Method and device to analyse fluid

The present invention relates to a technology evaluation subterranean formation using a downhole tool disposed in a wellbore penetrating a subterranean formation. More particularly, but not by way of limitation, the present invention relates to techniques of measuring formation fluids.

Wells are drilled to locate and produce hydrocarbons. A downhole drilling tool with a drill bit on its end deeper into the earth to form the wellbore. With the deepening of the drilling tool drilling fluid pumped through the drilling tool and out of the drill bit to cool the drilling bit and to remove cuttings. The drilling fluid forms a filter cake additionally that covers the wellbore.

During drilling operations it is desirable to perform various evaluations of the formation penetrated by the wellbore. In some cases, the drilling tool must be removed, and the tool can be lowered into the wellbore on a wireline testing and / or sampling of the formation. In other cases, the drilling tool may be provided with a device for testing and / or sampling the surrounding formation and the drilling tool may be used to perform testing or sampling. The samples or tests may be used, for example, to determine the location of useful hydrocarbons.

Formation evaluation often requires that fluid from the formation has been recovered at the downhole tool for testing and / or sampling. Various devices, such as probes is shifted out of the downhole tool to establish fluid interaction with the formation surrounding the wellbore and to draw fluid into the downhole tool. A typical probe is a cylindrical member extended from the downhole tool and positioned opposite the sidewall of the wellbore. A rubber seal on the end of the probe is used to create a seal with the wellbore wall. Another device used to form a seal with the wellbore, called a double seal. With the use of dual-seal, two elastomeric rings strung on a tool to isolate the portion of the wellbore between them. The rings form a seal with the wellbore wall and permit fluid to enter into the isolated portion of the wellbore and into an inlet in the downhole tool.

The filter cake covering wellbore often assists the probe and / or dual sealant in creating a seal with the wellbore wall. When the seal is made, fluid from the formation into the downhole tool is retrieved through the inlet due to pressure reduction in the downhole tool. Examples of probes and / or sealants used in downhole tools are described in U.S. Patent №№6301959; 4860581; 4936139; 6585045; 6609568 and 6719049 and US Patent №2004 / 0000433.

Evaluation is generally performed on the formation fluid that is extracted into the downhole tool. Currently, the technology exists perform various measurements preliminary testing and / or sampling the fluid which enters into the downhole tool.

Fluid passing through the downhole tool can be tested to determine various downhole parameters or properties. Various properties of the hydrocarbon fluid reservoir, such as viscosity, density and phase behavior of fluid in a reservoir can be used to assess potential reserves determine flow through porous media and mechanical design systems complete, separation, processing and measurement of, among other things.

Further, the fluid sample can be collected in the downhole tool and retrieved to the surface. The downhole tool keeps fluids in the formation of one or more sample chambers or bottles for samples and extracts the bottles from the surface of the formation fluid, under pressure. An example of this type of sampling is described in U.S. Patent №6688390. These tests are sometimes called living fluids. These fluids may then be shipped to a suitable laboratory for further analysis. Normal analysis or determining fluid parameters may include, for example, composition analysis, fluid properties and phase behavior. In some cases, this assay can also be performed on the surface of the well using a mobile laboratory c system. Technologies have been developed to perform a live test fluid on the surface. Many of the measurements of the fluid may require time about an hour or more. For example, in the analysis or detection of fluid phase behavior starts from one state, liquid or gas. The temperature is kept constant. The volume is increased by a series of small steps. Before performing the next step to change the volume of the pressure should be stable. To reduce the time required to stabilize the pressure fluid is stirred vigorously. Such mixing typically comprises mixing, stirring, shearing, vibration, and / or other movement of the fluid volume. During process steps or increase in optical technology used to determine the presence of separate phases. For example, the high-pressure chamber with a 2-micron resolution can be used to obtain images through an optical window, and can be made by measuring the absorption of light by using the near infrared spectrum.

