or block moving parts (e.g., turbine flow meters).

[0007] Furthermore, deploying the tool in the well can be difficult and risky. In steeply inclined or horizontal wells, the tools must be pushed along the conduit using coiled tubing or pulled with a tractor, which is difficult when the tools are long and heavy. Conduits can be damaged by corrosion or stresses in the rock, which can create restrictions and other obstacles. During logging operations, the equipment can be subjected to significant shocks. Thus, in such environments, it is highly preferable to have lightweight and compact tools.

[0008] In addition, cost is also an important parameter in order to provide an economically viable solution for well performance evaluation, even in mature oil fields with low-producing wells that are being depleted with critical water production problems. Summary of the invention

[0009] The invention aims to provide a water / oil emulsion sensor for measuring multiphase fluid mixtures flowing as emulsions in hydrocarbon wells, regardless of the nature of the continuous phase (oil or water) and the dispersed phase (water or oil). Another objective is to design a water / oil emulsion sensor that is compact, accurate, and reliable. A further objective is to integrate at least one of these water / oil emulsion sensors into a downhole tool, for example, a production logging tool, that is structurally simple and reliable for operation under all downhole conditions.

[0010] According to a first aspect, a water / oil emulsion sensor is proposed that is sensitive to the water and oil content of a multiphase fluid mixture flowing as an emulsion in a hydrocarbon well, the water / oil emulsion sensor comprising: - a conductive tip at the front part, a hollow insulating body at the middle part and a hollow conductive body at the rear part, said front part having a conical shape, said middle and rear parts having a substantially cylindrical shape, said parts of said sensor being coaxial, extending along a longitudinal axis and being assembled in a sealed manner, - an inductive module housed within the hollow insulating body and comprising a transmitting coil and a detecting coil, - a capacitive module housed within the hollow insulating body and comprising a conductive cylindrical surface, and - an electronic unit comprising a processing module coupled to an inductive power supply and measurement module connected to the inductive module, and to a capacitive power supply and measurement module connected to the capacitive module, - The inductive power supply and measurement module is arranged to inject an inductive excitation current into the transmitting coil such that, if the multiphase fluid mixture is conductive, a first induced inductive current is generated in a first investigation zone surrounding the inductive module, and a second induced inductive current, proportional to the first induced inductive current, is measured in the detection coil. The second induced inductive current is representative of the water content within the multiphase fluid mixture in the first investigation zone. - The capacitive power supply and measurement module is arranged to apply a capacitive excitation voltage to the conductive cylindrical surface and to measure the capacitance of the multiphase fluid mixture in a second investigation zone surrounding the conductive cylindrical surface.the capacity being representative of the oil content within the multiphase fluid mixture in the second investigation area, - The inductive module is arranged in a nested and close position relative to the capacitive module inside the hollow insulating body at the mid-section, the transmitting coil and the detecting coil being in line and extending along the longitudinal axis, the cylindrical conductive surface being coaxial with the longitudinal axis, concentric, and surrounding both the transmitting and detecting coils such that the first and second investigation zones substantially overlap so that the water and oil content of the multiphase fluid mixture flowing as an emulsion can be determined at substantially the same location.

[0011] The conductive tip and the hollow conductive body may be made of a metallic alloy resistant to well conditions, and the insulating hollow body may be made of ceramic.

[0012] Each of said transmitting coils and detecting coils may comprise a core consisting of a hollow ferrite cylinder or a torus (square torus or circular torus), and a winding comprising several turns of a metal wire. The winding may comprise from a few turns (for example, eight) up to a few dozen turns (for example, thirty) of said metal wire.

[0013] The inductive power supply and measurement module can be arranged to inject an inductive excitation current having an amplitude ranging from 0.1 mA to 20 mA and a The frequency in the transmitting coil ranges from a few kHz (e.g., 1 kHz) to several hundred kHz (e.g., 900 kHz). As examples, the inductive excitation current can be a sinusoidal, square, or triangular periodic signal.

[0014] The capacitive power supply and measurement module can be arranged to apply a capacitive excitation voltage having an amplitude from 100mV to 9V and a frequency from 1kHz to 900kHz to the cylindrical conductive surface.

[0015] The cylindrical conductive surface can be supported on a support tube, said cylindrical conductive surface being made of metal, said support tube being made of a plastic or ceramic material.

[0016] The conductive tip can be connected to a ground potential by means of a tip wire, the tip wire closing a loop between the conductive tip and the hollow conductive body.

[0017] The water / oil emulsion sensor may further include a connector positioned at the rear of said sensor so as to close the hollow conductive body at one side of the sensor opposite the conductive tip.

[0018] The processing module can be arranged to extract complex impedance values ​​in angular phase and quadrature from complex inductance values ​​provided by the inductive power supply and measurement module connected to the inductive module combined with complex capacitance values ​​provided by the capacitive power supply and measurement module connected to the capacitive module and estimate the water and oil content on the basis of an experimental model fitted, for example, by a polynomial approximation (e.g., a polynomial of order n).

[0019] The water / oil emulsion sensor may further include an active counter electrode having a first part and a second part on each side of the conductive cylindrical surface, each of said parts being a ring having essentially the same diameter as the conductive cylindrical surface, the two parts being connected to a reverse voltage supply supplying the active counter electrode with a reverse voltage compared to a capacitive excitation voltage applied to the conductive cylindrical surface by the capacitive power supply and measurement module.

[0020] According to another aspect, a downhole tool is proposed comprising an elongated cylindrical body with a longitudinal axis, said body carrying a centering arrangement comprising articulated centering arms, said arms being able to be actuated from a retracted configuration to a radially extended configuration, in which at least one arm carries at least one water / oil emulsion sensor according to the invention.

[0021] Alternatively, the downhole tool may comprise an elongated cylindrical body with a longitudinal axis, the body comprising at least one groove opening partially externally to house at least one water / oil emulsion sensor according to the invention.

