EP2834626A1

EP2834626A1 - Method for the isobaric transfer of a fluid from a deposit and device for implementing such a method

Info

Publication number: EP2834626A1
Application number: EP13714664.3A
Authority: EP
Inventors: Jean-Pierre GROLIER; Stanislaw RANDZIO; Marco Antonio AQUINO-OLIVOS
Original assignee: Universite Blaise Pascal Clermont Ferrand II; Instituto Mexicano del Petroleo; Institute Of Physical Chemistry - Polish Academy of Sciences
Current assignee: Universite Blaise Pascal Clermont Ferrand II; Instituto Mexicano del Petroleo
Priority date: 2012-04-06
Filing date: 2013-04-08
Publication date: 2015-02-11
Also published as: BR112014024830B1; FR2989167B1; MX2014011785A; US10132766B2; CA2869511C; FR2989167A1; US20150092816A1; BR112014024830A2; CA2869511A1; WO2013150158A1; PL403478A1

Abstract

The invention concerns a method for transferring a fluid under pressure from a deposit of said fluid, by means of a sampling container (5) in which a fluid sample is kept at the reservoir pressure or sampling pressure, and a method for determining at least one thermodynamic characteristic of said fluid, in particular a method for determining the phase transition envelopes. The invention also concerns a method combining the implementation of scanning transitiometry with spectroscopic or analytical techniques, optionally in the presence of a fluid in the supercritical state. The invention also concerns a device for implementing said methods.

Description

METHOD FOR THE ISOBARIC TRANSFER OF A FLUID FROM A DEPOSITION AND DEVICE

IMPLEMENTING SUCH A METHOD

DESCRIPTION

The invention relates to a method for transfer under pressure of a fluid from a reservoir of this fluid, by means of a sampling vessel (5) in which a fluid sample is maintained at the reservoir pressure (PR). ) as well as a method for determining at least one thermodynamic characteristic of this fluid, in particular a method for determining the phase transition envelopes. The reservoir fluid is advantageously crude oil.

The invention also relates to a method combining the implementation of scanning transitiometry with spectroscopic or analytical techniques, possibly in the presence of a fluid in the supercritical state. The invention also relates to a device for implementing these methods.

Hydrocarbons, in particular crude oils, include so-called asphaltene compounds which participate in the heavy fraction of the oils. These asphaltenes have variable compositions but have in common to be soluble in toluene. Asphaltenes are generally considered to precipitate in the presence of an alkane, for example in the presence of hexane, heptane or pentane. The percentage of asphaltenes in a crude oil is variable and can be up to 56% by weight of the oil.

Petroleum fluids have the particularity of precipitating under conditions of temperature and pressure that are difficult to predict. Asphaltenes are responsible for the precipitation of crude oils and thus the clogging of wells or pipes. This precipitation occurs during the variation of pressure accompanying the exit of the crude oil from the deposit to the surface and during the surface transport of the oil, even under pressure.

An understanding of the temperature and pressure from which precipitation of the asphaltenic phase occurs is important for optimizing oil extraction. Similarly, the determination of the bubble pressure, that is to say the pressure from which the first gas bubble appears under the effect of a decrease in pressure, so when the oil passes from the liquid phase in the gas phase, optimizes oil extraction. To determine these parameters, there are known standard methods defined by ASTM D.3279 and ASTM D.4124.

The titration of petroleum fluids, in particular the determination of the asphaltenes titre, may be essential, particularly for samples maintained under the live oil conditions compared to samples for which these conditions of deposit have not been maintained (dead oils in English). This titration can accurately determine the amount of asphaltenes that may precipitate.

Furthermore, patent application FR-2 771 818 discloses a method and a device for determining the thermodynamic characteristics of a polymer, for example the thermophysical properties and the phase transition envelope.

However, with such a device, the measurement is made on a sample that is introduced into a device at a pressure that is not always representative of the original pressure of the sample.

On the other hand, if for a crude oil sample, the pressure at which the measurement is made is less than or equal to the bubble pressure, at least a partial precipitation of the asphaltenes occurs. As a result, the method described by the patent application FR-2 771 818 generally does not allow reliable measurement.

Stachowiak et al. (Transitiometric asphaltenic investigation of fluids under pressure and in-well temperature conditions Energy and Fuels, Vol. 15, September ^1, 2001, pages 1033- 1037) describe a study of petroleum fluids in conditions of pressure and temperature wells deposit. However, the method described does not allow an accurate measurement of the volume of mercury displaced. The results of this method are therefore distorted.

In addition, Bessières et al. (Design Note: apparatus for simultaneous determination of the densified and heat Capacities of liquids and of liquids with Dissolved gas under an extended range of pressure (0.1-100MPa, Measurement Science and Technology, vol 1 1, May ^1, 2000, N69 pages. -N72) describe the transfer of a fluid containing a certain quantity of gas by means of a pneumatic pump in order to measure using a calorimeter.

However, it is necessary to be able to perform measurements representative of the behavior of a sample of crude oil, both within the oil reservoir and during the extraction of the sample and therefore during the variation of pressure and temperature that undergoes the oil sample during its extraction.

In order to obtain representative thermodynamic characteristics, in particular the bubble pressure and the phase transition envelopes of a crude oil sample, it is necessary to measure on a given volume of sample whose initial pressure is controlled. , or sampling pressure, as well as its sampling temperature during the entire measurement process. The thermodynamic characteristic of such a sample, whose control is essential, is usually the pressure. In order to take samples of crude oil, various containers are known, including pressure sampling bottles, also called HPB bottles, for example those used by the petroleum industry.

During measurements, these crude oil samples are put under pressure and at a temperature which can be guaranteed to reproduce accurately the initial sampling conditions.

As a result of a modification of the reservoir conditions (CR), it is possible that the sample has already undergone a modification of some of its thermodynamic characteristics or even a beginning of precipitation.

On the other hand, when inserting a given volume of sample into a measuring device, the pressure of the sample remaining in the sampling tank can be modified, which affects the subsequent measurements on that sample.

The implementation of known techniques therefore does not allow to maintain the initial pressure of the sample during its transfer between the HPB bottle and the measuring device. As a result, certain thermodynamic characteristics can not be determined representative of the behavior of oil from the deposit to the surface.