During sampling the fluid reservoir may exhibit a plurality of phase transitions. Often, these transitions are the result of cooling, the pressure drop and / or composition changes that occur when the fluid is recovered in the product and / or retrieved to the surface. Determination of fluid phase behavior is key in planning and optimization of field development and production. Changes in temperature (T) and pressure (P) of the formation fluid often entails multiphase separation (e.g., liquid-vapor, liquid-solid, liquid-liquid, liquid-vapor, etc.) and recombination phases. Similarly, single-phase gas generally has an envelope, which separates the liquid phase, known as the condensation point. These changes may prevent measurement, which takes place during the formation evaluation. Moreover, there is a significant time lag between sampling and testing on the surface or in third-party laboratories.

Therefore, it is desirable to create technology capable of performing an assessment of the formation fluid. Additionally, it is desirable that such technology provides accurate measurements in real time. Such evaluation may be required for the formation operation at the time constraints of size and operations in the wellbore and preferably performed in the well. Such a device for the analysis of fluid that can carry out such an assessment formations created by the present invention.

In at least one aspect, the present invention relates to an apparatus for analyzing the fluid. The apparatus includes a test chamber is adapted to move the fluid discharge node and at least one sensor. The test chamber forms a cavity for receiving the estimated fluid. The device for moving fluid a force means a force is applied to the fluid, causing the fluid to move within the cavity. Pressure unit continuously changes the fluid pressure. At least one sensor cooperates with the fluid to determine at least one parameter of the fluid during the continuous change of pressure fluid.

In one embodiment, the test chamber is formed as a channel, such as a recirculation loop. In another embodiment, the test chamber includes a channel, a bypass loop communicating with the duct and defining an evaluation chamber and at least one valve located between the duct and the estimated cavity bypass loop for selectively removing fluid into the evaluation cavity bypass loop from the channel.

In yet another embodiment, a device for moving fluid comprises a pump. Optionally, the means for moving fluid comprises an agitating member disposed in the cavity and generating the estimated in the fluid swirl. In this embodiment, at least one sensor located inside the vortex is desirable.

In yet another embodiment, a device for moving fluid and a delivery unit are integrally formed, and together comprise a first body, a second body, the first piston and the second piston. The first housing defines a first chamber communicating with the cavity in the evaluation of the test chamber. The second housing defines a second cavity communicating with the cavity in the evaluation of the test chamber. The first cavity has a cross sectional area greater than the cross-sectional area of ​​the second cavity. A first piston disposed within the first cavity and is movable in the first cavity. The second piston is located within the second lumen and is movable within the second lumen. Moving the first and second pistons are synchronized for simultaneous movement of fluid and pressure changes in the test chamber.

In the embodiment designed for detecting changes of phases of the fluid, at least one detector desirably includes a pressure sensor, a temperature sensor boiling point. The pressure sensor reads the pressure within the evaluation cavity in the test chamber. The temperature sensor reads the temperature of the fluid within the evaluation cavity in the test chamber. Boiling point sensor detects the formation of bubbles within the fluid.

In another aspect, the present invention relates to a downhole tool located in a wellbore having a wall and held in a subterranean formation. Formation contains a fluid. The downhole tool includes a housing adapted for connection to the fluid and apparatus for analyzing fluid. Device for communication with a fluid capable of advancing from the body to provide intimate contact with the borehole wall. Device for communication with the fluid comprises at least one inlet for receiving fluid from the formation. Device for analyzing a fluid is disposed within the housing. The apparatus includes a test chamber, a device for moving fluid discharge node and at least one sensor. Test chamber forms a cavity for receiving the estimated fluid from the device to communicate with the fluid. The device for moving fluid a force means a force is applied to the fluid, causing the fluid to move within the cavity. The discharge unit changes the pressure of the fluid. At least one sensor cooperates with the fluid to determine at least one parameter of the fluid. Apparatus for analyzing fluid may be any of the above described embodiments.

In one embodiment, the device for communication with the fluid comprises at least two inlets, while one of the inlets receives clean fluid from the formation. In this embodiment, the downhole tool further comprises a channel receiving the clean fluid from one of the inlets device for communication with the fluid and delivers clean fluid to the estimated cavity.

The present invention also relates to a method for measuring an unknown parameter of the fluid within the wellbore extending into the formation containing fluid. In this method, a device for fluid communication with a downhole tool disposed in tight contact with the borehole wall. The fluid extracted from the formation into the evaluation of the downhole tool within the cavity and moves within the evaluation of the cavity, wherein the data collected while the fluid is moved within the evaluation space.