[0022] Several water / oil emulsion sensors can be connected to a main processing module so as to form a sensor network.

[0023] The downhole tool may further include another probe for analyzing the properties of the downhole fluid of any type, chosen from the group including sensors sensitive to physical parameters such as pressure, temperature, density, viscosity, refractive index, fluid velocity, number of bubbles and gas retention, fluorescence, spectroscopic absorption of the multiphase fluid mixture.

[0024] The water / oil emulsion sensor is characterized by a simple and compact structure offering high accuracy, low cost, and ease of use and maintenance. Each local sensor allows for the simultaneous measurement, within a well-defined measurement area of ​​small size (i.e., essentially in the same location), of the multiphase fluid mixture flowing as an emulsion in the hydrocarbon well, and thus, the water and oil content of the multiphase fluid mixture flowing in the hydrocarbon well with very good resolution. The downhole tool of the invention allows for the deployment of a single local water / oil emulsion sensor or an array of local water / oil emulsion sensors regardless of the well section orientation. Brief description of the drawings

[0025] The present invention is illustrated by way of example and is not limited to the accompanying drawings, in which similar references indicate similar elements: Figure [Fig.1] is a partial cross-sectional side view illustrating a downhole tool comprising a water / oil emulsion sensor of the invention in a horizontal well section in a fully deployed configuration; Figure [Fig.2] is a partial cross-sectional side view illustrating a downhole tool comprising a water / oil emulsion sensor of the invention in a vertical well section; Figure [Fig.3] is a partial cross-sectional side view illustrating a water / oil emulsion sensor of the invention according to a first embodiment and a corresponding operating principle; Figure [Fig.4] is a partial cross-sectional side view illustrating a water / oil emulsion sensor of the invention according to a second embodiment and a corresponding operating principle; Figures [Fig.5], [Fig.6], [Fig.7] and [Fig.8] are, respectively, a partial lateral sectional view, a side sectional perspective view, an exploded perspective view and an assembled perspective view illustrating the practical implementation of the water / oil emulsion sensor according to the second embodiment; Figures [Fig.9] and [Fig.10] are diagrams illustrating the response of the water / oil emulsion sensor of the invention in water / oil emulsions used to infer the water content and oil content of a multiphase fluid mixture flowing in a hydrocarbon well; Figures [Fig.11], [Fig.12] and [Fig.13] are, respectively, a side perspective view, a lateral cross-sectional view and a front view illustrating various embodiments of a downhole tool comprising a water / oil emulsion sensor array of the invention; and Figure [Fig. 14] is a perspective view from one side illustrating another embodiment of a downhole tool comprising several water / oil emulsion sensors of the invention. Detailed description

[0026] Figures [Fig. 1] and [Fig. 2] illustrate a downhole tool 1, for example a production logging tool, deployed in a wellbore of a hydrocarbon well 2 that has been drilled into an underground formation 3. In the particular example of Figure [Fig. 1], the downhole tool is deployed in a horizontal section of a hydrocarbon well. In the particular example of Figure [Fig. 2], the downhole tool is deployed in a vertical section of a hydrocarbon well. In both examples, said sections have been further fractured at defined locations (i.e., fracture groups). The downhole tool 1 is used to analyze at least one property of a multiphase fluid mixture MF flowing in the hydrocarbon well 2. The multiphase fluid mixture MF is characterized by retention, slip velocity, and phase segregation.Retention (from the English "hold-up") is the volume percentage of the gas, oil, and / or water content in the wellbore, measured over a cross-section (based on the wellbore's inside diameter, ID). Slip velocity is the relative velocity between the light and heavy phases. Phase segregation is the tendency of fluids to stratify into different layers due to density differences between oil (O), water (W), and gas (G), and due to the immiscibility of water and oil, and the limited miscibility (dependent on temperature and pressure) of gas in oil and water. Furthermore, oil and water can also flow as an oil-water emulsion, in which a dispersed liquid phase, DP (oil or water), is dispersed within a continuous liquid phase, CP (water or oil). Various types of oil-water emulsions exist.As a first example, oil and water can form an oil-in-water emulsion (oil being the dispersed phase and water being the continuous phase). As a second example, oil and water can form a... Water-in-oil emulsion (water being the dispersed phase and oil being the continuous phase). The wellbore refers to the drilled hole or borehole, including the open hole or uncased portion of the well. The borehole refers to the inside diameter of the wellbore wall, the rock wall delimiting the drilled hole. The open hole refers to the uncased portion of a well. Although most completions are cased, some are open, particularly in horizontal or steeply inclined wells where it may not be possible to effectively cement casings. The downhole tool 1 can be deployed and moved within the borehole of the hydrocarbon well 2 to perform various analyses of the MF properties of the multiphase fluid mixture, regardless of whether the hydrocarbon well is cased or uncased.The downhole tool 1 may include various subsections with different functionalities and may be coupled to surface equipment via a cable 5 (or alternatively, coiled tubing, a technique known as "coiled tubing," suitable for moving the tool in horizontal and steeply inclined wells). This cable can be implemented on surface equipment to move the tool along the well. At least one subsection includes a measuring device that generates measurement logs, namely measurements as a function of depth measured along the well or time, or both, of one or more physical quantities in or around the well 2. The cable logs are taken down the well, transmitted via the cable 5 to the surface and recorded there, or recorded down the well and retrieved later when a logging instrument is brought to the surface.Numerous logging measurements (e.g., electrical properties, including conductivity at different frequencies, acoustic properties, active and passive nuclear measurements, wellbore dimensional measurements, formation fluid sampling, formation pressure measurements, flow rate measurements, etc.) are possible during the movement of the production logging tool 1 along and within the hydrocarbon well 2 drilled into the subsurface formation 3. Auxiliary surface equipment is neither illustrated nor described in detail here. In what follows, the wellbore wall, regardless of whether it is cased (cemented or cased) or uncased, is referred to as the wall 6. Various fluid inflows (which may include solid particles) Fl, F2 can occur from the subsurface formation 3 into the wellbore 2.Once in well 2, these fluid inlets form the MF multiphase fluid mixture which typically flows towards the surface.

