Patent Publication Number: US-2022235653-A1

Title: Fluid sampling and measuring assembly and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority from Italian Patent Application No. 102019000006068 filed on Apr. 18, 2019, the entire disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     This invention relates to a fluid sampling and measuring assembly. 
     In particular, this invention relates to a sampling and measuring assembly for sampling and measuring a fluid produced or processed or injected or transported inside an underwater facility for extracting and/or producing hydrocarbons from wells, which are made in the bed of the body of and are integral parts of the underwater facility itself. 
     In the following description, “production of hydrocarbons” refers to the extraction of hydrocarbons, the processing of hydrocarbons, the processing of fluids related to the production of hydrocarbons, and the subsequent transportation thereof. 
     STATE OF THE ART 
     Underwater hydrocarbon production facilities can be located on a bed of a body of water or in intermediate positions depending on the well or well field configuration. In addition, underwater hydrocarbon production facilities can be positioned in shallow water or very deep water and in all geographical areas regardless of whether the environmental conditions are mild or extreme. 
     The recent technological developments of underwater devices suitable for operating at great depths, and the great interest of oil companies, have facilitated the feasibility of complex systems, expanded the potential of underwater production facilities, and made it possible to put facilities that also contain active process elements in water, preferably arranged on bed of the body of water, into production. The main underwater treatment processes are: single- or multi-phase pumping; compression and pumping of gaseous fluid; two-phase or three-phase separation (e.g. liquid/liquid, gas/liquid, solid/liquid, oil/water/gas); hydrocarbon or sea or reservoir water treatment; pumping and injection of water or gas into the well; and injection of chemicals. 
     Generally, in order to predict the behaviour of the underwater facility, mathematical models are developed that simulate the features of the underwater facility and the state of the hydrocarbon reservoir over time as a function of chemical, physical, and thermodynamic data. 
     In recent years, the complexity of mathematical models has increased due to the introduction on the underwater facility of underwater separation, pumping, and compression components, chemical additive injection technologies, and the exploitation of production products at the extreme density limits, in particular low-density gases or oils with high viscosity, low temperatures, and high pressures. 
     In order to provide solutions that accurately approximate reality, mathematical models require updated data provided by sensors/instruments permanently installed in the underwater facility and require an initial calibration that must be updated over time. In particular, said sensors/instruments make it possible to measure changes in the physical and thermodynamic properties of the fluid extracted from the hydrocarbon reservoir, such as temperature, pressure, gas/liquid fraction, water/liquid fraction, flow rate, which may change during the exploitation of the hydrocarbon reservoir. 
     Documents US 2015/204167, US 2017/002651, US 2010/059221, WO 2014/039959, US 2013/025874 and US 2013/126179 describe underwater plants for sampling and/or analysing process fluids of an underwater hydrocarbon production plant. 
     If the fluid properties are not updated and accurate, mathematical models can produce significant errors with negative consequences for the operability and efficiency of the underwater facility. It is, therefore, necessary to frequently measure some significant parameters, and to define the mathematical models based on said significant parameters. 
     In general, sampling and measuring assemblies of the prior art cannot provide accurate statistical data on fluid properties. 
     OBJECT OF THE INVENTION 
     The purpose of this invention is to provide a fluid sampling and measuring assembly that mitigates the drawbacks of the prior art. 
     In accordance with this invention, a fluid sampling and measuring assembly for taking and analysing at least one fluid sample from at least one sampling station of an underwater hydrocarbon extraction and/or production facility is provided, the sampling and measuring assembly comprising:
         a sampling and measuring module, configured to sample and analyse a fluid sample;   a picking module configured to contain the fluid sample;   at least one navigation module configured to navigate in the body of water;   at least one interface module configured to hydraulically connect the sampling station, the sampling and measuring module and the picking module; wherein the sampling and measuring module and the picking module are configured to be mechanically and hydraulically coupled to each other and to the sampling station to take and analyse the fluid sample and the picking module is configured to be coupled to the navigation module to transfer the fluid sample to an analysis laboratory;       

     the fluid sampling and measuring assembly comprising a first releasable or permanent connecting device, configured to mechanically connect the interface module and the navigation module; a second releasable connecting device configured to connect the interface module and the sampling and measuring module or the sampling station mechanically, hydraulically, electrically, and for data exchange; and a second permanent connecting device configured to connect the interface module and the picking module mechanically, hydraulically, electrically and for data exchange. 