In one embodiment, the process pressure inside the cavity changes continuously estimated during data collection.

In another embodiment of the method the boiling point of the fluid is determined based on the collected data.

In yet another embodiment of the process estimated cavity is formed as a bypass loop of a main channel, and the method further comprises the steps of removing the fluid from the main channel to a separate evaluation cavity circulation allotted fluid within a separate evaluation of the cavity, and collecting data of the designated fluid inside a separate evaluation of the cavity during fluid circulation time allotted.

In a further embodiment, the fluids are in separate cavities estimates may be mixed and then the mixed fluid may be recycled. Then, data is collected on a mixed fluid during recirculation of mixed fluid.

In one aspect, a device for fluid communication with a double seal and an unknown fluid is a pure fluid.

So that the above features and advantages of the present invention can be understood in detail, a more particular description of the invention briefly summarized above, may be used for reference to the embodiments thereof which are illustrated in the accompanying drawings. Note, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not be considered as limiting its scope, and that the invention is susceptible to other equally effective embodiments.

1 is a schematic partial cross-sectional views of a downhole tool having a device for analyzing the fluid, and lowered into the well from a rig.

2 is a schematic partial cross-sectional view of a downhole drilling tool having a device for analyzing the fluid, and lowered into the well from a rig.

3 is a schematic representation of a portion of a downhole tool of FIGURE 1 having a probe mounted in front of the side wall of the borehole and the estimated channel device for analyzing a fluid communication with the internal channel, delivering the formation fluid from the probe.

4 is a schematic representation of yet another embodiment of the downhole tool of FIGURE 1 having a probe mounted in front of the side wall of the borehole, and the estimated channel device for analyzing a fluid communication with the internal channel, delivering the formation fluid from the probe.

5A is a schematic representation of part of another embodiment of the downhole tool of FIGURE 1 having a probe mounted in front of the side wall of the borehole, and the estimated channel device for analyzing a fluid communication with the internal channel, delivering the formation fluid from the probe.

5B is a schematic representation of the downhole tool of Figure 5A illustrating movement of formation fluid within the evaluation channel.

6 is a schematic representation of a portion of another embodiment of the downhole tool of FIGURE 1 having a probe mounted in front of the side wall of the borehole, and the estimated channel device for analyzing a fluid communication with the internal channel, delivering the formation fluid from the probe.

7 is a schematic representation of a portion of another embodiment of the downhole tool shown in Figure 1, having a double tube mounted opposite side wall of the well, and the estimated channel device for analyzing a fluid communication with the internal channel, delivering the formation fluid from the probe.

Some terms are defined in this description as they are first used, while some others used in this specification, the terms are defined below.

"Annular" means provides or forms a ring, i.e. a line feed arrangement or in the form of a closed curve such as a circle or ellipse.

"Contaminated fluid" means fluid which is generally unacceptable for hydrocarbon fluid sampling and / or evaluation because the fluid contains contaminants such as filtrate from the mud used in drilling the well.

"Downhole tool" means instruments placed into the wellbore through the drill string, rope or rolled piping for performing downhole operations related to the evaluation, production, and / or control one or more subterranean formations investigated.

"Promptly connected" means directly or indirectly connected for transmitting or conducting information, force, energy or matter (including fluids).

"Clean fluid" means the subterranean fluid that is relatively clean, the original, natural, non-contaminated, or in any other manner considered in the sampling and analysis of in an acceptable manner to represent that the correct formation of the sampling or evaluation of the hydrocarbon.

"Fluid" and means "pure fluid" and "fluid is dirty."

"Continuous" means marked by uninterrupted length of time, space, or sequence.

Preferred embodiments of the invention described above are shown in the drawings and discussed in detail below. In describing the preferred embodiments, like or identical reference numerals are used to identify common or similar elements. The drawings are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or shown schematically for clarity and the best expression.