The methods and devices according to the invention make it possible to provide solutions to all or part of the problems encountered when implementing known methods and devices.

Thus, the invention provides a method that is easy to implement, fast, reliable and that makes it possible to determine the characteristics representative of the thermodynamic behavior of the asphaltenic phases of a hydrocarbon under the conditions of its extraction.

When extracted and transported to different treatment areas, hydrocarbons, especially crude oils, see the pressure and temperature they were initially subjected to change.

This development usually results in a joint decrease in pressure and temperature. In other words, the initially liquid, or even viscous or pasty, state of the crude oil is modified. Some of the components of crude oil can precipitate and disrupt the flow of oil. Precipitation can then lead to obstruction of facilities, such as wells or pipelines.

The composition of crude oil varies from one deposit to another but also from one well to another within the same deposit. Moreover, given the depths of the different wells of the same deposit, the pressures and temperatures encountered vary according to the point of sampling of the oil in a given well. The heavy fraction of the crude oils is formed in particular of aromatic molecules, grouped under the name of asphaltenes. The pressure and temperature conditions in which a phase change, solid / liquid or liquid / gas, of asphaltenes makes it possible to determine the thermodynamic characteristics of work, pressure and temperature at which extraction and transport are to be carried out. hydrocarbons. It is thus possible to keep the oil in liquid form during its extraction and then to precipitate the asphaltenic phase before transferring the oil to the petroleum processing and refining plants.

It is also important to determine the bubble pressure of crude oil, that is, the pressure at which the first vapor bubble appears when the crude oil experiences a decrease in pressure. In fact, the presence of hydrocarbon vapor in wells or pipelines disrupts the transfer of oil.

Thus, for the determination of the thermodynamic characteristics of a hydrocarbon, particularly a crude oil, it is essential to reproduce as closely as possible the initial conditions in which the hydrocarbon is found. These initial conditions designate all the conditions, for example the temperature and the pressure, encountered at the level of the extraction zone.

These initial conditions, known as reservoir conditions (CR), must be known before being able to determine the evolution of certain thermodynamic characteristics of asphaltenic crude oils.

For this purpose, the invention provides a method of transfer under pressure of a fluid from a reservoir of this fluid, by means of a sampling vessel (5) in which the sample is maintained at the pressure of reservoir (PR), or sampling pressure, and which comprises the steps of: a) measuring, in the absence of contact with the sample, the pressure of the sample maintained at its reservoir pressure (PR) in the container of sampling (5); b) connecting the sampling container (5), held closed and at the reservoir pressure, to a measuring device; c) filling the entire measuring device with a second liquid fluid, neutral to the sample, of known density and greater than that of the reservoir fluid; d) increasing the pressure in the measuring device and the pressure of the second neutral liquid fluid contained therein to a pressure equal to that of the reservoir fluid sample determined in step (a); e) increasing the pressure of the reservoir fluid sample contained in the sampling vessel (5) to a pressure greater than that of the second neutral liquid fluid contained in the measuring device; f) simultaneously transferring all or part of the reservoir fluid sample from the sampling vessel (5) to a measuring cell (2) by balancing the pressures of the sampling vessel (5) and the cell measuring (2); and an equivalent volume of the second neutral liquid fluid, from the measuring cell (2) to the sampling container (5); (g) after disconnecting the sampling vessel (5), measuring the mass of the second fluid volume, neutral, transferred to the sampling vessel (5), at constant pressure and in the absence of contact with the reservoir fluid sample; h) calculate the reservoir fluid sample volume displaced and introduced into the measuring cell.

Advantageously, the transfer method according to the invention relates to a reservoir fluid which is crude oil comprising an asphaltenic phase.

The transfer method according to the invention can be implemented for the transfer of any type of hydrocarbon containing in particular also waxes, resins or gas.

Also advantageously, during the implementation of the transfer method according to the invention, in particular during one or the other of the steps (a) to (h), the reservoir fluid sample present in the sampling vessel (5) or in the measuring cell (2) is heated and maintained at its reservoir temperature.

Preferably, during step (e) of the transfer method according to the invention, the pressure of the reservoir fluid sample contained in the sampling vessel (5) is increased to a higher pressure of 5 MPa at 7 MPa to that of the second neutral liquid fluid contained in the measuring device. Also preferably, during the implementation of the transfer method according to the invention, in particular during step (e), the reservoir fluid sample is maintained at a pressure greater than or equal to the pressure bubble of this fluid.

Also preferably, the transfer method according to the invention comprises heating the reservoir fluid sample in the sampling vessel (5) or in the measuring cell (2) at the reservoir temperature (TR). of the deposit.

Before step (e) or before step (d) and during a preliminary step, the measuring cell is heated and maintained at the reservoir temperature of the fluid sample which is the sampling temperature of the sample. 'sample.

Particularly advantageously, the transfer method according to the invention allows the fluid to be held at the reservoir pressure in the sampling vessel (5) after having disconnected the latter from the measuring device. It is then possible to carry out other measurements.

Prior to the implementation of the transfer method according to the invention, the stability of the maintenance of the pressure in the measuring device can advantageously be verified, for example by injecting nitrogen in order to check the absence of leakage.

The transfer method according to the invention also advantageously makes it possible to maintain the initial pressure of a fluid sample constant in order to determine its thermodynamic characteristics, taking into account the volume of this fluid sample.

Thus, the invention provides a method for determining at least one thermodynamic characteristic of a fluid from a reservoir of this fluid comprising the transfer of a sample of reservoir fluid according to the transfer method of the invention followed. of step (i) of determining at least one thermodynamic characteristic of the deposit fluid by means of a measuring cell (2) adapted to perform the determination of at least one such thermodynamic characteristic.