     Thanks to this invention, at least one of the sampling and measuring assembly modules can be used for the sampling and measuring operations at different sampling stations of the same underwater facility or of different underwater facilities. 
     In addition, the sampling and measuring assembly modules are configured to be variously connected and adapted to different types of underwater facilities and/or operating modes in executing the sampling and the measuring. 
     The sampling and measuring assembly makes it possible to measure and analyse the fluid with high frequency; therefore, it makes it possible to monitor changes in the properties of fluids within an underwater hydrocarbon production facility. 
     In addition, the sampling and measuring assembly makes it possible to measure in situ and, almost simultaneously, to take samples similar and/or identical to those on which measuring is performed so as to provide statistically significant data on the multiphase properties of the fluid and to monitor the reliability of the in situ measuring. 
     The sampling and measuring assembly can, advantageously, be reconfigured to easily and quickly adapt it to a particular underwater facility. 
     In summary, the sampling and measuring assembly is flexible, automated, and able to provide reliable information. 
     In particular, the navigation module comprises an ROV and/or an AUV. 
     Thus, the navigation module is remotely controlled and able to transfer one or more modules from one sampling station to a further sampling station and/or from the bed of the body of water to the surface and vice versa. 
     In particular, the sampling and measuring assembly comprises an underwater control module, which is configured to control, implement, and manage fluid sampling and measuring operations and is connected to the sampling and measuring module and to a surface station for the transmission of signals related to the sampling and measuring operations. 
     Thus, the sampling and measuring module is able to operate autonomously even in the absence of the other modules. 
     In particular, the sampling and measuring module comprises at least one first sensor configured to generate signals related to at least one chemical-physical-thermodynamic fluid characteristic and/or at least one second sensor configured to generate a signal related to the fluid flow rate, wherein the second sensor preferably comprises a Venturi tube. 
     Thus, the sampling and measuring assembly is able to measure at least one chemical-physical-thermodynamic fluid characteristic and the fluid flow rate, and to provide the measurement results in almost real time. This makes it possible to perform assessments of the need to take fluid samples to be analysed in an equipped analysis laboratory. 
     In particular, the picking module comprises at least one container configured to contain the fluid sample. 
     Thanks to the at least one container, the fluid sample can be transported to an analysis laboratory in order to be analysed. The container enables the chemical-physical properties of the fluid sample to be preserved during transport. 
     In particular, the interface module is configured to mechanically and/or electrically connect, and/or connect for data exchange, at least two between the sampling station, the sampling and measuring module, the picking module and the navigation module. 
     Thus, it is possible to connect the sampling and measuring module, the picking module, the sampling station, and the navigation module according to different configurations. Because the sampling and measuring assembly can be reconfigured according to the needs and configuration of the underwater hydrocarbon production facility and the operating modes of the sampling and measuring assembly, it is cost-effective. 
     In particular, the sampling and measuring assembly comprises an analysis laboratory; the sampling and measuring module and the analysis laboratory being configured to perform measurements of pressure, volume, volume fractions, temperature, density, viscosity and salinity of the fluid sample. 
     Thanks to the analysis laboratory or to the sampling and measuring module, it is possible to perform measurements of the physical, chemical, and thermodynamic properties of the fluid sample. 
     In particular, the analysis laboratory is configured to perform compositional, thermodynamic, and microbiological analyses of the fluid sample and is an underwater or surface analysis laboratory. 