1 shows a downhole tool 10 constructed in accordance with the present invention, lowered from the rig 12 into the barrel 14 of the well. The downhole tool 10 may be any type of tool, capable of performing formation evaluation, such as drilling tools, rolled pipe or other downhole tool. The downhole tool is a conventional tool 10 descends from the rig 12 into the barrel 14 via the cable hole 16 and a cable positioned adjacent to the formation F. Example of a wireline tool that can be used are described in U.S. Patents 4,936,139 and №№4860581.

The downhole tool 10 is equipped with a probe 18 adapted for a tight connection with the wall 20 of the barrel 14 wells (hereinafter referred to as "wall 20" or "wall 20 of wellbore") and fluid extraction of the formation F into the downhole tool 10 as indicated by arrows. Auxiliary pistons 22 and 24 facilitate ejection of the probe 18 of the downhole tool relative to the wall 20 of the borehole. The downhole tool 10 is also provided with a device 26 for analyzing the fluid, constructed in accordance with the present invention for the analysis of the formation fluid. In particular, the device 26 is capable of performing formation evaluation and / or analysis of downhole fluids, such as fluids of the formation F. The apparatus 26 receives a formation fluid from the probe 18 through the channel 46 estimated.

2 shows another embodiment of the downhole tool 30, constructed in accordance with the present invention. A downhole drilling tool 30 is a tool that can be moved from one or more (or can be itself) drilling tools for measurement while drilling, the drilling tool for logging while drilling or other drilling tool known to those skilled in the art. The downhole tool 30 attached to drill string 32 driven by a drilling rig 12 to form the wellbore 14.. The downhole tool 30 includes a probe 18a, adapted for a tight connection with the wall 20 of the wellbore 14. Fluid to extract their formation F into the downhole tool 30 as indicated by arrows. The downhole tool 30 is also provided with a device 26 for analyzing the formation fluid recovered into the downhole tool 30. The apparatus 26 receives a formation fluid from the probe 46 via the passageway 18a.

While Figures 1 and 2 show apparatus 26 for a downhole fluid analysis device should be appreciated that such a device may be provided at the wellsite or other equipment to perform the testing fluid. By placing the device 26 for analyzing the fluid in the borehole, a downhole fluid data can be collected in real time. However, as may be desirable and / or necessary to test fluids at the surface or elsewhere. In these cases the device for analyzing the fluid may be placed in the housing, movable to a desired location. Alternatively, the sample can be delivered to the surface or another location and tested in the fluid analysis module, in this place. Data and results from various test sites can be analyzed and compared.

3 is a schematic view of a portion of the downhole tool 10 shown in Figure 1, the system 34 depicting fluid flow. Probe 18 preferably extends from the housing 35 of the downhole tool 10 to come into contact with the wall 20 of the borehole. Probe 18 is provided with a seal 36 for sealing contact with the wall 20 of the borehole. Seal 36 contacts the borehole wall 20 and forms a tight contact with the filter cake of mud 40, 14 overlying the barrel hole. The filter cake 40 seeps into the borehole wall 20 and creates a zone 42 around the barrel 14 of the penetration hole. Zone 42 includes the penetration of drilling mud and other fluids of the borehole, which contaminate the surrounding formations, including a portion of the formation F and clean fluid 44 contained therein.

The system 34 includes an evaluation of the fluid flow channel 46 extending from the inlet of the probe 18. While the probe is depicted to draw fluid into the downhole tool, the other device for communication with the fluid can be used. Examples of devices for communicating with a fluid, such as probes and double seals are used to draw fluid into the channel, are shown in U.S. Patents 4,936,139 and №№4860581.

Estimated channel 46 extends into the downhole tool 10 is used to pass fluid such as a clean fluid 44 in the downhole tool 10 for preliminary testing, analysis and / or sampling. Estimated channel 46 extends into the sample chamber 50 for collecting samples of clean fluid 44. The fluid flow system 34 may also include a pump 52 used for passing fluid through the duct 46.

While Figure 3 shows an exemplary configuration of a downhole tool used to draw fluid from the formation, it should be taken into account by those skilled in the art that can be used in a variety of configurations of channels, pumps and sample chambers, valves and other devices, and it is not intended to limit the scope of the invention.