[0027] Figure [Fig. 3] is a partial cross-sectional side view illustrating a water / oil emulsion sensor 40 of the invention according to a first embodiment. Figure [Fig. 3] shows the water / oil emulsion sensor 40 inserted into a mixture of multiphase fluids MF in which the dispersed liquid phase DP (whether petroleum or water) is dispersed in the continuous liquid phase CP (whether water or petroleum).

[0028] Figures [Fig.5], [Fig.6], [Fig.7] and [Fig.8] are, respectively, a partial lateral sectional view, a side sectional perspective view, an exploded perspective view and an assembled perspective view illustrating the practical implementation of the water / oil emulsion sensor 40.

[0029] The water / oil emulsion sensor 40 comprises a conductive tip 41, a hollow insulating body 42, a hollow conductive body 43, an inductive module 44, a capacitive module 47, and an electronic unit 49. The conductive tip 41 is positioned at a front portion of the sensor. The hollow insulating body 42 is positioned at a middle portion of the sensor. The hollow conductive body 43 is positioned at a rear portion of the sensor. The front portion may be conical and is positioned at a distal area of ​​the sensor, which may help to avoid, or at least reduce, turbulence in the flow. The middle and rear portions are substantially cylindrical. All these parts are coaxial, extend along a longitudinal axis, and are assembled in a sealed manner.

[0030] The conductive tip 41 and the hollow conductive body 43 are made of a metallic alloy resistant to well conditions, for example, a nickel-chromium superalloy (e.g., "Inconel 718," a trademark of Special Metals Corporation). The hollow insulating body 42 is made of ceramic. The diameter dimensions of all these components are on the order of millimeters to suit the structure of the emulsion in which the dispersed phase can be approximated by spheres, each sphere having a size well below 1 millimeter, typically ranging from a few micrometers to a hundred micrometers. The length dimensions of all these components are on the order of centimeters.

[0031] The inductive module 44 is housed in the hollow insulating body 42. The inductive module 44 comprises a transmitting coil 45 and a detecting coil 46.

[0032] By way of example, each coil may comprise a core consisting of a hollow ferrite cylinder or a torus (square or circular), and a winding comprising several turns of a metal wire (for example, from eight to twenty turns). The two ends of the wire serve to inject an inductive excitation current into the transmitting coil 45 and to measure an induced inductive current in the detecting coil 46. The inductive excitation current may be a sinusoidal, triangular, or square (periodic) alternating current. The inductive excitation current may be characterized by an inductive excitation current frequency ranging, for example, from 1 kHz to 900 kHz. The inductive excitation current may be a low-power current, for example, having an amplitude on the order of milliamperes, for example, from 0.1 mA to 20 mA. The characteristic amplitude, frequency and phase of the inductive excitation current can be adapted to the characteristic parameters of the inductive module 44, for example, the size of the coil, the number of turns of wire, the type of material used for the core.

[0033] The capacitive module 47 is housed within the hollow insulating body 42. The capacitive module 47 comprises a conductive cylindrical surface 48. The conductive cylindrical surface 48 can be supported on a support tube 48A (see Figure [Fig. 5]). The conductive cylindrical surface 48 is made of metal, while the support tube 48A can be made of plastic or ceramic. The conductive cylindrical surface 48 is subjected to a capacitive excitation voltage. The impedance of the capacitive module 47 is determined to deduce the capacitance between the conductive cylindrical surface 48 and another conductive element representative of a ground potential GD, the gap of which is filled by the fluid medium to be measured. The capacitive excitation voltage can be a sinusoidal, triangular, or square wave alternating (periodic) voltage.The capacitive excitation voltage can be characterized by a capacitive excitation voltage frequency ranging, for example, from 1 kHz to 900 kHz. The capacitive excitation voltage can have, for example, an amplitude of a few hundred millivolts to a few volts, for example, from 100 mV to 9 V. The characteristic amplitude, frequency, and phase of the capacitive excitation voltage can be adapted to the characteristic parameters of the capacitive module 47, for example, the size of the cylindrical conductive surface 48 in terms of length, diameter, surface area, and type of material.

[0034] The inductive excitation current and the capacitive excitation voltage are independent of each other. This means that the characteristic amplitude, frequency, and phase of these currents and voltages, respectively, are optimized separately for the inductive module 44 and the capacitive module 47. Nevertheless, in a particular embodiment, the two circuits may be substantially identical.

[0035] The conductive tip 41 is connected to ground GD by means of a tip wire 57. The tip wire 57 passes through the hollow insulating body 42 and can be coupled to the hollow conducting body 43, for example via the electronic unit 49. The tip wire 57 closes the loop between the conductive tip 41 and the conducting body 43.