The method for determining at least one thermodynamic characteristic according to the invention therefore comprises the steps of: a) measuring, in the absence of contact with the sample, the pressure of the sample maintained at its reservoir pressure (PR) in the sampling container (5); b) connecting the sampling container (5), held closed and at the reservoir pressure, to a measuring device; c) filling the entire measuring device with a second liquid fluid, neutral to the sample, of known density and greater than that of the reservoir fluid; d) increasing the pressure in the measuring device and the pressure of the second neutral liquid fluid contained therein to a pressure equal to that of the reservoir fluid sample determined in step (a); e) increasing the pressure of the reservoir fluid sample contained in the sampling vessel (5) to a pressure greater than that of the second neutral liquid fluid contained in the measuring device; f) simultaneously transferring all or part of the reservoir fluid sample from the sampling vessel (5) to a measuring cell (2) by balancing the pressures of the sampling vessel (5) and the cell measuring (2); and an equivalent volume of the second neutral liquid fluid, from the measuring cell (2) to the sampling container (5); (g) after disconnecting the sampling vessel (5), measuring the mass of the second fluid volume, neutral, transferred to the sampling vessel (5), at constant pressure and in the absence of contact with the reservoir fluid sample; h) calculating the reservoir fluid sample volume displaced and introduced into the measuring cell;

(i) determining at least one thermodynamic characteristic of the reservoir fluid by means of a measuring cell (2) adapted to perform the determination of at least one such thermodynamic characteristic. The advantageous or preferred characteristics of the transfer method according to the invention also define the advantageous or preferred characteristics of the method for determining at least one thermodynamic characteristic according to the invention.

Advantageously, the determination method according to the invention can be implemented to determine at least one thermodynamic characteristic chosen from a thermophysical characteristic or a thermomechanical characteristic, a phase transition envelope, bubble pressure, titration, compressibility, thermal expansion.

During the implementation of the determination method according to the invention, it is possible to determine a thermodynamic characteristic by variation of a first parameter chosen from the pressure (P), the temperature (T) or the volume (V). , depending on a second parameter, while keeping the third parameter constant.

Advantageously, the method for determining at least one thermodynamic characteristic according to the invention makes it possible to determine, separately or simultaneously, the phase transition envelope or the bubble pressure of the asphaltenic phase of a crude oil.

The method for determining a thermodynamic characteristic according to the invention makes it possible in particular to determine the precipitation conditions of the asphaltenes of a crude oil sample, as a function of the pressure and the temperature. This method also makes it possible to determine the evolution of the bubble pressure.

It is therefore possible to represent, for a particular crude oil sample, the evolution of the pressure according to the temperature while keeping the volume of the sample constant; reservoir conditions (CR) having been measured beforehand.

It is then possible to determine a high value (PH) and a low value (PB) of the pressure, as a function of the temperature, and which correspond to pressures at which precipitation of asphaltenes is possible. These values (PH) and (PB) of the pressure define the phase envelope of the asphaltenes of the test oil sample.

It is also possible to determine the value of the bubble pressure (B) of the crude oil sample.

The transfer method according to the invention or the determination method according to the invention can also implement one or more elements chosen from probes, optical fibers or other means of connecting spectroscopic or analytical measurement detectors such as infrared spectroscopy, ultraviolet spectroscopy or mass spectroscopy detectors. These additional elements can be combined with miniature capillaries or micro-capillaries for the injection of at least one fluid, for example the injection of an alkane (especially pentane, hexane or heptane), or the injection of at least one fluid in the supercritical state, for example the injection of nitrogen in the supercritical state, of C0 ₂ in the supercritical state or of methane in the supercritical state.

A stirring system can also be implemented inside the measuring cell.

Such modified methods according to the invention have additional advantages, in particular they allow the determination of the thermodynamic characteristics of petroleum fluids, the determination of the threshold of precipitation / or flocculation of the heavy compounds (in particular asphaltenes, resins or waxes ), the quantification of the concentration of these heavy compounds, the determination of the precipitation or flocculation agents (in particular gases or supercritical fluids), the kinetic monitoring of the phenomena observed by a simultaneous double determination, calorimetric and spectroscopic or analytical. In addition, the use of spectroscopic or analytical analyzes gives access to the chemical nature of the species present in the transitiometric measuring cell, which is then used as a chemical reactor.

The invention thus provides methods coupling transitiometry and at least one spectroscopy or analysis technique.

During the implementation of such methods, it is possible to cause the precipitation of asphaltenes present in the petroleum fluid sample. The particles asphaltenes can then aggregate and give rise to aggregates that flocculate. This phenomenon can be initiated by adding, in particular by injection, into the petroleum fluid either an alkane (pentane, hexane or heptane), or a gas (methane, nitrogen or carbon dioxide in the supercritical state or still any other fluid in the supercritical state).

The presence of at least one optical fiber introduced into the transitiometric measuring cell makes it possible simultaneously to monitor the thermal effect due to the physico-chemical phenomena and the precipitation, as well as the changes in optical density of the light beam transmitted through the medium. . The simultaneous recording of the calorimetric signal (thermogram) and the optical signal (spectrogram) highlights the concordance of these two signals and can make it possible to show that the two effects, calorimetric and spectroscopic, are concomitant.

The methods according to the invention thus make it possible to access complete information, both quantitative and qualitative, and thermodynamic and kinetic. These methods can therefore be coupled to study experimentally the behavior of petroleum fluids whatever their nature, thus allowing to build an important database for a better knowledge of the fluids of deposits and thus the optimization of their exploitation.

The invention also relates to a device that is useful for implementing the method for transferring a fluid from a reservoir of this fluid under pressure, as well as for implementing the method for determining at least one characteristic. thermodynamics of this fluid. Thus, the invention provides a device for transferring, at the reservoir pressure (PR), a fluid sample from a reservoir of this fluid and determining at least one thermodynamic characteristic of this fluid, comprising

^■ a device for measuring a thermodynamic characteristic comprising at least one measuring cell (2), a reference cell (3), heating means and means to increase or decrease the pressure in the measuring cells (2) and reference (3);

■ a sampling container (5) removable, comprising a compression liquid and placed at a height lower than that of the measuring cell (2);

^■ a first container (R1) a liquid compression fluid and neutral vis-à-vis the reservoir fluid sample to be transferred; ^■ means for increasing the pressure in the sample container (5);

^■ a means for balancing pressures in the measuring cell (2) and into the sampling container (5);

^■ a second reservoir (R2) of liquid fluid and neutral vis-à-vis the reservoir fluid sample transferred, placed at a height greater than that of the first reservoir (R1) for compressing fluid;

^■ pipes connecting the sampling vessel (5), the tanks (R1, R2) and the measuring cell (2).