     Thus, the compositional, thermodynamic, and microbiological analyses of the fluid sample can be performed in a plant that is easily and quickly accessible to the benefit of sample conservation, avoiding subjecting the fluid sample to thermodynamic cycles that would alter its original properties. 
     In particular, the analysis laboratory comprises one chamber and/or gaps isolated from the outside environment and at least one MEMS and/or at least one micro-fluid chip and/or at least one miniature sensor arranged inside the isolated chamber and/or gaps. 
     Thus, the analysis laboratory is small in size and is able to autonomously manage the fluid sample analysis processes. 
     The term “MEMS” refers to a Micro-Electro-Mechanical System. More specifically, the term “MEMS” refers to a set of mechanical, electrical, and electronic devices integrated in a highly miniaturised form on the same semiconductor material substrate, which combine the functions of sensors with the functions of actuators for process management. 
     In particular, at least one navigation module is configured to transport the picking module from the sampling station to the analysis laboratory, and to transport the picking module from the analysis laboratory to the sampling station. 
     Thus, the containers are quickly and easily transported. 
     In particular, the sampling and measuring module is mechanically and hydraulically coupled, in a permanent way, to the sampling station, the first permanent connecting device being configured to mechanically connect the interface module and the navigation module. 
     Thus, it is necessary to set up a sampling and measuring module for each sampling station, while only one picking module is required, which can be coupled to all the sampling and measuring modules and transported by just one navigation module. 
     In this configuration, picking is performed only when the picking module is coupled to the sampling and measuring module, while sampling may also be performed when the picking module is not coupled to the sampling and measuring module. 
     In particular, the sampling and measuring module is mechanically and hydraulically coupled in a permanent way to the sampling station, the first releasable connecting device being configured to mechanically connect the interface module and the navigation module. 
     Thus, it is necessary to set up a sampling and measuring module for each sampling station, while only one picking module and only one navigation module is required for performing the sampling and measuring operations. 
     In this configuration, it is possible to perform sampling and measuring in different time periods, even when the navigation module is not connected to the picking module. 
     In particular, the sampling and measuring assembly comprises a third permanent connecting device, configured to connect the interface module and the sampling and measuring module mechanically, hydraulically, electrically, and for data exchange; the first permanent connecting device being configured to connect the interface module and the navigation module mechanically, electrically, and for data exchange. 
     Thus, only one sampling and measuring module and one picking module are required, these being transported between the different sampling stations by one navigation module. 
     In this configuration, the sampling and measurements are performed when the sampling and measuring module transported by the navigation module is connected to a sampling station. 
     In particular, the sampling and measuring assembly comprises a first navigation module; a second navigation module; a first interface module; a second interface module; a third permanent connecting device, configured to connect the second interface module and the sampling and measuring module mechanically, hydraulically, electrically, and for data exchange; a fourth permanent connecting device, configured to connect the second interface module and the first navigation module mechanically, electrically, and for data exchange; and a third releasable connecting device configured to connect the first interface module and the second interface module mechanically, hydraulically, electrically, and for data exchange; the first releasable connecting device being configured to mechanically connect the first interface module and the second navigation module. 
     Thus, only one sampling and measuring module and one picking module are required, these being transported between the different sampling stations by one first navigation module. 
     In this configuration, the sampling and measurements are performed when the sampling and measuring module, transported by the first navigation module, is connected to a sampling station. The second navigation module is configured to take the containers containing the fluid sample from the picking module and return the empty containers to the picking module. 
     In particular, the sampling and measuring assembly comprises a fourth releasable connecting device, which enables a releasable mechanical coupling between the interface module and the analysis laboratory, a transfer of fluids from the picking module to the analysis laboratory, and a transfer of power and signals. 
     Thus, the fluid sample can be transferred to the analysis laboratory quickly and easily, without altering its chemical-physical properties. 