[0036] The electronic unit 49 is housed in the hollow conductive body 43. The electronic unit 49 comprises a processing module 50 (see Figures [Fig. 3] and [Fig. 4]), an inductive power supply and measurement module 51 connected to the inductive module 44, and a capacitive power supply and measurement module 52 connected to the capacitive module 47. The inductive power supply and measurement module 51 provides electrical energy, namely an inductive excitation current to the transmitting coil 45, and measures the induced inductive current supplied by the sensing coil 46. It may further include Features such as voltage regulation, current limiting, and overcurrent protection are included. The capacitive power supply and measurement module 52 provides electrical energy, namely a capacitive excitation voltage, to the conductive cylindrical surface 48 and measures the capacitance between the conductive cylindrical surface 48 and another conductive element representative of a ground potential GD. This other conductive element can be, as described in more detail below, a component of the downhole tool, sensor, or casing located close to the conductive cylindrical surface 48, for example, from a few millimeters to a few centimeters. Each of the inductive power supply and measurement module 51 and the capacitive power supply and measurement module 52 includes a driver amplifier for the analog section to drive the coils or capacitor and amplify the measured return signal.They may also include features such as voltage regulation, current limiting, and overcurrent protection. The processing module 50 processes the measured data and performs the necessary calculations to deduce the water and oil content of the multiphase fluid (MF) mixture circulating as a water / oil emulsion. It may include an A / D converter microcontroller and a microprocessor for data processing and analysis. Inductive and capacitive measurements are complex impedance measurements. The processing module 50 extracts complex impedance values ​​Z in phase and quadrature as explained below. The electronic unit 49 may further include a communication interface U0. The communication interface FO has communication capabilities to interact with the main processing module 59 of the downhole tool 1 (visible in Figures [Fig. 1] and [Fig. 2]).

[0037] The water / oil emulsion sensor 40 further includes a connector 56. The connector 56 is positioned at the rear of the sensor 40 and closes the hollow conductive body 43 on the side of the sensor opposite the conductive tip 4L. An electrical cable (not shown) which may include power wires and communication wires connected to the I / O communication interface is coupled to the connector 56. The electrical cable couples the sensor 40 to the main processing module 59 of the downhole tool 1 (see Figures [Fig.1] and [Fig.2]).

[0038] The inductive module 44 operates as follows. The inductive power supply and measurement module 51 is arranged to inject an excitation inductive current i1 into the transmitting coil 45 and to measure an induced inductive current i3 in the sensing coil 46. The excitation inductive current is a periodic current. When the multiphase fluid mixture MF is conductive (e.g., mainly water or water as the DC phase), a first induced inductive current i2 is generated in a first investigation zone IZ1 surrounding the inductive module. 44 outside the hollow insulating body 42, and a second induced inductive current i3 proportional to the first induced inductive current i2 is measured in the detection coil 46. The second induced inductive current i3 is representative of the water content within the multiphase fluid mixture MF in the first investigation zone IZL. When the multiphase fluid mixture MF is insulating (e.g. mainly oil or gas as continuous phase), the induced inductive currents i2 and i3 are harmed. The processing module 50 and the inductive power supply and measurement module 51 connected to the inductive module 44 determine the complex impedance of the inductance Zind=jLcol (where j is the symbol indicating the imaginary part; L is the inductance of the sensing coil; and col is the angular frequency related to the frequency fl of the inductive current, col=2irfl) by measuring the amplitude and phase (i.e. the angular component) of the second induced inductive current i3.In practice, the processing module 50 together with the inductive power supply and measurement module 51 connected to the inductive module 44 measure the induced current in the secondary coil (i.e. the sensing coil 46), which depends on the volume conductivity of the fluid surrounding the sensor, which depends on the volume fractions of water in the emulsion.

[0039] The capacitive module 47 operates as follows. The capacitive power supply and measurement module 52 is arranged to apply a capacitive excitation voltage vl to the conducting cylindrical surface 48 and to measure the capacitance of the capacitor composed of electrode 48 and the ground electrode GD, the gap between which represents a second investigation zone IZ2 filled with the polyphase fluid mixture MF. The capacitance is representative of the oil content within the polyphase fluid mixture MF in the second investigation zone IZ2. The capacitive excitation voltage vl can be sinusoidal, triangular, or square wave. More precisely, the capacitance is measured between the conducting cylindrical surface 48 and a nearby conducting element GD. When the polyphase fluid mixture MF is insulating (e.g.(primarily oil or oil as the continuous phase), the dielectric permittivity of the polyphase fluid mixture MF present between the cylindrical conductive surface 48 and the nearby conductive element GD is related to the oil content of the polyphase fluid mixture MF. The amount of water dispersed in the second investigation zone IZ2 will modify this permittivity, and therefore the associated capacitance (i.e., the water content modifies the thickness of the effective gap of the capacitor, and thus the measured capacitance value will depend on the water content of the water emulsion in the oil). When the polyphase fluid mixture MF is conductive (e.g., primarily water or water as the continuous phase), the capacitance is short-circuited, and no further measurements are possible with the capacitive method; therefore, the inductive method takes over for the other range. values. The nearby conducting element GD can be a conducting element of the sensor itself, or a conducting part of the downhole tool to which the sensor is attached (e.g., a body section, an arm, etc.). The processing module 50, together with the capacitive power supply and measurement module 52 connected to the capacitive module 47, determines the complex impedance of the capacitor Zcap = 1 / jCco2 (where j is the symbol indicating the imaginary part; C is the capacitance of the medium between the cylindrical conducting surface 48 and the nearby conducting element GD; and co2 is the angular frequency related to the frequency f2 of the capacitive current, co2 = 2irf2) by measuring the amplitude and phase (i.e., the angular component) of the capacitive voltage measured between the cylindrical conducting surface 48 and the nearby conducting element GD.

[0040] The inductive module 44 is arranged in a nested and close manner with respect to the capacitive module 47 inside the hollow insulating body 42 at the level of the middle part of the water / oil emulsion sensor 40. The transmitting coil 45 and the sensing coil 46 are in line and extend along the longitudinal axis LL' of the sensor. The cylindrical conductive surface 48 extends along the longitudinal axis LL' and is coaxial with the transmitting coil 45 and the detecting coil 46. The cylindrical conductive surface 48 is concentric and surrounds both the transmitting and detecting coils 45 and 46. The diameter of the cylinder defined by the cylindrical conductive surface 48 is greater than the diameter of the cylinder defined by either the transmitting coil 45 or the detecting coil 46. The length of the cylinder defined by the cylindrical conductive surface 48 is equal to or greater than the length of the cylinder defined by the transmitting and detecting coils 45 and 46.In other words, the cylinder defined by the transmitting and detecting coils 45, 46 is completely enclosed within the cylinder defined by the conductive cylindrical surface 48. Consequently, the first and second investigation zones IZ1, IZ2 substantially overlap each other.