The sampling container (5) of the device according to the invention may be cylindrical in shape and have a circular base.

The device according to the invention advantageously comprises a heating means of the sampling container (5).

Advantageously, the sampling container (5) is a high pressure bottle (HPB). High pressure cylinders are used in the field of oil extraction for in situ sampling. In known manner, these high-pressure bottles can be adapted according to the specific needs of the samples. They make it possible to maintain the sample of fluid coming from a deposit at the sampling pressure or tank pressure (PR).

The device according to the invention may also comprise a sampling container (5) comprising

^■ a compartment (6) connected by a line (21) to the measuring cell (2) and able to receive the reservoir fluid sample to be transferred;

■ a compartment (7) connected by a pipe (8) to a weighing member (10) and able to receive the compression liquid.

Preferably, the sampling container (5) then comprises two compartments (6, 7) separated by a movable wall (54) in translation along the longitudinal axis (X) of the sampling container (5). More preferably, the sampling container (5) comprises a first compartment (6) provided with an outlet (51) connected by a pipe (21) to the cell of measuring (2) and a second compartment (7) provided with an outlet (50) connected by a pipe (8) to a weighing member (10).

The two compartments (6, 7) of the sampling container (5) can optionally communicate with each other in the absence of a partition wall.

Also advantageously, the device according to the invention can therefore comprise a weighing member (10), preferably a scale, connected by a line (8) only to the compartment (7) of the sampling vessel's compression liquid (5). .

The member (10) or the pipe (8) connecting it to the measuring device can be equipped with sensors (14), for example sensors for measuring pressure, temperature or other parameters.

In a particularly advantageous manner, the device according to the invention implements a neutral fluid and a compression fluid which are identical, preferably the two fluids are identical and are mercury.

Indeed, mercury is a fluid that is neutral vis-à-vis oil and is of higher density than the latter. It is therefore advantageously chosen as a neutral fluid and as a compression fluid.

Nevertheless, it is possible to use another neutral liquid fluid with equivalent characteristics, in particular with regard to its density.

The device according to the invention may also comprise a measuring cell (2) which is a transitiometer, in particular a scanning transitiometer.

It may also comprise means for titration (35) of the reservoir fluid, preferably a titration vial, as well as lines (37, 38) connecting this titration means to the measuring device.

The device according to the invention may also comprise one or more elements chosen from probes, optical fibers or other means of connecting spectroscopic or analytical measurement detectors such as infrared spectroscopy, ultraviolet spectroscopy or mass spectroscopy. These additional elements can be combined with miniature capillaries or micro-capillaries for the injection of at least one fluid, for example the injection of an alkane (especially pentane, hexane or heptane), or the injection of at least one fluid in the supercritical state, for example the injection of nitrogen in the supercritical state, of C0 ₂ in the supercritical state or of methane in the supercritical state. A stirring system can also be implemented inside the measuring cell.

The various elements of the device according to the invention, and in particular the measuring cell (2), for example a transitiometer, are made of a material resistant to high pressures and high temperatures similar to those commonly encountered in petroleum extraction. This material is neutral vis-à-vis the fluids it receives. Advantageously, it is a stainless steel.

FIG. 1 gives a schematic representation of a device according to the invention. Figure 2 gives a schematic representation of another device according to the invention.

Figure 3 represents, for a sample of crude oil, the evolution of the pressure according to the temperature while maintaining constant the volume of the sample.

The examples which follow give an illustration of various devices according to the invention as well as of the implementation of the methods according to the invention for the transfer of a fluid and for the determination of a thermodynamic characteristic of this fluid.

These examples, therefore, do not constitute a limitation of the scope of protection of the present invention, but provide an illustration and highlight of the many advantages of this invention.

Example 1: Device and method for determining phase transition envelopes and bubble pressure of asphaltenes-containing crude oil samples - Figure 1

Determination of phase transition envelopes and bubble pressure of crude oil samples containing asphaltenes can be carried out whatever gravimetric densities and colors (defined according to API - American Petroleum Institute) crude oil samples.

Samples of crude oil from a well in the Gulf of Mexico have been used without this being a limitation. The measurements were made for temperature and pressure ranges corresponding to those encountered in the original deposit of the oil sample.

The original sample well is located in the Gulf of Mexico, at a depth ranging from 80 m to 8200 m, at a pressure ranging from 8.3 MPa (1200 psi) to 55.2 MPa (8000 psi) and at a temperature ranging from 80 ° C to 170 ° C. The crude oil sample tested comprises about 0.5% by weight of asphaltenes, 6.3% by weight of resins and 60.5% by weight of saturated hydrocarbons. Its density is 0.68 and its molecular weight is 258.5.

The reservoir temperature that is the temperature in the deposit at the sampling point is 154 ° C. The reservoir pressure that is the pressure in the deposit at the sampling point is 29.7 MPa.

The measurements were carried out using measuring cells such as those described for the patent applications FR-A-2 771 818 and FR-A-2 679 650.

The determination method essentially consists in generating a transition or change of state of a compound in order to determine different thermodynamic characteristics. This change of state is effected by a controlled measurement, within defined ranges of temperatures and pressures, of the variation of a first parameter as a function of a second parameter, while keeping constant a third parameter, the three parameters. being selected from pressure, temperature or volume.

The variations of each parameter and the associated calorimetric signal are recorded and allow, after treatment, to determine the thermodynamic characteristics or derivatives of the sample.

This transitiometry method uses a scanning transitiometer broadcast by BGR TECH (Warsaw, Poland). This device makes it possible to measure at pressures ranging from 0.1 to 400 MPa, or up to 700 MPa, and this in a temperature range from 173 K to 673 K, and for sample volumes included between 0.3 and 4 ml. A data acquisition and processing module enables the processing of the thermodynamic data collected. The transitiometer comprises an insulated enclosure (1) equipped with a heating device associated with a cooling means (not shown in FIGS. 1 and 2) which makes it possible to maintain the temperature of a measuring cell (2). and a reference cell (3). Each of these cells (2, 3) is adapted to receive a particular volume of a sample or a neutral liquid fluid. The pressure and the temperature prevailing in each cell (2, 3) can be modified jointly or independently.