     Another purpose of this invention is to provide an underwater hydrocarbon production plant that mitigates at least one of the drawbacks of the prior art. 
     According to this invention, is provided an underwater hydrocarbon production plant comprising a fluid sampling and measuring assembly as described above; and an underwater hydrocarbon extraction and/or production facility configured to couple with the sampling and measuring assembly. 
     Thanks to this invention, it is possible to perform hydrocarbon extraction and/or production operations so as to manage the production processes and to plan the maintenance and/or calibration of some components of the underwater facility on the basis of reliable information. 
     Another purpose of this invention is to provide a fluid sampling and measuring method that mitigates at least one of the drawbacks of the prior art. 
     According to this invention, a fluid sampling and measuring method for taking and analysing at least one fluid sample from at least one sampling station of an underwater hydrocarbon extraction and/or production facility is provided, the sampling and measuring method comprising:
         sampling and analysing a fluid sample using a sampling and measuring module coupled to a sampling station;   preserving a fluid sample using at least one container in a picking module coupled to the sampling and measuring module;   hydraulically connecting the sampling station, the sampling and measuring module, the picking module, and an interface module;   transferring at least one fluid sample and/or at least one between the sampling and measuring module, the picking module and the interface module, via a navigation module, to an analysis laboratory;   uncoupling the sampling and measuring assembly from the sampling station;   coupling the sampling and measuring assembly to a further sampling station; and   repeating in sequence the previous steps.       

     With this method, measurements can be performed at the same time as sampling so that these measurements are related to and statistically significant of the multiphase properties of the fluid and the degree of reliability of the in situ measurements is known. 
     In addition, it is possible to eliminate some types of flow rate meters, such as multiphase flow rate meters, installed downstream of each underwater well, as this method makes it possible to obtain the same information provided by said types of flow rate meters. 
     In particular, the method involves uncoupling the picking module from the sampling and measuring module; and transferring the picking module, and related container, to an analysis laboratory via the navigation module. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Other characteristics and advantages of this invention will become clear from the following description of the non-limiting embodiments thereof, with reference to the accompanying figures, wherein: 
         FIG. 1  is a schematic representation of an underwater hydrocarbon production plant comprising an underwater hydrocarbon production facility and a sampling and measuring assembly made in accordance with a first embodiment of this invention; 
         FIG. 2  is a schematic representation of the fluid sampling and measuring assembly of  FIG. 1 ; and 
         FIGS. 3 to 5  are schematic representations of sampling and measuring assemblies in accordance with additional embodiments of this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE FIGURES 
     With reference to  FIG. 1 , the number  1  indicates, as a whole, an underwater hydrocarbon extraction and production plant  1 . The underwater plant  1  comprises an underwater facility  2  for the extraction and production of hydrocarbons and a sampling and measuring assembly  3  of a process fluid of the underwater facility  2 . 
     In the context of this description, the term “process fluid” refers to a fluid produced or processed or transported to the surface or injected into the underwater facility during hydrocarbon extraction and/or production operations. In the following description, this process fluid will simply be referred to by the term “fluid”. 
     In the case illustrated in  FIG. 1 , the underwater facility  2  comprises two wells  4  for the extraction of hydrocarbons, from a bed  5  of a body of water; a well head  6  for each well  4 , which is positioned on the bed  5  of the body of water at the corresponding well  4 ; a collector  7 ; a pipeline  8  for each well head  6 , which hydraulically connects the well head  6  to the collector  7  enabling fluid to flow; an underwater process station  9 ; a pipeline  10  that hydraulically connects the collector  7  and the underwater process station  9 ; a surface station  11 , which partially emerges from the surface  12  of the body of water; and a pipe  13 , which enables the surface station  11  and the underwater process station  9  to be connected. In particular, the pipe  13  hydraulically connects the surface station  11  and the underwater process station  9 , to enable fluid to flow, and enables the exchange of signals between the surface station  11  and the underwater process station  9  and the transfer of power from the surface station  11  to the underwater process station  9  to power a control system and an electrical system, not shown in the attached figures. 
