Production logging tool and downhole fluid analysis probes deploying method

A guiding sub-section (2) of a production logging tool (1) comprises a central rigid stem (30) having a first mechanical connector (33) at one end and a second mechanical connector (34) at an another end, and carrying a roller deploying arrangement (31) comprising multiple external articulated arms (35A, 35B, 35C) circumferentially distributed about said body, each articulated arm comprising a roller assembly (32A, 32B, 32C) adapted for contact with a wall (7) of the hydrocarbon well (4) and operable from a retracted configuration into a radially extended configuration. The roller assembly (32A, 32B, 32C) comprises an arm hinge (51) coupling a first arm part and a second arm part of each articulated arm (35A, 35B and 35C) and having an arm hinge axis (AA′) substantially perpendicular to the longitudinal axis (XX′), a roller bearing (52) secured onto the arm hinge (51) and having a roller axis (BB′) angled with respect to the hinge axis (AA′), and an anti-slippage friction roller (53) received onto the roller bearing (52) in a rotation free manner.

TECHNICAL FIELD

The invention relates to a production logging tool and a downhole fluid analysis probes deploying method. Such a production logging tool is used to analyze a multiphase fluid mixture flowing from a hydrocarbon bearing zone into a hydrocarbon well. Such a production logging tool is adapted to be deployed in a hydrocarbon well comprising vertical sections, deviated well sections, horizontal well sections or a combination of the above. Production logging tools typically operate in the harsh downhole environment of hydrocarbon wells at downhole pressure (typically in the range of one hundred to 2000 bars) and temperature (typically in the range of 50 to 200° C.) conditions, and in corrosive fluids.

BACKGROUND

During the production of a hydrocarbon well, it is necessary to monitor various characteristic parameters, like the relative volumetric flow rates of the different phases (e.g. oil, gas and water) of the multiphase fluid mixture flowing into the pipe of the well from the hydrocarbon bearing zones. Further, current hydrocarbon wells often comprise a vertical well section, deviated well sections and sometimes horizontal well sections. The interpretation of the flow in such complex wells is challenging because small changes in the well deviation and the flow regime influence the flow profile. Thus, an accurate monitoring requires sensors or probes capable of imaging a surface section or a volume section of the pipe and providing an estimation of the surface section or the volume section occupied by each phase.

Production logging of hydrocarbon wells (e.g. oil and gas wells) has numerous challenges related to the complexity of the multiphasic flow conditions and the harshness of the downhole environment.

Gas, oil, water, mixtures flowing in wells, being either openhole or cased hole wells, will present bubbles, droplets, mist, segregated wavy, slugs structures depending on the relative proportions of phases (“holdup”), their velocities, densities, viscosities, as well as pipe dimensions and well deviations. In order to achieve a good understanding of the individual phases flowrates and determine the relative contributions of each zone along the well, an accurate mapping of fluids types and velocities is required over the whole section of the hole (openhole well portion) or pipe (cased well portion) at different depths (i.e. the measured depth is different from the true vertical depth and generally longer than true vertical depth, due to intentional or unintentional curves in the well).

Further, production issues greatly vary depending on reservoir types and well characteristics resulting in the need for a flexible production logging technology working with different types of sensing physics. For example, due to the phases segregation, deviated wells showing high water cuts require an accurate detection of thin oil layer at the uppermost portion of the pipe. Well deviation will have a strong impact on velocities and holdups.

Furthermore, high pressure, up to 2000 bars, high temperature, up to 200° C., corrosive fluid (H2S, CO2) put constraints on sensors and tool mechanics.

Furthermore, solids presence in flowing streams can damage equipments. In particular, the sand entrained from reservoir rocks will erode parts facing the fluid flow. Solids precipitated from produced fluids due to pressure and temperature changes, such as asphalthenes, paraffins or scales create deposits contaminating sensors so and/or blocking moving parts (e.g. spinners).

Furthermore, the tool deployment into the well can be difficult and risky. In highly deviated or horizontal wells, tools must be pushed along the pipe using coiled tubing or pulled using tractor which is difficult when tools are long and heavy. Pipes may be damaged by corrosion or rock stress which may create restrictions and other obstacles. During the logging operation, equipments can be submitted to high shocks. Thus, in such environments, it is highly preferable to have light and compact tools.

Furthermore, the cost is also an important parameter in order to provide an economically viable solution to well performance evaluation even in mature fields having low producing wells in process of depletion with critical water production problems.