The reference cell (3) is filled with a neutral liquid vis-à-vis the test sample which is mercury. Mercury is a neutral liquid without chemical or physical interaction with hydrocarbons. It has a density higher than that of hydrocarbons. The mercury thus forms a neutral reference liquid which is immiscible with the sample and which can be compressed and heated.

The measuring cell (2) is adapted to receive a given volume of a crude oil sample. This volume is between 0.3 ml and 4 ml. When it contains a sample, the cell (2) can be pressurized and maintained at a certain temperature.

The cells (2, 3) have a cylindrical shape whose base is circular. One end (20) of the measuring cell (2) is connected to a circuit of pipes equipped with valves. All elements of the transitiometer, and more generally the measuring device, are made of stainless steel resistant to high pressures and temperatures similar to those commonly encountered in petroleum extraction. The material is neutral vis-à-vis the fluids it receives.

The pipes have a thickness greater than their useful diameter. As a result, these pipes are assimilated to capillary tubes. Accessories are provided on the pipe circuit connecting the different elements. These accessories are mounted fixed or removable. These include temperature sensors, pressure sensors or pumps. The sensors make it possible to collect data relating to the operation of the device and to manage the scanning transitiometer, via a data acquisition and processing module (4). The device of FIGS. 1 or 2 also comprises two reservoirs (R1, R2) intended to receive respectively a compression liquid and a neutral liquid. This is mercury for both liquids. The location of the tanks (R1, R2) is adapted to the length and configuration of the pipe circuit. The tank (R2) is disposed at a height greater than that of the tank (R1).

The sample transfer device according to the invention comprises a sampling container (5) called a high-pressure bottle or HPB which is cylindrical in shape and has a circular base. It is provided with outputs (50, 51) at each of its ends and at least one input (52) for a sensor (53), for example a temperature sensor or a pressure sensor. The bottles (5) that are used can generally contain between 250 ml and 750 ml of hydrocarbon sample. The bottle (5) used allows the sampling in a known manner of a crude oil sample. The useful volume of the bottle (5) is divided into two compartments (6, 7). This separation is performed by a movable wall (54) which is a membrane movable in translation in a direction parallel to a longitudinal axis X of the bottle (5). This wall (54) thus ensures the tight separation between the first compartment (6), defining a sample receiving volume, and the second compartment (7) defining a receiving volume of a compression fluid. The compression fluid is a synthetic oil or mercury.

The movable wall (54) can move under the effect of the pressure exerted by the sample contained in the compartment (6) until the pressures of the two compartments (6, 7) are balanced and the fluid compression contained in the compartment (7) is at the same pressure as the sample in the compartment (6).

The compartments (6, 7) are partially delimited by the ends of the bottle (5) provided with outlets respectively 51, 50).

When the outlet (50) is open, the displacement of the movable wall (54) induces a displacement of the compression fluid out of the bottle (5).

When the outlet (50) is closed, the displacement of the movable wall (54) induces compression of the compression fluid.

By means of a pressure sensor (53) placed at the compartment (7), it is possible to measure the pressure of the compression fluid which is identical to the pressure of the sample.

It is therefore possible to determine the initial pressure of the sample, without modifying it and in the absence of direct contact with the sample. A line (8) provided with at least one valve (9) connects the bottle (5), from the compartment (7) for receiving the compression fluid, to a weighing member (10).

The weighing member (10) comprises a balance, known per se, having an accuracy of the order of 0.1 mg. This scale makes it possible to measure the mass of the compression fluid in a weighing container suitable for weighing a liquid. This scale is in a closed enclosure, provided with valves (1 1, 12, 13) which make it possible to control the displacement of the compression liquid from the compartment (7) of the bottle (5) towards the weighing member (10) . Thus, the weighing member (10) can be isolated from the bottle (5). It is therefore also possible to allow the circulation of the compression liquid between these two elements. This circulation can be assisted by a pump.

Alternatively, the bottle (5) can be disconnected from the measuring device to allow the compression liquid to be weighed.

The enclosure in which the weighing member (10) is located makes it possible to heat up and maintain the temperature of the weighing member (10) as well as the compression liquid present in this weighing member ( 10), without contact with the compression liquid and maintaining the pressure of the compression liquid. As a result, the pressure of the compression liquid does not vary between the compartment (7) of the bottle (5) and the weighing member (10).

The bottle (5) is arranged to prevent the gravity displacement of the sample from the bottle (5) to the measuring cell (2) when the valves are open and the entire measuring device is at a minimum. same pressure. Preferably, the bottle (5) is positioned at a height lower than that of the measuring cell (2), in particular at a height less than that of the transitiometer.

Since the weighing member (10) is not connected to the compartment (6) of the bottle (5) containing the sample, the opening of the valves (9, 1 1, 12, 13) generates a balancing pressures of the sample and the compression liquid respectively present in the compartments (6) for the sample and in the compartment (7) and in the weighing member (10) for the compression liquid. The member (10) is equipped with sensors (14), for example pressure sensors, temperature sensors or other parameters.

From the outlet (51) of the compartment (6) of the sample, the bottle (5) is also connected to a measuring cell (2) which is a scanning transitiometer. Valves (15, 16, 17, 18, 19) arranged on the pipe (21) make it possible to make a connection by ensuring that there is no communication between the inside of the bottle (5) and the the inside of the transitiometer (2), when at least one of these valves (15, 16, 17, 18, 19) is closed.

The remainder of the measuring device circuit comprises an expansion chamber (22) connected to the measuring cell (2) by means of lines (21, 23) and to a reservoir (R1) of neutral liquid via a pipe (24) as well as a tank (R2) by another pipe (25).

Thus, the chamber (22) makes it possible to regulate the flow rates and pressures of the liquids circulating in the various pipes (21, 23, 24, 25) of the circuit.

The pipe (24) is provided with at least two valves (26, 27) disposed on either side of a pump (28) and near the tank (R1). The pump (28) and a pressure sensor (29) are connected to the module (4).