[0041] The inductive and capacitance measurements are complex impedance measurements Zind and Zcap, respectively, with phase shift. The complex impedance Z depends on (i.e., is not proportional to) the nature of the polyphase fluid mixture MF and can combine a portion of insulating fluid within a conducting fluid (this is related to the inductive complex impedance Zind) and a portion of conducting fluid within an insulating fluid (this is related to the capacitance complex impedance Zcap). The processing module 50 extracts complex impedance Z values ​​in phase (i.e., angular component) and in quadrature. Consequently, the water and oil content of the polyphase fluid mixture MF can be estimated at substantially the same location, thus forming a more compact overlapping investigation zone IZ (i.e., the zone overlapping zones IZ1 and IZ2).Furthermore, this combination of inductive and capacitive measurements in one place. substantially identical allows continuous coverage of all kinds of MF multiphase fluid mixtures circulating in the form of an emulsion.

[0042] The first and second investigation zones IZ1, IZ2 can be approximated as investigation cylinders around the inductive module 44 and the capacitive module 47, each having an investigation volume on the order of a cubic centimeter, for example from 1 cm³ to 9 cm³, extending over two to five times the diameter of the water / oil emulsion sensor 40. The diameter of the water / oil emulsion sensor 40 can be on the order of a millimeter, for example a few millimeters ranging from 4 mm to 9 mm. The length of the investigation zone along the inductive module 44 / capacitive module 47 can be on the order of a centimeter, for example from 1 cm to 4 cm. Thus, the measurements are carried out in the vicinity of the water / oil emulsion sensor 40, very close to the inductive module 44 / capacitive module 47 parts, namely around the hollow insulating body 42.

[0043] To improve the accuracy of emulsion measurements, calibration can be performed to determine the conductivity of the continuous phase (i.e., the medium) since the conductivity of water is affected by the salt content (e.g., brine is more conductive than unsalted water). This can be determined in various ways, for example, by sampling in the well or by in situ measurement.

[0044] Figures [Fig.9] and [Fig.10] are diagrams illustrating the response of the water / oil emulsion sensor in a water / oil emulsion and how this is used to infer the water content and oil content of a multiphase fluid mixture flowing as an emulsion in a hydrocarbon well.

[0045] The diagram in Figure [Fig. 9] illustrates the capacitive output Ocap (solid line) and the inductive output Oind (dashed line) from zero to an arbitrary full-scale value FS (ordinate) as a function of the percentage water content COW (abscissa). From a water content COW evolving from 0% to 50% (i.e., the dispersed phase being water in the continuous phase being oil), the capacitive output Ocap (solid line) increases until it reaches a full-scale plateau corresponding to saturation of the capacitance measurement (i.e., 50% corresponding to a continuous phase change from oil to water), while the inductive output Oind (dashed line) is zero (because the medium is insulating, i.e., the conductivity is zero). From a water content COW evolving from 50% to 100% (i.e.,(the dispersed phase being oil within the continuous phase being water), the inductive output Oind (dashed line) increases until it reaches a full-scale value at 100% water, while the capacitance output Ocap (solid line) remains at full scale (due to the medium being conductive, i.e., conductivity increases). The dashed line shows the point at which the continuous phase (medium) transitions from oil (left of the diagram; CP=O / DP=W) to water (right of the diagram; CP=W / DP=O).

[0046] The diagram in Figure [Fig. 10] illustrates the response (total output OT) when the capacitive output Ocap (solid line in Figure [Fig. 9]) and the inductive output Oind (dashed line in Figure [Fig. 9]) are combined. The summation of the two outputs can be performed analogically with an operational amplifier or digitally by the processing module 50. The result is a nonlinear response that can be approximated by an nth-order polynomial. The processing module 50 of the water / oil emulsion sensor 40 determines the water and oil content of the multiphase fluid mixture MF flowing as an emulsion in the investigation zone IZ based on data measured by the inductive power supply and measurement module 51 connected to the inductive module 44, and the capacitive power supply and measurement module 52 connected to the capacitive module 47.When a water / oil emulsion sensor 40 of the invention is moved inside a hydrocarbon well, the measurement log is used to determine the water and oil content of the water / oil emulsion. The log can be interpreted to determine sections of said well where the water / oil emulsion is more or less conductive or other sections of said well where the water / oil emulsion is more or less capacitive, so that the interpretation of the log helps to estimate the oil-in-water ratio in order to locate oil-producing zones, and the water-in-oil ratio in order to locate water-producing zones.

[0047] Figure [Fig.4] is a partial cross-sectional side view illustrating a water / oil emulsion sensor 40 of the invention according to a second embodiment. The second embodiment differs from the first embodiment illustrated in Figure [Fig. 3] only in that the sensor 40 further comprises an active counter electrode 54A, 54B having a first part 54A and a second part 54B on either side of the cylindrical conductive surface 48. Each of the first part 54A and second part 54B is a ring having essentially the same diameter as the cylindrical conductive surface 48. The two parts of the active counter electrode 54A, 54B are connected to a reverse voltage supply 53 which provides the active counter electrode 54A, 54B with a reverse voltage vr relative to the capacitive excitation voltage vl applied to the cylindrical conductive surface 48 by the capacitive power supply and measurement module 52.This arrangement allows the field lines of the capacitive module 47 to be focused, providing substantially straight field lines, at least straighter than in the first embodiment. Consequently, the superimposed investigation area IZ according to the second embodiment is even more compact and well-defined.