With respect to the hereinbefore described challenges, the state of the art production logging equipments have limitations.

Certain production logging tools available on the market have limited or no pipe section imaging capabilities and work correctly only in near vertical wells. These tools use a gradiomanometer and/or capacitance sensor to identify fluid entries. Further, these tools use spinner rpm and insitu calibration data to compute holdups and flowrates.

Other production logging tools available on the market are intended to identify fluid types from local probe sensors (electrical or optical) and to compute the fluid velocities from miniaturized spinners. Some of these production logging tools comprise probes attached to the centralizer arms creating a two dimensional (2D) array of local measurements. Achieving sufficient coverage requires a large number of arms/probes which leads to complex and expensive designs, and complex tool maintenance. In addition, the measurements on different phases are made at different positions on a long tool string resulting in interpretation issues. Another production logging tool comprises a one dimensional (1D) array of sensors attached to a moving arm providing a scan of measurements along one line of the pipe section. Thus, the measurements coverage is limited and, depending on tool position, some production zone may be missed. The operation of such complex and costly tools results in important deployment difficulties that render compulsory the presence of highly trained engineering teams on the field.

Other attempts have been made to develop tools with rotating arms in order to improve coverage. The documents U.S. Pat. Nos. 5,531,112 and 5,631,413 describe a production logging tool for use within a well to determine fluid holdup of a multiphase fluid flow within the well. The production logging tool includes a plurality of sensors secured within a plurality of arms which radially extend from a tool housing to points distal from the tool housing. A plurality of sensors are included within the plurality of arms for detecting variations in fluid properties attributable to different flow constituents of the multiphase fluid flow along a path which circumscribes an exterior of the tool housing. The plurality of arms are rotated about the tool housing for moving these sensors through the path in order to ensure that the volumetric proportions of the different flow constituents of the multiphase fluid flow are accurately detected in highly deviated and in horizontal wells. Such production logging tools are complex apparatuses. Their reliability is problematic when taking into account the harsh downhole environment of hydrocarbon wells. In particular, the difficulty of operating motor/shafts mechanics under high pressure and complexity of rotating electrical connections kept such development at prototype level and technology has never been commercialized.

SUMMARY OF THE DISCLOSURE

It is an object of the invention to propose a production logging tool that overcomes one or more of the limitations of the existing apparatus, in particular that is structurally simple and reliable to operate whatever the downhole conditions.

According to one aspect, there is provided a guiding sub-section of a production logging tool, the production logging tool comprising a measuring sub-section provided with probe to analyze at least one property of a multiphase fluid mixture flowing in a hydrocarbon well, the guiding sub-section has an elongated cylindrical body shape of longitudinal axis and comprises a central rigid stem having a first mechanical connector at one end and a second mechanical connector at an another end, at least one being arranged to be coupled with said measuring sub-section, and carrying a roller deploying arrangement comprising multiple external articulated arms circumferentially distributed about said body, each articulated arm comprising a roller assembly adapted for contact with a wall of the hydrocarbon well and operable from a retracted configuration into a radially extended configuration, the centralizer arms being coupled at a first side to the first mechanical connector and at a second side to a sliding sleeve arranged to slide on the central rigid stem, an axial spring extending around the central rigid stem and being disposed in abutment between the second mechanical connector and the sliding sleeve, wherein the roller assembly comprises:

an arm hinge coupling a first arm part and a second arm part of each articulated arm and having an arm hinge axis substantially perpendicular to the longitudinal axis;

a roller bearing secured onto the arm hinge and having a roller axis angled with respect to the hinge axis; and

an anti-slippage friction roller received onto the roller bearing in a rotation free manner;

such that running the production logging tool in the hydrocarbon well results in a rotation movement of the guiding sub-section and of the measuring sub-section about the longitudinal axis.

The roller axis may be angled with respect to the hinge axis according to an angle ranging from 5° to 25°.

The roller bearing may comprise an inclined through-hole to receive the arm hinge such as to set the angle.

The roller bearing may comprise an abutting head laterally blocking one side of the anti-slippage friction roller, the abutting head being provided with a locking pin engaging a hole into one part of the associated articulated arm such as to block the rotation of the roller bearing and set the angle at a determined value.

A flat ring and a retaining ring may be provided at another side of the anti-slippage friction roller, the retaining ring being snapped into place into a machined groove in the roller bearing laterally blocking another side of the anti-slippage friction roller.