The conduit (25) also includes valves (30, 31, 32, 33). A valve (31) is provided with a free outlet for withdrawing liquid present in the pipe (25), while two valves (30, 32) are located on either side of the valve (31) and near the tank (R2).

The three-way valve (33) is connected to the end of the pipe (23) and close to the measuring cell (2). From the tank (R2), the three-way valve (33) is used to inject neutral liquid directly into the circuit, independently of the chamber (22). The three-way valve (33) can also be used to isolate the measuring cell (2).

A sensor (34) connected to the module (4) is present on the pipe (23), between the valve (33) and the end (20) of the measuring cell (2). The devices which are represented by FIGS. 1 and 2 have a movable wall (54) but in an alternative embodiment (not shown), when the chosen compression liquid is identical to the neutral liquid, for example mercury, neutral and not miscible with the crude oil, the bottle (5) may be free of movable wall (54) or movable membrane. Therefore, the physical separation between the two compartments (6, 7) can be avoided. Such a configuration facilitates the construction of the bottle (5) used and can improve the accuracy of the pressure measurement.

The device according to the invention is implemented according to the transfer method of the sample of the invention, from the bottle (5) to the measuring cell (2).

In a first step, the bottle (5) is connected to the measuring cell (2) and to the weighing member (10) at the valves (15, 16) located on the pipe (21) and at the level of the valve (9) located at the end of the pipe (8). The connection via the pipe (21) is removable (not shown) which makes it possible to connect the sampling vessel (5) to another measuring device, in particular to a known device for measuring the thermodynamic characteristics of a hydrocarbon, for example example on a known transitiometer.

In another step, the scale of the weighing member (10) is calibrated by opening the valves (9) and (12) in order to weigh the compression fluid which is at the same pressure as the crude oil sample. By weighing the compression fluid, of known density and controlling its pressure, it is possible to determine if the initial conditions or reservoir conditions (CR), and therefore of measurement, are close to the bubble pressure. If necessary, it is avoided to use the sample whose pressure is close to the bubble pressure.

The comparison of the sample pressure under reservoir conditions (CR) and bubble pressure is performed from measurements made previously or from bibliographic data. In a next step, the bottle (5) is heated to a measurement temperature which is advantageously the tank temperature (TR). This is the temperature at which the crude oil sample was collected.

The heating is carried out by means known as such. Once the tank temperature (TR) has been reached, the bottle (5) is maintained in temperature in a heat-insulated enclosure (not shown) in a manner similar to maintaining the temperature of the transitiometer.

During this heating, the initial pressure of the sample in the bottle (5) is also kept constant by means of the valve (9) making it possible to control the outlet of the compression fluid, and therefore of the mercury, out of the compartment (7) of the bottle (5).

Since the bottle (5) is connected but without possibility of circulation of the sample between the bottle (5) and the transitiometer, the temperature sample is kept isolated from the scanning transitiometer. Then, the neutral liquid, mercury, contained in the tank (R2), is at least introduced into the pipe (25) by opening the valve (30) or advantageously in the other pipes (21, 24) also opening the other valves.

When filling the circuit with mercury, take care to evacuate the residual air present in the circuit. Mercury, possibly collected, during the evacuation of air, for example at the valve (31), is collected in a container (not shown) adapted for reuse.

Once the circuit filled with mercury, the valve (30) is closed. The stability of the pressure is checked.

One can also check the absence of leaks in the circuit before it is filled by injecting nitrogen into the circuit via the valve (31). In this case, the valve (30) at the outlet of the tank (R2) is closed during the injection of nitrogen to prevent any mercury projection out of the tank (R2). The entire circuit is pressurized with nitrogen for a given time, for example 30 minutes. Once this verification has been carried out, the valve (31) is closed and the residual nitrogen is evacuated, for example by a discharge valve 19. Once the evacuation of the nitrogen carried out, the nitrogen tank is disconnected from the valve (31) and replaced by a vacuum pump (not shown) which, for at least fifteen minutes, provides the vacuum of the whole circuit. During this evacuation step, it should also be checked that there is no leak in the circuit. For this, the pressure is constantly monitored. After this evacuation, the valve (31) is closed and the vacuum pump is disconnected from the circuit. The entire measuring device, namely the scanning transitiometer, and the different lines, is thus maintained under a vacuum close to 0.13 MPa.

In a next step, the valve (30) is gradually opened to transfer mercury from the reservoir (R2) in the circuit to equilibrium when the circuit is filled with mercury. The filling is advantageously performed by gravity, using the difference in height between the circuit and the reservoir (R2) of mercury. For this, the reservoir (R2) of mercury must be permanently filled. Alternatively, it is possible to use a pump (not shown) in this step.

When the mercury in the circuit is at equilibrium at any point of the circuit, it is advisable to close all the valves

Pressure is then applied when the system is filled with mercury. The valve (26) is opened for this purpose and the pump (28) connected to the other mercury reservoir (R1) is then programmed to increase the pressure of the mercury in the device to the study pressure which is the pressure. of the sample contained in the bottle (5) and which corresponds to its original pressure or tank pressure (PR).

In other words, a tank (R2) of mercury is used to saturate the neutral liquid circuit and another tank (R1) ensures the pressurization of the neutral liquid by a compression liquid.

In the alternative case where the neutral liquid and the compression liquid are the same and are mercury, it is possible to use a single mercury reservoir. The pipes and the circuit are then adapted to this particular configuration. Nevertheless, the presence of two tanks (R1, R2) facilitates the handling of mercury and improves safety.

Once the study pressure is reached, the valves (30) and (32) are open. The safety valve (16) on the pipe (21) connecting the bottle (5) to the transitiometer (2) is also open.

At this stage, preferably, the pressure is kept constant in all the pipes in communication for at least 30 minutes in order to confirm the total absence of micro-leaks as well as to ensure that the pressure is easily maintained.

The pump (28) for pressurizing the circuit is a pump reversibly mounted between the valves (26) and (27) in order to keep the pressure prevailing in the circuit constant during the heating thereof. This pump (28) thus makes it possible to increase or reduce the pressure.