As discussed above, the downhole device 10 is provided with a device 26 for analyzing the formation fluid. In particular, the device 26 is capable of downhole measurements, such as the phase measurement of viscosity and / or density of the formation fluid. In general, the device 26 is provided with a test fluid analysis chamber 60, a device 62 for moving the fluid discharge node 64 and one or more sensors 66 (a plurality of sensors shown in Figure 4, 5A, 5B, 6 and 7 and numbered for clarity reference numerals 66a-g).

The test chamber 60 forms an evaluation cavity 68 for receiving formation fluid. It should be understood that the test chamber 60 may have any configuration capable of receiving formation fluid and allowing displacement fluid as discussed herein, so that could be measured. For example, as shown in Figure 3, test chamber 60 may be realized as a bypass channel communicating with the estimated channel 46 so that formation fluids can be placed or laid in the flow channel. The apparatus 26 for analyzing the fluid may also be provided with a first valve 70, second valve 72, third valve 74 for selectively diverting fluid from the formation into the testing chamber 60, as well as to isolate the test cell 60 of the estimated channel 60.

As shown, the formation fluid to drain into the test chamber 60 a first valve 70 and second valve 72 are opened, while the third valve 74 is closed. This diverts the formation fluid in the testing chamber 60, while the pump 52 moves the fluid formation. Then, the first valve 70 and second valve 72 are closed to isolate or lock the formation fluid within the test chamber 60. If desired, the third valve 74 may be opened for admitting a normal operation of the downhole tool 10. For example, the valve 74 can be opened and valves 70 and 72 are closed during the evaluation of the fluid in the testing chamber 60. Additional valves and test chambers or channels can be added as desired to facilitate fluid flow.

The device 62 serves to move fluid to move and / or mixing fluid in the evaluation of the cavity 68 to improve the uniformity of cavitation and fluid circulation. The fluid preferably travels through the cavity of the estimated 68 to improve the accuracy of the measurements obtained from the sensor or sensors 66. In general, the device 62 to move the fluid has a force means a force is applied to the formation fluid to cause the formation fluid within the evaluation cavity recycled 68.

Device 62 may be any type of device capable of applying pressure to the formation fluid to force the fluid formation recycle and, optionally, mixed in cavity 68. The evaluation device 62 causes movement of fluid recycle formation fluid in the testing chamber 60 past the sensor or sensors 66. The apparatus 62 displacement fluid may be a pump or any type of device capable of forcing the formation fluid to circulate in the test chamber 60. For example, a device 62 for moving the fluid may be positive displacement pumps such as gear pump, a lobe pump, a screw pump, a vane pump, a peristaltic pump or the piston and a screw pump.

When the device 62 mixes the fluid, one of the sensors 66 (typically defined as a light absorption sensor) can be disposed immediately close to the discharge side of the device 62 to be in the vortex formed by the device 62. The sensor 66 may be any type of sensor capable of measuring parameters of fluid such as a sensor or a device that performs measurement of light absorption.

Preferably, the discharge unit 64 changes the pressure of the formation fluid in the testing chamber 60 continuously. The delivery unit 64 may be any type of device capable to communicate with test chamber 60, and continuously change (and / or incrementally changing) volume or pressure of the formation fluid in the testing chamber 60. In the embodiment shown in Figure 3, the discharge unit 64 is provided with a decompression chamber 82, housing 84, piston 86 and means 88 controls the movement of the piston. The piston 86 has an external surface 90 which cooperates with the housing 84 to define a decompression chamber 82. The control means 88 controls the movement of the piston position of the piston 86 in the housing 84 to effectively change the volume of the decompression chamber 82.

As the change in volume of the decompression chamber 82 volume or pressure in the test chamber 60 also changes. Thus, increasing the decompression chamber 82, the pressure in the test chamber e 60 decreases. Similarly, decreasing the decompression chamber 82, the pressure in the test chamber 60 increases. The means 88 controls the movement of the piston can be an electronic and / or mechanical means of any type capable of performing the change in position of the piston 86. For example, the means 88 controls the movement of the piston may be a pump to the fluid exerts a force on the piston 86, or the motor is movably connected to the piston 86 via a mechanical connection such as a pin, a flange or a threaded screw.