The arm hinge may secure in place a first arm part and a second arm part of each articulated arm by a head on one side and hole/pin on the other side.

The anti-slippage friction roller may be a notched wheel, or a wheel comprising multiple teeth, or a wheel comprising multiple pins, or a wheel comprising multiple spikes so as to have a frictional engagement with the surface of the wall.

The guiding sub-section may further comprise an unhooking blade having an end secured to the central rigid stem and associated with a respective articulated arm and arranged to initiate or ease the unhooking of the articulated arms from the central rigid stem when the guiding sub-section proceeds from a retracted configuration to the radially extended configuration.

The guiding sub-section may further comprise a roller assembly receiving part positioned approximately in the middle of the central rigid stem having a collar shape and comprising a central recess and at least one longitudinal outward clearance associated with a connecting rib that are arranged on the circumference of the roller assembly receiving part to receive a roller assembly and its associated articulated arm.

According to a further aspect, there is provided a production logging tool to analyze at least one property of a multiphase fluid mixture flowing in a hydrocarbon well comprising at least one measuring sub-section having an elongated cylindrical housing shape and comprising a central pressure-resistant rigid housing carrying a centralizer arrangement including a plurality of centralizer arms circumferentially distributed about said housing and operable from a retracted position into a radially extended position, at least one downhole fluid properties analysis probe being secured on an inner or lateral face of each centralizer arm such as to expose a tip of said, at least one, probe to the multiphase fluid mixture flowing in the hydrocarbon well, wherein the production logging tool further comprises at least one guiding sub-section according to the invention.

According to still a further aspect, there is provided a method of deploying a production logging tool in a hydrocarbon well, comprising the steps of:

providing a production logging tool extending along a longitudinal axis comprising a measuring sub-section and a guiding sub-section, the measuring sub-section carrying a centralizer arrangement including a plurality of centralizer arms circumferentially distributed about said longitudinal axis and operable from a retracted position into a radially extended position of engagement with a wall of the well, at least one downhole fluid properties analysis probe being secured on an inner or lateral face of each centralizer arm such as to expose a tip of said, at least one, probe to a multiphase fluid mixture flowing in the hydrocarbon well, the guiding sub-section carrying a guiding arrangement including a plurality of articulated arms circumferentially distributed about said longitudinal axis and operable from a retracted position into a radially extended position of engagement with a wall of the well, the articulated arms having respective radially outermost portions configured to frictionally engage the wall of the well,

running the production logging tool along the well while operating the centralizer arms and the articulated arms to radially extend into engagement with the wall of the well and to cause anti-slippage friction between said outermost portions of the articulated arms and the wall of the well, said outermost portions of the articulated arms are configured to cause the production logging tool to rotate around the longitudinal axis as a result of the running of the production logging tool along the well.

The outermost portions may be configured to rotate with respect to the respective articulated arms as a result of said friction around an axis angled with respect to the longitudinal axis of the production logging tool.

The production logging tool of the invention enables rotating the whole production logging tool, thus rotating the probes attached to it when the production logging tool is run into the well (the displacement of the tool results from the traction exerted by the cable or the coiled tubing). This rotation is obtained in a passive manner, namely without a specific motor/shaft mechanism within the production logging tool, but rather as a result of the upward (i.e. towards the surface of the well) or downward (i.e. towards the bottom of the well) movement of the production logging tool. This results in a simple and compact structure achieving low cost, easy operation and maintenance.

Further, the particular helicoidal movement of the probes (i.e. magnetic, optical, electrical, or ultrasonic type, or a combination of at least two of these types) that is obtained enables scanning circumference of the hydrocarbon well section in an efficient manner, therefore achieving a substantial coverage of the wellbore section and detecting thin layers of fluids produced while using a few number of probes. This is particularly advantageous in deviated and horizontal hydrocarbon well where fluid mixture (oil, gas, water) flows in a highly segregated manner.