In a next step, the transitiometer (2) and the different lines are heated to the measurement temperature which is the temperature of the bottle (5) or tank temperature (TR).

Once this step has been completed and the pump (28) stopped, all the elements of the scanning transitiometer and the bottle (5) are at barometric and thermal equilibrium.

Then, the oil contained in the compartment (6) of the sampling bottle (5) is brought to a pressure greater than its initial pressure (PR). The pressure inside the compartment (6) is thus increased in order to obtain a pressure difference permitting the transfer of the sample from the bottle (5) to the transitiometer (2) and making it possible to avoid any risk of precipitation. during the transfer, avoiding to get closer to the bubble pressure of the oil sample studied. During this step, the pressure is then increased from 5 MPa to 7 MPa relative to its initial pressure, a preferred pressure increase being close to 5 MPa. The pressure increase is carried out by means of a pump (not shown) which is connected to the weighing member (10). This pump, by compressing the compression liquid, and therefore the mercury contained in the compartment (7) of the bottle (5), compresses the sample contained in the compartment (6) due to the displacement of the compression liquid in the direction of this compartment (6).

In a next step, once the overpressure of the sample has been achieved, the valve (15) is opened. Due to the depression created, the sample is moved from the bottle (5) to the measuring cell (2). The valves (15), (16), (18), (19) being open, because the lines of the circuit, in particular the pipe (21), connecting the bottle (5) to the measuring cell (2) are capillaries and that the bottle (5) is at a height less than the height of the measuring cell (2), there is a gravity displacement of the mercury column from the cell (2) to the bottle (5). ). Simultaneously, the oil sample moves from the bottle (5) to the measuring cell (2).

The sample then occupies a volume of the measuring cell (2) identical to the volume of mercury.

In the absence of a movable wall (54) in the bottle (5) and because of its higher density, the mercury moves by gravity directly from the compartment (6) to the compartment (7) containing mercury as a compression liquid.

Alternatively, when the bottle (5) comprises a movable wall (54), the mercury is deposited on this wall in the compartment (6), without mixing with oil.

At equilibrium in the measuring cell (2), the oil sample is at the measuring pressure (PR) which is the initial pressure at which it was in the bottle (5).

The volume of crude oil introduced into the measuring cell (2) when opening the valves (15) to (19) corresponds to the volume of mercury displaced from the measuring cell (2) in the bottle (5).

Once the sample has been transferred, the bottle (5) is isolated by closing the valves (15) and (16). After returning to equilibrium, the volume of oil displaced after weighing the amount of mercury displaced by means of the weighing member (10) is determined. The initial pressure of the liquid present in the bottle (5) and the initial volume of this bottle (5) were not modified during the transfer of the sample. Thus, the difference in mass corresponds to the volume of mercury having replaced the volume of oil sample in the bottle (5).

Thus, from the mass of the amount of mercury introduced into the bottle (5) and knowing the density of the mercury, it is possible to calculate the volume of mercury initially present in the measuring cell (2) which has been moved in the bottle (5). The identical volume of oil displaced from the bottle (5) is then known and introduced into the measuring cell (2).

This determination of the sample volume introduced into the transitiometer (2) is therefore performed independently of the initial volume of the sample in the bottle (5) while maintaining the pressure (PR). This determination can be easily repeated until the bottle (5) no longer contains oil.

During measurements in the transitiometer (2), the bottle (5) is isolated from the measuring circuit by closing the valves. Advantageously, the bottle (5) is maintained in temperature and slight overpressure in order to facilitate sample transfers during subsequent measurements.

Once the measurements have been made, the heating of the bottle (5) is stopped and allowed to cool while compensating for the pressure drop, for example by means of a pump, for example a pump associated with the weighing member ( 10). This keeps the bottle (5) at its original pressure until it is at room temperature. Once the ambient temperature is reached, the bottle (5) is isolated and disconnected from the circuit by closing the valves (9), (15), (16).

Once the measurements are completed, the transitiometer is cooled and brought back to atmospheric pressure, the oil and mercury present in the circuit are collected, for example by emptying at the valve (31). Example 2 Device and Method for Asphaltene Titration of Crude Oil Samples - Figure 2

In this second embodiment, the titration of the crude oil sample with an organic solvent is also determined. The titration method is known as such.

For this second embodiment, the sample transfer device is similar to the device of example 1 and the transfer of a known volume of sample is carried out according to the method of this example 1.

Determining new parameters involves mounting on the circuit of a titration vial (35) between the valve (19) and a valve (36) located on the conduit (25). The valve (19) is then not a discharge valve.

The geometry of the pipe (25) is different and requires a different configuration of the tank (R2) and the valves (30), (31), (33).

The bulb (35) is connected to the chamber (22) and to the pipe (25) which is provided with a three-way valve (36) by means of a pipe (37) also provided with a valve (38). ).

The bulb (35) behaves similarly to the transitiometer of Example 1; the sample transfer steps are identical to those described for Example 1. In particular, the steps of heating the bottle (5) or filling the circuit with mercury contained in the tank (R2). The entire circuit is also subjected to a pressurization test by bringing the portion containing the titration fluid to the study pressure, similarly to the first embodiment, by closing or opening valves.

After having evacuated the circuit and before filling it with mercury, the titration liquid is loaded into the titration vial (35) while it is isolated from the circuit by prior closing of the valves (19) and (38). ).

Then, the valve (38) is opened to communicate the titration vial (35) and the mercury filled circuit.

The titration liquid is fed to the measuring pressure or tank pressure (PR). After carrying out a pressure stability test to check the absence of leakage, the transitiometer is, in a manner similar to Example 1, put under the conditions of temperature and pressure for the measurement.

Using a titration method known per se, using n-heptane, at the temperature and pressure conditions, complementary thermodynamic characteristics are obtained which, together with the data relating to the phase envelopes and to the pressure of bubble, to reliably describe the thermodynamic behavior of the hydrocarbon during its extraction and its treatment. In this titration method, an amount of alkane is added to the asphaltenic crude oil sample, which then precipitates the asphaltenes which are separated by filtration and then weighed, thus making it possible to determine the asphaltene concentration in the crude oil sample. .