[0048] Figures [Fig. 11], [Fig. 12] and [Fig. 13] are respectively a side perspective view, a lateral cross-sectional view and a front view illustrating various embodiments of a downhole tool, in particular a well logging tool. production 1, comprising a network of water / oil emulsion sensors 40 according to the invention. The production logging tool 1 is intended to be deployed in any section of the hydrocarbon well, for example in the inclined well section and the horizontal well section shown in Figure [Fig.1].

[0049] The production logging tool 1 has an elongated cylindrical body shape and comprises a central rigid, pressure-resistant housing 10 carrying a centering arrangement IL. The production logging tool 1 extends longitudinally around the longitudinal axis XX'. The centering arrangement 11 substantially centers the production logging tool 1 with respect to the borehole axis YY' during operations in the borehole, the longitudinal axis XX' of the production logging tool 1 being substantially parallel, generally coinciding or coincident with, the borehole axis. When the production logging tool 1 is moved along the borehole, the centering arrangement 11 is adapted to fit boreholes of different diameters while providing minimal frictional resistance.

[0050] The central rigid pressure-resistant housing 10 comprises, at one end, a first housing portion 13 which may include the main processing module 59 or a portion 59A of the main processing module, at the other end, a second housing portion 14 which may include another portion 59B of the main processing module and / or other electronic modules, and, in the center, a rod 15 in the form of an elongated hollow tube of reduced diameter connecting the first and second housing portions 13, 14. The main processing module 59, 59A, 59B is used here as generic terminology and may provide various electronic functions, for example, calculations, power supply, telemetry, positioning, etc. It may include microprocessors, power components, batteries, depth sensors and positioning sensors, etc.In particular, positioning sensors may include accelerometer and gyroscopic sensors that allow measurement of tool inclination and relative azimuth and, consequently, the positions of downhole fluid property analysis probes in the well section relative to the top and bottom.

[0051] The centering arrangement 11 comprises articulated centering arms 12 (six articulated centering arms in this example) and associated roller hinges 17. The roller hinges 17 are positioned outside the articulated centering arms 12 and the rod 15 and contact the wall 6 of the hydrocarbon well 2 (see Figures [Fig. 1] and [Fig. 2]). In particular, the roller hinges 17 are adapted for low-friction, drag contact with the wall 6. Each articulated centering arm 12 comprises a first arm portion and a second arm portion coupled together by the associated roller hinges 17, forming a appropriate pivot joint. The first centering arm portion and the second centering arm portion may be identical. The centering arms 12 are coupled on one side to the first housing portion 13 of the housing 10 by a respective pivot joint, e.g., hinges 18, and on the other side to a sliding sleeve 21 by a respective pivot joint, e.g., hinges 19. The sliding sleeve 21 may slide on the rod 15. By way of example, the present embodiment includes a centering arrangement 11 comprising six centering arms 12. The six centering arms are circumferentially spaced around the longitudinal axis XX' of the production logging tool 1. The six centering arms may be identical and equidistant around the circumference. The centering arrangement 11 further includes an axial spring element, e.g.a helical spring 24 extending around the rod 15 and being arranged as a stop between the second part of the housing 14 and the sliding sleeve 21. .

[0052] The centering arrangement 11 functions as follows. The helical axial spring 24 exerts an axial force substantially along the longitudinal axis XX' of the production logging tool 1. The axial forces act on the sliding sleeve 21 which slides on the rod 15. Thus, the helical spring 24 causes radial forces which act on the articulated centering arms 12 and the associated roller hinges 17, causing them to move radially outwards towards the wall 6 until an outermost extended position corresponding to the outermost parts of the roller hinges 17 being pushed into contact with the surface of the wall 6 (see Figure [Fig. 1]).When the production logging tool 1 is moved in a hydrocarbon well 4 whose diameter changes, particularly through a restriction of smaller diameter, the wall 6 acts on the articulated centering arms 12 and the associated roller hinges 17, which are forced to move radially inwards towards the rod 15. This causes an inwardly directed axial force acting on the sliding sleeve 21, which slides on the rod 15 in the opposite direction, compressing the helical spring 24. In an extreme configuration, adapted to the downward movement of the tool, the articulated centering arms 12 and the associated roller hinges 17 can be fully retracted so as to be parallel to the rod 15, resting on the circumferential surface of the rod, flush with the external surface of the first and second housing parts 13, 14.This sliding sleeve mechanism, including the helical axial spring 24, is a passive mechanism that allows the arms 12 to be automatically extended radially so as to be deployed across the full diameter of the well and to engage with the well wall. Alternatively, this passive sliding sleeve mechanism can be replaced by an active motorized mechanism, for example, a motor (not shown) replacing the spring and controlling the position of the sliding sleeve. An arm opening sensor (not shown). provides a measurement of the opening of arms 12 and allows the internal diameter ID of well section 2 to be deduced.