Other advantages will become apparent from the hereinafter description of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a perspective view schematically illustrating a production logging tool (PLT)1deployed into a well bore of a hydrocarbon well4that has been drilled into an earth subterranean formation5. The production logging tool1comprises at least one guiding section2, for example two guiding sections, namely a first2A and a second2B guiding section as depicted inFIG. 1, and a measuring section3that is used to analyze at least one property of a multiphase flow mixture MF flowing in the hydrocarbon well4. The well bore refers to the drilled hole or borehole. The borehole refers to the inside diameter of the wellbore wall, the rock face that bounds the drilled hole. The open hole refers to the uncased portion of a well. While most completions are cased, some are open, especially in horizontal wells where it may not be possible to cement casing efficiently. The production logging tool1is suitable to be deployed and run in the well bore of the hydrocarbon well4for performing various analysis of the multiphase flow mixture MF properties in the hydrocarbon well. The production logging tool1comprises various sub sections having different functionalities and may be coupled to surface equipments through a wireline6(alternatively a coiled tubing). At least one sub section being herein referred as a measuring section3comprises a measuring device generating measurements logs, namely measurements versus depth or time, or both, of one or more physical parameters in or around the well4. Wireline logs are taken downhole, transmitted through the wireline6to surface and recorded there, or else recorded downhole and retrieved later when the instrument is brought to surface. There are numerous log measurements (e.g. electrical properties including conductivity at various frequencies and permittivity, sonic properties, optical properties, active and passive nuclear measurements, dimensional measurements of the wellbore, formation fluid sampling, formation pressure measurement, etc. . . . ) possible while the production logging tool1is displaced along and within the hydrocarbon well4drilled into the subterranean formation5. Surface equipments are not shown and described in details herein. In the following the wall of the well bore irrespective of being a cement wall or a metal pipe nature is referred to wall7. Various fluid (that may include solid particles) entries F1may occur from the subterranean formation5towards the well bore4. Once in the well bore4, these fluid forms a multiphase flow mixture MF that generally is driven to flow towards the surface. In particular, in deviated or horizontal wells, the multiphase fluid mixture MF may be segregated. For example, the segregated multiphase flow mixture MF may flow as a layer of gas above a layer of oil, further above a layer of oil and water mixture from top to bottom (i.e. in the direction of earth gravity).

The measuring section3and the guiding section2of the production logging tool1will now be described in details.

The measuring section3of the production logging tool1has an elongated cylindrical body shape and comprises a central pressure-resistant rigid housing10carrying a centralizer arrangement11. The production logging tool1extends longitudinally about the longitudinal axis XX′. The centralizer arrangement11substantially centers the production logging tool1with respect to the well bore axis during operations into the well bore, the well bore axis being substantially parallel, generally coincident or mingled with the longitudinal axis XX′ of the production logging tool1. The centralizer arrangement11may further position probe12tips around a circumference close to the wall7. Further, when the production logging tool1is moved along the well bore, the centralizer arrangement11is adapted to fit boreholes of different diameters while offering a minimal frictional resistance as explained hereinafter.

The central pressure-resistant rigid housing10comprises, at one end, a first housing part13including a master and telemetry electronic module and probe electronic modules, at another end, a second housing part14that may include another master and telemetry electronic module and other probe electronic modules, and, centrally, a stem15under the form of an elongated, reduced diameter, hollow tube connecting the first and second housing parts13,14. As an example, the stem15may be connected to the housing parts13,14by welding or a threaded connection. Both first and second housing part13,14may be fitted with a corresponding pin connector connected to the corresponding master and telemetry electronic module, respectively. Various connections enabling data transfer or power transfer between the various electronic components of the various sections are provided. The master and telemetry electronic module may comprise accelerometer and gyrometer sensors which allow the measurement of tool inclination and relative bearing and, consequently, positions of downhole fluid properties analysis probes within the well section with respect to top and bottom.

The centralizer arrangement11comprises articulated centralizer arms16and associated bows17. The bows17are positioned externally with respect to the articulated centralizer arms16and to the stem15and enter into contacting engagement with the wall7of the hydrocarbon well4at outermost portions of the bows. In particular the bows17are adapted for a smooth and low frictional drag contact with the wall7. Each articulated centralizer arm16includes a first arm part and a second arm part coupled together by an appropriate pivot connection, e.g. a hinge18at one of their ends. The first centralizer arm part and the second centralizer arm part may be identical. The centralizer arms16and bows17are coupled at a first side to the first housing part13of the housing10by respective pivot connection, e.g. hinges19,20and at a second side to a sliding sleeve21by respective pivot connection, e.g. hinges22,23. The sliding sleeve21can slide on the stem15. As an example, the present embodiment comprises a centralizer arrangement11including four centralizer arms16and their respective bows17. The four centralizer arms are spaced apart circumferentially about the longitudinal axis XX′ of the production logging tool1. The four centralizer arms may be identical and equally spaced on the circumference. The centralizer arrangement11further comprises an axial spring element, e.g. a first coil spring24extending around the stem15and being disposed in abutment between the second housing part14and the sliding sleeve21.