Knowledge of the sample volume, pressure and reservoir temperature allows the determination of thermodynamic variables. Indeed, the three variables V, P, T being known, it is possible to maintain a constant variable and follow the evolution of a second variable according to a third variable. In this way, the following thermodynamic derivatives can be obtained: dP / dV, dV / dP, dT / dV, dT / dP.

Claims

A method of transfer under pressure of a fluid from a reservoir of this fluid, by means of a sampling vessel (5) in which the sample is maintained at the reservoir pressure (PR) and which comprises the steps of: a) measuring, in the absence of contact with the sample, the pressure of the sample maintained at its reservoir pressure (PR) in the sampling vessel (5); b) connecting the sampling container (5), held closed and at the reservoir pressure, to a measuring device; c) filling the entire measuring device with a second liquid fluid, neutral to the sample, of known density and greater than that of the reservoir fluid; d) increasing the pressure in the measuring device and the pressure of the second neutral liquid fluid contained therein to a pressure equal to that of the reservoir fluid sample determined in step (a); e) increasing the pressure of the reservoir fluid sample contained in the sampling vessel (5) to a pressure greater than that of the second neutral liquid fluid contained in the measuring device; f) simultaneously transferring all or part of the reservoir fluid sample from the sampling vessel (5) to a measuring cell (2) by balancing the pressures of the sampling vessel (5) and the cell measuring (2); and an equivalent volume of the second neutral liquid fluid, from the measuring cell (2) to the sampling container (5); (g) after disconnecting the sampling vessel (5), measuring the mass of the second fluid volume, neutral, transferred to the sampling vessel (5), at constant pressure and in the absence of contact with the reservoir fluid sample; h) calculate the reservoir fluid sample volume displaced and introduced into the measuring cell.

2. Method according to claim 1 for which the reservoir fluid is crude oil comprising an asphaltenic phase.

The method of claims 1 or 2 including the step of (e) increasing the pressure of the reservoir fluid sample contained in the sampling vessel.

(5) to a pressure greater than 5 MPa at 7 MPa than that of the second neutral liquid fluid contained in the measuring device.

The method of claims 1 to 3 comprising heating the reservoir fluid sample in the sampling vessel (5) or in the measuring cell (2) to the reservoir temperature (TR) of the reservoir.

5. A method for determining at least one thermodynamic characteristic of a fluid from a reservoir of this fluid comprising the transfer of a reservoir fluid sample according to claims 1 to 4 and the step of (i) determining at least one thermodynamic characteristic of the reservoir fluid by means of a measuring cell (2) adapted to perform the determination of at least one such thermodynamic characteristic.

6. Method according to claim 5 for determining at least one thermodynamic characteristic selected from a thermophysical characteristic or a thermomechanical characteristic, a phase transition envelope, bubble pressure, titration, compressibility, thermal expansion.

7. Method according to claim 5 or 6 in which the thermodynamic characteristic is determined by variation of a first parameter selected from the pressure (P), the temperature (T) or the volume (V), as a function of a second parameter, while keeping the third parameter constant.

8. Method according to claims 1 to 7 also comprising the implementation ^■ of one or more elements selected from the probes, optical fibers or other means to connect detectors spectroscopic or analytical measurements and one or more of these detectors such as infrared spectroscopy detectors, spectroscopy ultra- violet or mass spectroscopy; or

^■ miniature capillaries or micro-capillaries, and injecting at least one fluid, for example the injection of an alkane (such as pentane, hexane or heptane), or injecting at least one fluid to supercritical state, for example supercritical nitrogen injection, supercritical CO ₂ or supercritical methane; or

^■ a stirring system inside the measuring cell.

9. A device for transferring, at the reservoir pressure (PR), a fluid sample from a reservoir of this fluid, comprising a device for measuring a thermodynamic characteristic comprising at least one measuring cell (2). ), a reference cell (3), heating means and means for increasing or decreasing the pressure in the measuring (2) and reference (3) cells;

^■ a sampling container (5) removable, comprising a compression liquid and placed at a height lower than that of the measuring cell (2);

^■ a first container (R1) a liquid compression fluid and neutral vis-à-vis the reservoir fluid sample to be transferred;

^■ means for increasing the pressure in the sample container (5);

10. Device according to claim 9 also comprising a heating means of the sampling container (5).

1 1. Device according to claims 9 or 10, the sampling container (5) comprises

^■ a compartment (7) connected by a pipe (8) to a weighing member (10) and able to receive the compression liquid.

12. Device according to claim 1 1, the sampling container (5) comprises two compartments (6, 7) separated by a movable wall (54) in translation along the longitudinal axis (X) of the sampling container (5). ).

13. Device according to claims 9 to 12, the sampling container (5) comprises a first compartment (6) provided with an outlet (51) connected by a pipe (21) to the measuring cell (2) and a second compartment (7) provided with an outlet (50) connected by a pipe (8) to a weighing member (10).

14. Device according to claim 13, the weighing member (10) is connected by a pipe (8) only to the compartment (7) of the compression liquid of the sampling container (5).

15. Device according to claims 9 to 14, the neutral fluid and the compression fluid are identical.

16. Device according to claim 15, the neutral fluid and the compression fluid are identical and are mercury.

17. Device according to claims 9 to 16, the measuring cell (2) is a transitiometer.

18. Device according to claims 9 to 17 also comprising

^■ a titration means (35) of the reservoir fluid;

^■ lines (37, 38) connecting this titration means to the measuring device.

19. Device according to claim 18, the titration means of which is a titration vial.

Apparatus according to claims 9 to 19 also comprising one or more elements selected from probes, optical fibers or other means for connecting spectroscopic or analytical measuring detectors and one or more of such detectors such as detectors. infrared spectroscopy, ultraviolet spectroscopy or mass spectroscopy; or miniature capillaries or micro-capillaries for injecting at least one fluid, for example the injection of an alkane (in particular pentane, hexane or heptane), or the injection of at least one fluid with the supercritical state, for example the injection of nitrogen in the supercritical state, of C0 ₂ in the supercritical state or of methane in the supercritical state; or a stirring system inside the measuring cell.