[0053] According to this embodiment, each centering arm 12 may further comprise at least one, for example multiple, water / oil emulsion sensors 40 fixed to an inner side (the inner face facing the rod 15) or to a lateral side of the centering arm 12 so as to expose each water / oil emulsion sensor 40 to the multiphase fluid mixture MF flowing in the hydrocarbon well 4, and at the same time protect each sensor from damaging direct contact with the well wall 6. Each water / oil emulsion sensor 40 is fixed to the corresponding centering arm 12 by means of suitable probe fixings 25 on the side of the centering arms. By way of example, each probe fixing 25 may be a metal band tightly surrounding the sensor body and fixed to the arm by means of a screw and a tapped hole for easy mounting and dismounting.This configuration helps to reduce the risk of damage to the sensors during logging and / or deployment. Each water / oil emulsion sensor 40 is connected to the main processing module 59, or to parts of the main processing module 59A, 59B in the first part of the housing 13 and / or in the second part of the housing 14. A protective cable (not shown for clarity) enclosing all the wires (power wires, communication wires, I / O wires, etc.) extends from the main processing module 59, 59A, 59B to the water / oil emulsion sensor 40 through pressure feedthroughs in said housing part 13, 14 and along the centering arms 12. Optionally, other sensors or probes, for example a downhole fluid properties analysis probe 60 of any type, namely mechanical, magnetic, optical, piezoelectric, electrical, ultrasonic, turbine or mini-turbine, etc.Sensors sensitive to various physical entities such as pressure, temperature, density, viscosity, refractive index, fluid velocity, bubble number and gas retention, fluorescence, spectroscopic absorption, etc., can be further fixed to the inner or lateral side of the centering arm 12. For example, in a particular tool configuration, the sensors or probes 60 are optical probes measuring gas retention, a mini-turbine probe measuring fluid velocity, an ultrasonic Doppler probe measuring fluid velocity, etc. Water / oil emulsion sensors 40 and other downhole fluid property analysis probes 60 of any type or a combination of several types can form a sensor array.

[0054] Multiple water / oil emulsion sensors 40 and / or downhole fluid property analysis probes 60 can be connected together to the main processing module 59 to form a sensor network. The network of water / oil emulsion sensors and / or downhole fluid property analysis probes of The 60 wells can be connected together to form a star array of water / oil emulsion sensors. This improves reliability because all sensors are independently connected to the main processing module 59, meaning a failing sensor has no effect on any other. The network of water / oil emulsion sensors and / or downhole fluid property analysis probes from the 60 wells can be connected together to form a sensor chain. This simplifies cable connections because all sensors are connected to each other at the main processing module 59 via a single connection chain.

[0055] Figure [Fig. 14] is a side-view perspective illustrating another embodiment of a downhole tool, in particular a production logging tool 1, comprising a water / oil emulsion sensor 40 of the invention. The production logging tool 1 according to this other embodiment is intended to be deployed in a vertical section of a hydrocarbon well as shown in Figure [Fig. 2].

[0056] The production logging tool 1 has an elongated cylindrical body shape and includes a central rigid pressure-resistant housing 10. The production logging tool 1 extends longitudinally around the longitudinal axis XX'. The production logging tool 1 is coupled to surface equipment via a cable 5 (see Figure [Fig. 2]) which can be actuated at the surface equipment to move the tool along the wellbore and substantially centers the production logging tool 1 with respect to the borehole axis during operations in the borehole, the longitudinal axis XX' of the production logging being substantially parallel, generally coinciding or coincident with the borehole axis YY' of the tool 1. The central rigid pressure-resistant housing 10 includes the main processing module 59 and / or other electronic modules.The central rigid pressure-resistant housing 10 includes at least one groove 16 opening partially outwards (i.e., towards the multiphase fluid mixture) to accommodate at least one water / oil emulsion sensor 40. Optionally, the groove 16 may also accommodate other probes for analyzing the properties of downhole fluids 60 (as described above in relation to the embodiments in Figures [Fig. 11], [Fig. 12], and [Fig. 13]). In addition, other similar grooves 16 may be provided around the circumference of the central rigid pressure-resistant housing 10 (e.g., the tool shown includes four grooves).

[0057] With the production logging tool of the invention, it is possible to perform: - Precise measurements of the water and oil content of a multiphase fluid mixture flowing as an emulsion regardless of the well configuration, the well section comprising vertical, horizontal or inclined well sections. - Fluid identification measurements for the water / oil emulsion can be concentrated on the most relevant area of ​​the well, such as the production zone. - Minimal flow disturbance from the tool's structure is achieved thanks to the tool's unique mechanical design. - Interchangeable sensors for maintenance issues. - A robust design allowing deployment in open-hole sections. - The structure of the production logging tool of the invention is simple and compact, resulting in low cost, and easy operation and maintenance.

[0058] It should be noted that the embodiments of the production logging tool according to the present invention are not limited to the embodiment showing a horizontal and vertical hydrocarbon wellbore, the invention being also applicable regardless of the wellbore configuration, namely inclined or a succession of inclined and / or horizontal portions, cased or uncased. Furthermore, the water / oil emulsion sensor of the invention is not limited to application in a production logging tool, but can be readily adapted to various applications in analytical tools operating under downhole pressure and temperature conditions, e.g., a downhole fluid analysis tool, a cable tool, or a formation tester.Although the illustrated production logging tool comprises only a single measuring section, the principle of the invention would also be applicable to a production logging tool comprising several interconnected measuring sections. Furthermore, the downhole tool comprising one oil / water emulsion sensor per arm, as illustrated, is a non-limiting embodiment, as more or fewer oil / water emulsion sensors can be provided depending on the required level of accuracy, the available space along the deployment arm(s), and any other considerations related to the deployment of such downhole tools in specific hydrocarbon wells.Furthermore, despite the fact that some of the drawings show sections of the hydrocarbon well filled with emulsion, the invention is also applicable for performing multiphase flow measurements in highly inclined well sections and substantially horizontal well sections (well axis YY') in which the multiphase fluid mixture flows as a layered flow in the well sections, for example a layer of gas flowing over an oil and water emulsion (the continuous phase being either water or oil).