The centralizer arrangement11operates as follows. The coil spring24exerts an axial force substantially along the longitudinal axis XX′ of the production logging tool1. The axial forces act onto the sliding sleeve21that slides onto the stem15. Thus, the coil spring24causes radial forces that acts on the articulated centralizer arms16and associated bows17urging them to move radially outwardly toward the wall7until an outmost extended position corresponding to the outermost portions of the bows17being urged into engagement with the surface of the wall7. When the production logging tool1is run into a hydrocarbon well4having diameter that changes, in particular through a restriction of smaller diameter, the wall7acts on the articulated centralizer arms16and associated bows17that are urged to move radially inwardly towards the stem15. This causes an inwardly oriented axial force acting onto the sliding sleeve21that slide onto the stem15in the other direction compressing the coil spring24. In an extreme configuration, the articulated centralizer arms16and associated bows17may be fully retracted such as being parallel to the stem15, lying on the stem circumference surface, flush with the external surface of the first and second housing parts13,14.

According to the present exemplary embodiment, each centralizer arm16may further comprise at least one, for example two, downhole fluid properties analysis probe12secured on an internal side (the inner face facing the stem15) or on a lateral side of the centralizer arm16such as to expose a tip of said probe12to the multiphase fluid mixture MF flowing in the hydrocarbon well4, and at the same time protect the tip from a direct harmful contact with the wall7by means of the bows17. Probe attachments25at the side of centralizer arms allow positioning the probe tips close to the center of the bow spring in contact with the well bore wall7and therefore allows measuring fluid properties close to the wall while being protected from direct contact to the wall by the centralizer arms structure. This configuration allows reducing damage risks on the probes during logging and/or deployment. In the present description, a downhole fluid properties analysis probe12may be understood as a set including a probe electronic module, a pressure feed-through, a protective tube and a tip. The probe electronic module connected to the associated probe is located in the first housing part13and/or in the second housing part14. A protective tube enclosing a link extends from the electronic module to the tip through a pressure feedthrough into said housing part13,14. The downhole fluid properties analysis probe12may be of any type, namely mechanical, magnetic, optical, electrical, ultrasonic, spinner or mini-spinner, etc. . . . responsive to various physical entities like pressure, temperature, density, viscosity, conductivity, refractive index, fluid velocity, gas bubble and oil droplet counts and holdups, fluorescence, spectroscopic absorption, etc. . . . . For example, in a particular tool configuration, the probes12are conductivity probes measuring water holdup, optical probes measuring gas holdup, fluorescence probes measuring oil holdup, and mini-spinner probe measuring fluid velocity. In another exemplary tool configuration, the probes12are three phase optical probes measuring gas-oil-water holdups, and ultrasonic doppler probe measuring fluid velocity.

The first and second guiding sub-sections2A,2B of the production logging tool1are depicted in details inFIGS. 2 to 5. In particular,FIGS. 2 to 4illustrate one guiding section2according to different viewing angles in a deployed (radially extended) configuration, andFIG. 5illustrates a guiding section2in a retracted configuration.

The guiding section2of the production logging tool1has an elongated cylindrical body shape and comprises a central rigid stem30carrying a roller deploying arrangement31. The guiding section2extends longitudinally about the longitudinal axis XX′. The roller deploying arrangement31in combination with the operation of the centralizer arrangement11of the measuring section3substantially centers the guiding section2of the production logging tool1with respect to the well bore axis during operations into the well bore, the well bore axis being substantially parallel, generally coincident with the longitudinal axis XX′ of the guiding section2. The roller deploying arrangement31carries roller assemblies32A,32B,32C that are deployed in contact with the wall7. Further, when the production logging tool1is moved along the well bore, the roller deploying arrangement31is adapted to fit boreholes of different diameters while offering a good frictional resistance as explained hereinafter.