     According to alternative embodiments, not illustrated in the attached figures, the underwater facility comprises a spool tree coupled to a corresponding wellhead for each well. 
     The underwater facility may comprise a plurality of collectors and a plurality of pipelines for each wellhead. 
     In addition, the surface station can be set up on land. In this configuration the pipe extends in a vertical direction and connects the surface station to the underwater process station or to a collector. The underwater facility  2  comprises a plurality of sampling stations  14 , located at specific points of the underwater facility  2  and configured to be mechanically and hydraulically connected to the sampling and measuring assembly  3 . In the case illustrated, the underwater facility  2  comprises three sampling stations  14 , respectively, at the pipeline  8 , at the collector  7 , and at the underwater process station  9 . 
     In the case illustrated in  FIG. 1 , the sampling and measuring assembly  3  comprises a sampling and measuring module  15 , configured to sample and analyse a fluid sample; a picking module  16  configured to contain the fluid sample; an interface module  17 ; and an interface module  18 . 
     The interface modules  17  and  18  are configured to be coupled with each other and to connect the sampling and measuring module  15  and the picking module  16  enabling power distribution and signal exchange. 
     The sampling and measuring assembly  3  comprises an analysis laboratory  19 , which is equipped to perform chemical-physical analysis on the fluid samples taken. The analysis laboratory  19  can be set up in the surface station  11 , in accordance with an embodiment not illustrated in the attached figures, or in the body of water, near or inside the underwater facility  2 . 
     According to a variant of this invention, the analysis laboratory  19  is either integrated into one of the modules of the sampling and measuring assembly  3  or is an additional module of the sampling and measuring assembly  3 . 
     In the case illustrated in  FIG. 1 , the analysis laboratory  19  is integrated into the underwater plant  1  and can be selectively coupled to the interface module  17 . 
     The sampling and measuring assembly  3  comprises two navigation modules  20  and  21 , respectively, an AUV, which is coupled to the interface module  18  and configured to transport the sampling and measuring module  15  and the interface module  18  from one sampling station  14  to another sampling station  14 ; and an ROV, which can be coupled to the interface module  17  and configured to take the picking module  16  with the fluid samples and transfer them to the analysis laboratory  19 . 
     In particular, the ROV is connected via a cable  22  to a support unit  23 , which, in turn, is connected via an umbilical cable  24  to a support boat  25 . 
     In the context of this description, the term “AUV” refers to an Autonomous Underwater Vehicle. More specifically, the term “AUV” refers to a machine that can perform underwater operations autonomously and that does not need to be connected via cable to a surface control station. 
     In addition, in the context of this description, the term “ROV” refers to a Remote Operated Vehicle. More specifically, the term “ROV” refers to a machine connected to a surface control station, via an umbilical connection cable, that can be remotely controlled by an operator to perform underwater operations of various kinds. 
     The sampling and measuring assembly  3  comprises an underwater base  26  configured to control the AUV and to store and recharge the AUV when it is not operative, and an underwater control module  27 , which occupies a predefined position in the underwater facility  2 , is configured to control, implement, and manage fluid sampling and measuring operations and is connected to the surface station  11  for transmitting signals related to the sampling and measuring operations and power transmission. 
     With reference to  FIG. 2 , the sampling and measuring module  15  comprises at least one first sensor T 1  configured to generate signals related to the measurement of the chemical-physical-thermodynamic characteristics of the fluid and/or a second sensor T 2  configured to generate a signal related to the measurement of the fluid flow rate, wherein the second sensor T 2  preferably comprises a Venturi tube or another sensor that can provide the same type of measurement or a virtual system for predicting the same measurement, such as a virtual flow meter. 
     According to a variant of this invention, not illustrated in the attached figures, the second sensor T 2  is not part of the sampling and measuring module  15  but is comprised in the underwater facility  2 . 