Claims

1. Demands A water / oil emulsion sensor (40) sensitive to the water and oil content of a multiphase fluid (MF) mixture flowing as an emulsion in a hydrocarbon well (2), the water / oil emulsion sensor (40) comprising: - a conductive tip (41) at a front part, a hollow insulating body (42) at a middle part and a hollow conductive body (43) at a rear part, said front part having a conical shape, said middle and rear parts having a substantially cylindrical shape, said parts of said sensor being coaxial, extending along a longitudinal axis (LL1) and being assembled in a sealed manner, - an inductive module (44) housed in the hollow insulating body (42) and comprising a transmitting coil (45) and a detecting coil (46), - a capacitive module (47) housed in the hollow insulating body and comprising a conductive cylindrical surface (48), and - an electronic unit (49) comprising a processing module (50) coupled to an inductive power supply and measurement module (51) connected to the inductive module (44), and to a capacitive power supply and measurement module (52) connected to the capacitive module (47), in which: - the inductive power supply and measurement module (51) is arranged to inject an excitation inductive current (il) into the transmitting coil (45) such that if the multiphase fluid mixture (MF) is conductive, a first induced inductive current (i2) is generated in a first investigation zone (IZ1) surrounding the inductive module (44) and a second induced inductive current (i3) proportional to the first induced inductive current (i2) is measured in the detection coil (46), the second induced inductive current (i3) being representative of the water content within the multiphase fluid mixture (MF) in the first investigation zone (IZ1), - the capacitive power supply and measurement module (52) is arranged to apply a capacitive excitation voltage (vl) to the conductive cylindrical surface (48) and to measure a capacitance of the multiphase fluid mixture (MF) in a second investigation zone (IZ2) surrounding the conductive cylindrical surface (48), the capacitance being representative of the oil content within the multiphase fluid mixture (MF) in the second investigation zone (IZ2), - the inductive module (44) is arranged in a nested manner and close to the capacitive module (47) inside the hollow insulating body at the mid-section, the transmitting coil (45) and the detecting coil (46) being in line and extending along the longitudinal axis (LL1), the conductive cylindrical surface (48) being coaxial with the longitudinal axis (LL1), concentric and surrounding both the transmitting and detecting coils (45,46) such that the first and second investigation zones (IZ1, IZ2) overlap substantially so that the water and petroleum content of the multiphase fluid mixture (MF) flowing as an emulsion can be determined at a substantially identical location (IZ).

2. The water / oil emulsion sensor (40) according to claim 1, wherein the conductive tip (41) and the hollow conductive body (43) are made of a metallic alloy resistant to well conditions, and the insulating hollow body (42) is made of ceramic.

3. The water / oil emulsion sensor (40) according to any one of claims 1 to 2, wherein each of said transmitting coil (45) and sensing coil (46) comprises a core consisting of a hollow ferrite cylinder or torus, and a winding comprising several turns of a metallic wire.

4. The water / oil emulsion sensor (40) according to any one of claims 1 to 3, wherein the inductive power supply and measurement module (51) is arranged to inject an inductive excitation current (il) having an amplitude from 0.1 mA to 20 mA and a frequency (fl) ranging from 1kHz to 900kHz in the transmitting coil (45).

5. The water / oil emulsion sensor (40) according to any one of claims 1 to 4, wherein the capacitive power supply and measurement module (52) is arranged to apply a capacitive excitation voltage (vl) having an amplitude from 100mV to 9V and a frequency (f2) from 1kHz to 900kHz to the cylindrical conductive surface (48).

6. The water / oil emulsion sensor (40) according to any one of claims 1 to 5, wherein the cylindrical conductive surface (48) is supported on a support tube (48A), said cylindrical conductive surface (48) being made of metal, said support tube (48A) being made of a plastic or ceramic material.

7. The water / oil emulsion sensor (40) according to any one of claims 1 to 6, wherein the conductive tip (41) is connected to a ground potential (GD) by means of a tip wire (57), the tip wire (57) closing a loop between the conductive tip (41) and the hollow conductive body (43).

8. The water / oil emulsion sensor (40) according to any one of claims 1 to 7, further comprising a connector (56) positioned at the rear of said sensor (40) so as to close the hollow conductive body (43) at one side of the sensor opposite the conductive tip (41).

9. The water / oil emulsion sensor (40) according to any one of claims 1 to 8, wherein the processing module (50) is arranged to extract complex impedance (Z) values ​​in angular phase and quadrature from complex inductance (Zind) values ​​provided by the inductive power and measurement module (51) connected to the inductive module (44) combined with complex capacitance (Zcap) values ​​provided by the capacitive power and measurement module (52) connected to the capacitive module (47) and estimate the water and oil content on the basis of an experimental model fitted by a polynomial approximation.

10. The water / oil emulsion sensor (40) according to any one of claims 1 to 9, further comprising an active counter electrode (54A, 54B) having a first part (54A) and a second part (54B) on each side of the cylindrical conductive surface (48), each of said parts (54A, 54B) being a ring having essentially the same diameter as the conducting cylindrical surface (48), the two parts (54A, 54B) being connected to a reverse voltage supply (53) supplying the active counter electrode (54A, 54B) with a reverse voltage (vr) compared to a capacitive excitation voltage (vl) applied to the conducting cylindrical surface (48) by the capacitive power supply and measurement module (52).

11. A downhole tool (1) comprising an elongated cylindrical body (10) with longitudinal axis (XX1), said body (10) carrying a centering arrangement (11) comprising articulated centering arms (12), said arms (12) being actuated from a retracted configuration to a radially extended configuration, in which at least one arm carries at least one water / oil emulsion sensor (40) according to any one of claims 1 to 10.

12. A downhole tool (1) comprising an elongated cylindrical body (10) with longitudinal axis (XX1), the body (10) comprising at least one groove (16) opening partially externally to house at least one water / oil emulsion sensor (40) according to any one of claims 1 to 10.

13. The downhole tool (1) according to claim 11 or 12, wherein multiple water / oil emulsion sensors (40) are connected to a main processing module (59) so as to form a sensor network.

14. The downhole tool (1) according to any one of claims 11 to 13, further comprising another downhole fluid property analysis probe (60), selected from the group comprising sensors sensitive to physical parameters such as pressure, temperature, density, viscosity, refractive index, fluid velocity, bubble number and gas retention, fluorescence, spectroscopic absorption of the multiphase fluid mixture (MF).

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