The central rigid stem30is coupled, at one end, to a first mechanical connector33and, at another end, to a second mechanical connector34. The central rigid stem30may be a reduced diameter, hollow tube. As an example, the central rigid stem30may be coupled to the first and second mechanical connector33,34by welding or a threaded connection. Both first and second mechanical connector33,34may be fitted with a corresponding pin connector enabling data transfer or power transfer between the various electronic components of the other sections, like the measuring section3for example, or with the surface via the wireline6. The central rigid stem30and/or the mechanical connectors33,34may comprise accelerometer and gyrometer sensors which allow the measurement of guiding section inclination and relative bearing and, consequently, positions with respect to top and bottom and angular positions of the production logging tool1within the well section.

The roller deploying arrangement31comprises multiple articulated arms35, for example three articulated arms35A,35B and35C as depicted. Each articulated arm35A,35B and35C comprises a roller assembly32A,32B,32C corresponding to outermost portions of the articulated arm35A,35B and35C and arranged to enter into contacting and frictional engagement with the wall7of the hydrocarbon well4. Each articulated arm35A,35B and35C includes a first arm part and a second arm part coupled together by the associated roller assembly32A,32B,32C that will be described in details with reference toFIGS. 6 to 8. The first arm part and the second arm part may be identical. Each articulated arm35A,35B and35C is coupled at a first side to the first mechanical connector33by pivot connection, e.g. hinge36and at a second side to a sliding sleeve37by pivot connection, e.g. hinge38. The sliding sleeve37can slide on the central rigid stem30. The three articulated arms35A,35B and35C are spaced apart circumferentially about the longitudinal axis XX′ of the production logging tool1. The three articulated arms35A,35B and35C may be identical and equally spaced on the circumference of the guiding section2. The roller deploying arrangement31further comprises an axial spring element, e.g. a coil spring39extending around the central rigid stem30and being disposed in abutment between the second mechanical connector34and the sliding sleeve37.

The roller deploying arrangement31further comprises at least one unhooking flexible blade40associated with one articulated arm35, for example three unhooking blades40associated with the respective articulated arms35A,35B,35C. Each unhooking blade40is secured on one side on the central rigid stem30while the other side is free to move and radially bended outwardly toward the wall7. Each unhooking blade40is associated with a respective articulated arm35A,35B,35C such as to initiate or ease the unhooking of the articulated arms35A,35B,35C from the central rigid stem30when the guiding section2proceeds from a retracted configuration (FIG. 5) to a deployed configuration (FIGS. 2-4).

The roller deploying arrangement31further comprises a roller assembly receiving part41positioned approximately in the middle of the central rigid stem30. The roller assembly receiving part41is a collar having a radial extension similar to the first and second mechanical connector33,34and to the sliding sleeve37. The roller assembly receiving part41comprises a central recess42and at least one longitudinal outward clearance43associated with a connecting rib44that are arranged on the circumference of the roller assembly receiving part41to receive a roller assembly32and associated articulated arm35. In the depicted embodiment, the roller assembly receiving part41comprises three longitudinal outward clearances43and three associated connecting rib44. Each of the longitudinal outward clearances43emerges internally in the central recess42. Each end of each connecting rib44is secured to the respective part of the central rigid stem30. The three longitudinal outward clearances43may be identical and equally spaced on the circumference of the roller assembly receiving part41such as to face the respective roller assembly32and associated articulated arm35. Their positions and sizes are such that the roller assemblies32and associated articulated arms35can move free of obstruction from the stem30towards the wall7and vice-versa. Further, in the retracted configuration, the outermost portions of the roller assemblies32and associated articulated arms35are flush with the first and second mechanical connector33,34and the sliding sleeve37as depicted inFIG. 5. Practically, the central recess42and the longitudinal outward clearances43may be machined in a cylindrical block of metal defining the roller assembly receiving part41.

FIGS. 6 and 7are perspective views of a roller assembly32.FIG. 8is an exploded perspective view of a roller assembly32. All the roller assemblies32A,32B,32C depicted inFIGS. 1-5are similar. The roller assembly32has different functions. A first function is to couple together a first arm part and a second arm part of each articulated arm35A,35B and35C. A second function is to tilt an anti-slippage friction roller with respect to the longitudinal axis XX′ and thus to induce an helicoidal rotation movement to the production logging tool1while it runs into the hydrocarbon well4. A third function is to frictionally engage the anti-slippage friction roller with the wall of the well such as to restrain random angular movement of the production logging tool with respect to the wall7of the well4.