     The sampling and measuring module  15  is powered by the navigation module  20  and/or  21  and exchanges signals with the same navigation module  20  and/or  21 . 
     The picking module  16  comprises at least one container  28  configured to contain the fluid sample and at least one device, not illustrated in the attached figures, for transferring the fluid sample from the interface module  17  so as to keep the fluid sample under the same temperature and pressure conditions as the main fluid flow. 
     The picking module  16  is powered by the navigation module  20  and/or  21  and exchanges signals with the same navigation module  20  and/or  21 . 
     The navigation module  21  is connected via the cable  22  to the support unit  23 , which is, in turn, connected to the support boat  25  via the umbilical cable  24 , which makes it possible to transfer power and data to enable the navigation module  21  to be controlled by an operator located on the support boat  25 . 
     The interface module  17  couples the picking module  16 , the interface module  18 , and the navigation module  21  enabling power to be distributed and signals to be exchanged between the picking module  16 , the interface module  18 , and the navigation module  21 . 
     The interface module  18  couples the sampling and measuring module  15 , the interface module  17 , and the navigation module  20  enabling power to be distributed and signals to be exchanged between the sampling and measuring module  15 , the interface module  17 , and the navigation module  20 . 
     The sampling and measuring assembly  3  comprises a releasable connecting device  29  to mechanically and hydraulically connect the interface module  17  and the analysis laboratory  19  to transfer fluids from the at least one container  28  to the analysis laboratory  19 , and to exchange power and signals. 
     The analysis laboratory is powered by the navigation module  20  and/or  21  and/or exchanges signals with the same navigation module  20  and/or  21  and/or with the same underwater control module  27 . 
     The underwater base  26  is configured to exchange data and signals between the surface station  11  and the navigation module  20  to control the navigation module  20 . 
     The sampling and measuring assembly  3  comprises a permanent connecting device  30 , configured to connect the interface module  17  and the picking module  16  mechanically, hydraulically, electrically or optically, for data exchange and power transfer; a permanent connecting device  31 , configured to connect the interface module  18  and the sampling and measuring module  15  mechanically, hydraulically, electrically or optically, for data exchange and power transfer; a releasable connecting device  32 , configured to connect the interface module  17  and the navigation module  21  mechanically, electrically or optically, for data exchange and power transfer; a releasable connecting device  33 , configured to connect the interface module  18  and the navigation module  20  mechanically, electrically or optically, for data exchange and power transfer; a releasable connecting device  34 , configured to connect the interface module  18  and the sampling station  14  mechanically, hydraulically, electrically and for data exchange; and a releasable connecting device  35  configured to connect the interface modules  17  and  18  mechanically, hydraulically, electrically or optically, for data exchange and power transfer. 
     According to embodiments of this invention, not shown in the attached figures, the interface module  17  and the picking module  16  are connected so that they can be released, the interface module  18  and the sampling and measuring module  15  are connected so that they can be released, and the navigation module  20  and the interface module  18  are connected so that they can be released. 
     In the configuration in  FIG. 2 , the sampling and measuring assembly  3  comprises only one sampling and measuring module  15 , only one picking module  16 , two interface modules  17  and  18 , and two navigation modules  20  and  21  to perform sampling and measuring operations in the underwater facility  2 . 
     In particular, the navigation module  20  transports the sampling and measuring module  15  from one sampling station  14  to another sampling station  14 . The sampling only takes place when the interface module  17  is coupled to the other interface module  18 , which is coupled to the sampling station  14 . 
     At specific time intervals, the navigation module  21  takes the picking module  16  containing the containers  28  and transports it to the analysis laboratory  19  or to the surface. 
     According to an embodiment of this invention, not shown in the attached figures, each container  28  can be uncoupled from the picking module  16  and can be coupled to the analysis laboratory  19 , and can be transported individually or together to other containers  28  by the navigation module  20  or  21 . 