The roller assembly32comprises an arm hinge51, a roller bearing52and a friction roller53. The arm hinge51defines an arm hinge axis AA′ that is generally perpendicular to the longitudinal axis XX′. The roller bearing52defines a roller axis BB′ that forms an angle α with the hinge axis AA′. The angle α may range from 5° to 25°. The arm hinge51secures a first arm part and a second arm part of each articulated arm35A,35B and35C in corresponding holes45provided in each of said arms. The arm hinge51is blocked in place by a head58on one side and hole/pin59on the other side. The roller bearing52is secured onto the arm hinge51. More precisely, the roller bearing52comprises a through-hole54to receive the arm hinge51. The through-hole54is inclined within the roller bearing52in order to define the angle α. The anti-slippage friction roller53is received onto the roller bearing52such as to be free to rotate. On one side of the roller bearing52, a locking pin60is provided in an abutting head50. One end of the locking pin60may be partially received in a clearance61of the roller bearing. The other end of the locking pin60engages a hole into one of the articulated arm35part in order to block the rotation of the whole bearing whatever the radial position of the articulated arm35. In this way, the angle α is set at a determined value. On the other side of the roller bearing52, a flat ring55and a circlip56are provided. The circlip56is a retaining ring consisting of a semi-flexible metal ring with open ends which can be snapped into place into a machined groove57made into the roller bearing52. The abutting head50, the flat ring55and the circlip56block the lateral movement of the anti-slippage friction roller53while allowing free rotation of the anti-slippage friction roller53about the BB′ axis of the roller bearing52. As an example, the roller bearing52can be made of bronze, while the other elements of the roller assembly are made of stainless steel.

The anti-slippage friction roller53may be implemented in the form of various wheel.FIGS. 6 to 8illustrate a first alternative embodiment wherein the anti-slippage friction roller53is implemented in the form of a notched wheel70. A notched wheel70is a wheel having notches72on a wheel peripheral surface71. The notches extend parallelly relatively to the roller axis BB′.FIGS. 10 and 11illustrate a second alternative embodiment wherein the anti-slippage friction roller53is implemented in the form of a toothed wheel73comprising multiple teeth74on the wheel peripheral surface71. The teeth extend radially relatively to the roller axis BB′. For example, each tooth74is removable, e.g. by being screwed in a corresponding threaded cavity75. As further alternatives, the teeth may be spikes or pins. Such notches, tooth, spikes and pins offer a good frictional engagement with the surface of the wall7. A good frictional engagement means that the notches, tooth, spikes and pins may be able to bite on (i.e. engage) the surface of the wall7without damaging the wall. Thus, lateral shifting or lateral slippage of the wheel against the surface of the wall7is prevented, at least reduced in an important manner. The wheel is therefore an anti-slippage wheel that is adapted to the particular harsh downhole conditions of hydrocarbon wells.

The roller deploying arrangement31operates as follows. The coil spring39exerts an axial force substantially along the longitudinal axis XX′ of the guiding section2of the production logging tool1. The axial forces act onto the sliding sleeve37that slides onto the central rigid stem30. Thus, the coil spring39causes radial forces that acts on the articulated arms35A,35B,35C urging them to move radially outwardly toward the wall7until an outmost extended position corresponding to the roller assemblies32A,32B,32C being urged into engagement with the surface of the wall7. The articulated arms take off can be helped by the action of the unhooking blades40. When the production logging tool1is run into a hydrocarbon well4having diameter that changes, in particular through restriction of smaller diameter, the wall7acts on the roller assemblies32A,32B,32C and the articulated arms35A,35B,35C that are urged to move radially inwardly towards the central rigid stem30. This causes an inwardly oriented axial force acting onto the sliding sleeve37that slide onto the central rigid stem30in the other direction compressing the coil spring39. In an extreme configuration, the roller assemblies32A,32B,32C and the articulated arms35A,35B,35C may be fully retracted such as being parallel to the central rigid stem30. In this retracted configuration, the articulated arms35A,35B,35C lies on the stem circumference surface, flush with the external surface of the first and second mechanical connector33,34, while the roller assemblies32A,32B,32C are received in the central recess42and the longitudinal outward clearances43. The operation of the roller deploying arrangement31of each guiding sub-section2is independent to the operation of the centralizer arrangement11of each measuring sub-section3, in the sense that in a long train of sub-sections, each sub-section adapts its respective radial extension to the well bore dimension where it is positioned. Thus, transition in the diameter of the well bore can be passed smoothly.

The roller assembly32operates as follows. Reference is made toFIG. 9that illustrates the helicoidal movement of the guiding section52caused by the operation of the roller assembly32. In particular, the trajectories60A,60B,60C of each respective anti-slippage friction roller53A,53B,53C is depicted.

The roller bearing52defines a roller axis BB′ that forms an angle α with the hinge axis AA′. This causes the anti-slippage friction roller53to be orientated according to the angle α with respect to the longitudinal axis XX′. Due to this tilting of the anti-slippage friction roller53with respect to the longitudinal axis XX′ and the frictional engagement of the anti-slippage friction roller53with the wall7, a helicoidal rotation movement is induced to the guiding section2, and thus to the whole production logging tool1when the production logging tool1is run into the hydrocarbon well4.

The angle α is chosen in a range from 5° to 25° in order to define the rotation path (i.e. the length to be run through in order to achieve a complete 360° tour) and to adapt the rotation path to specific production conditions. The rotation path may be approximated by the formulae L360°=(π×well bore-pipe diameter)/tan α. As examples, a complete 360° tour for an angle α of 18° is obtained in approximately 97 cm for well bore-pipe diameter of 10 cm (approximately 4″), in approximately 193 cm for well bore-pipe diameter of 20 cm (approximately 8″), in approximately 242 cm for well bore-pipe diameter of 25 cm (approximately 10″).

According to the present embodiment depicted inFIG. 9, the rotational movement of the whole production logging tool1is obtained in a passive manner. The production logging tool1, when run, helicoidally rotates about its longitudinal axis under the combined effects of the angle α of the anti-slippage friction roller53and of the friction of the anti-slippage friction roller53on the wall7. The mechanical coupling between the guiding section2and measuring section3enables the measuring section3to follow the movement imposed by the guiding section2. Thus, the helicoidal movement of the guiding section2causes the measuring section3to have the same helicoidal movement. In practice, the tips of the probe12of the measuring section3follow trajectories similar to the trajectories60A,60B,60C. This enables exposing the tip of the probe12of the measuring section3to the multiphase fluid mixture MF flowing in the hydrocarbon well with a robust control of its radial and angular position. Further, the helicoidal movement of the tip of the probe12enables scanning an important sector with a few numbers of probes12and, thus, substantially improves the resolution of the production logging tool according to the invention. In particular, this results in the probes12sweeping the circumferential zone CZ of the well in a controlled manner. Thus, circumferential zone CZ of the hydrocarbon well4, preferably close to the wall7can be analyzed. This gives important information about the flow regime in particular in horizontal and deviated hydrocarbon well section where segregated flow regime can occur.

With the production logging tool of the invention, it is possible to achieve:

High coverage of wellbore section, probe sensors approaching contact with wall to detect presence of ultra thin phases flowing at the top or bottom of the well bore.

Fluid identification measurements can be focused on area of pipe section with most interest such as phases interfaces for accurate holdups imaging.

Velocity measurements can be focused on area of pipe section with minimal perturbations, in the bulk of phases away from interfaces.

Minimal perturbation of flow from tool structure is obtained thanks to the original mechanical structure of the tool.

Integrated inclination and azimuth.

Interchangeable roller assemblies and probes in order to adapt to specific production issues. The production logging tool can be installed with particular angle in order to define the complete 360° tour path length, and indifferently with conductive, capacitive, optical reflection, optical fluorescence, active ultrasonics, passive ultrasonics, high resolution temperature sensors.

Design compatible with all types of probe sensor such as electrical, optical, ultrasonic, high resolution temperature.

Robust design allowing deployment in openhole sections.

Operation in memory mode for operations where electrical cable telemetry is not available such as coiled tubing deployment.

Motorless operation of production logging tool helicoidal movement.

The production logging tool structure of the invention is simple, compact achieving low cost and easy operation and maintenance.

It should be appreciated that embodiments of the production logging tool according to the present invention are not limited to the embodiment showing deviated or vertical hydrocarbon well bore, the invention being also applicable whatever the configuration of the well bore, namely vertical, deviated or a succession of vertical, deviated and/or horizontal portions, cased or uncased. Also, the guiding section of the invention is not limited to an application into a production logging tool, but can be easily adapted to various applications into analysis tools operating at downhole pressure and temperature conditions, e.g. a downhole fluid analysis tool, a wireline tool, a formation tester. Despite the fact that the illustrated production logging tool comprises two guiding sections on both side of a unique measuring section, the principle of the invention would be equally applicable to one unique guiding section and/or multiple measuring sections coupled together.