     With reference to  FIG. 3 , a second embodiment of the sampling and measuring assembly  36  is shown, which differs from the first embodiment in that the interface module  18 , the navigation module  20 , and the underwater base  26  are omitted. 
     In addition, the sampling and measuring assembly  36  comprises a permanent connecting device  37 , configured to connect the interface module  17  and the navigation module  21  mechanically, electrically, and for data exchange. 
     The sampling and measuring module  15  and the picking module  16  are powered by the navigation module  21  and exchange signals with the same navigation module  21 . 
     The permanent connecting device  31  and the releasable connecting device  34  are configured to connect the interface module  17  and, respectively, the sampling and measuring module  15  and the sampling station  14  mechanically, hydraulically, electrically, and for data exchange. 
     According to embodiments of this invention, not shown in the attached figures, the interface module  17  and the navigation module  21  are connected so that they can be released, and the interface module  17  and the sampling and measuring module  15  are connected so that they can be released. 
     In the configuration of  FIG. 3 , the sampling and measuring assembly  36  comprises a single sampling and measuring module  15 , a single picking module  16 , a single interface module  17 , and a single navigation module  21  to perform sampling and measuring operations in the underwater facility  2 . 
     In particular, the navigation module  21  transports the sampling and measuring module  15  and the picking module  16 , comprising the containers  28 , from a sampling station  14  to another sampling station  14  or to the analysis laboratory  19  and vice versa or to the surface. The sampling only takes place when the interface module  17  is coupled to the sampling station  14 . 
     With reference to  FIG. 4 , a sampling and measuring assembly  38  is shown in accordance with a third embodiment and which differs from the second particular embodiment in that the sampling and measuring module  15  is permanently fixed to the sampling station  14  and, therefore, the permanent connecting device  31  is omitted. 
     The releasable connecting device  34  is configured to connect the sampling and measuring module  15  and the interface module  17 . 
     The picking module  16  is powered by the underwater control module  27  and/or by the navigation module  21  and exchanges signals with the same underwater control module and/or navigation module  21 . 
     In particular, the underwater control module  27  is configured to control and/or power the sampling and measuring module  15  and the analysis laboratory  19 , and to receive data and/or signals concerning the sampling and measurements performed by the sampling and measuring module  15  and by the analysis laboratory  19 . 
     In this configuration, a sampling and measuring module  15  is required for each sampling station  14 . 
     In this configuration, just one picking module  16 , one interface module  17 , and one navigation module  21  are required to perform the sampling and measuring operations in the underwater facility  2 . 
     In the configuration of  FIG. 4 , the navigation module  21  transports the picking module  16 , comprising the containers  28 , from one sampling station  14  to another sampling station  14  or to the analysis laboratory  19  and vice versa. The sampling and measuring are also performed when the navigation module  21  is not coupled to the interface module  17 , while the fluid picking only takes place when the interface module  17  is coupled with the sampling and measuring module  15 . 
     With reference to  FIG. 5 , a sampling and measuring assembly  39  is shown in accordance with a fourth embodiment and comprises one sampling and measuring module  15  for each sampling station  14 ; one picking module  16 ; one interface module  17 ; one navigation module  21  to perform sampling and measuring operations in the underwater facility  2 ; and a releasable connecting device  32 , which is configured to mechanically connect the interface module  17  and the navigation module  21 . 
     In the particular configuration of  FIG. 5 , the navigation module  21  moves from one sampling station  14  to another sampling station  14  to pick up the picking modules with the containers  28  and transport them to the analysis laboratory  19  and vice versa. Sampling and measuring are also performed when the navigation module  21  is not coupled to the interface module  17 . 
     The sampling and measuring modules  15  are powered by the underwater control module  27  and exchange signals with the underwater control module  27 . 
     It is evident that variations can be made to this invention without departing from the scope of protection of the appended claims.