Sensor 66 may be any type of device capable of receiving information that is useful in the determination of fluid properties such as phase behavior of the formation fluid. Despite the fact that only one sensor 66 is shown in Figure 3, the apparatus 26 for analyzing the fluid may be provided by more than one sensor 66, as shown for example in Figures 6 and 7. The sensor 66 may be, for example, sensor Pressure, temperature sensor, density, viscosity sensor, a camera, light sensor, a sensor in the near infrared spectrum to acquire. Preferably, at least one of the sensors 66 used for measuring the absorption of light. In this example, the sensor 66 may be positioned close to a window (not shown) so that the sensor 66 can be visible or perform determination according to a phase change of the formation fluid. For example, the sensor 66 may be a video camera, which may allow single observation of the formation fluid, or to make images of the formation fluid flowing past the window so that the image can be analyzed for the presence of bubbles or other signs of phase change of state of the formation fluid.

Apparatus for analyzing fluid 26 is also provided with a signal processor 94 connected to device 62 for moving the fluid sensor (s) 66, and means 88 controls the movement of the piston. The signal processor 94 preferably controls the means 88 control the movement of the piston and the device 62 to move the formation fluid in the testing chamber 60. The processor can also continuously change the pressure of the formation fluid in a predetermined manner. Despite the fact that the signal processing unit 94 is described here as soon as the pressure changes in the test chamber 60 is continuous, it should be understood that the signal processing unit 94 is adapted to change the pressure in the test chamber 60 in any predetermined manner. For example, the signal processor 94 can control the vehicle motion control piston 88 continuously, incrementally or combined. The signal processor 94 also serves to collect and / or manipulating the data issued by the sensor or sensors 66.

The signal processor 94 may communicate with the device 62 moving the fluid sensor (s) 66 and / or vehicle motion control piston 88 by any suitable communication link, an infrared link, a microwave link or the like. Despite the fact that the signal processor is illustrated as located in a housing 35 of the downhole tool 10, it should be understood that the signal processor 94 may be provided remotely with respect to the downhole tool 10. For example, the signal processor 94 may be provided in a control station situated at a wellsite or located remotely with respect to the drilling site. The signal processor 94 includes one or more electronic or optical devices capable of performing logic to control the unit 62 moving fluid, and means 88 controls the movement of the piston, as well as collecting information from the sensor (s) 66 described herein. Signal processor 94 can also interact with and control the first valve 70, second valve 72 and third valve 74 for selectively diverting fluid to and from the estimated cavity 68 as discussed above. For clarity, the lines showing the relationship between the signal processor 94 and the first valve 70, second valve 72 and third valve 74 in Figure 3 have been omitted.

As used processor 94 can be used to selectively actuate the valves 70, 72 and / or 74 for discharging the formation fluid in the test chamber 60, as discussed above. The signal processor 94 may close valves 70 and 72 for the isolation or blocking of the formation fluid in the testing chamber 60. The signal processor 94 may then actuate the device 62 for moving the fluid to move the formation fluid in the testing chamber 60 in recirculation mode. As shown in Figure 3, this forms a recirculation loop which passes through the discharge unit 64, the sensor 66 and the displacement of the fluid device 62. This loop is formed from a number of channels, the combined channel for the movement of the fluid stream to form a loop. In small spaces, such as downhole tool, the fluid usually travels through the narrow channels. Agitation in such narrow channels generally difficult. Fluid thus circulates in a loop to increase mixing of the fluid as it passes through narrow channels. Such agitation may also be desirable in other applications that do not include narrow channels.

The signal processor 94 actuates the control means 88 to initiate movement of the valve changes the pressure in the test chamber 60 in a predetermined manner. In one example, the signal processor 94 actuates the means 88 of motion control valve to continuously reduce the pressure of the formation fluid in the test chamber 60 at a rate suitable for phase measurement in a short time, sometimes less than 15 minutes. While in the test chamber 60 pressure decreases continuously, the signal processor 94 collects data from the sensor or sensors 66 for measurement of the preferred absorption of light (i.e. scattering), while also controlling the pressure in the test chamber 60 to provide an accurate measurement of the phase behavior of the formation fluid .

The downhole tool 10 is also provided with a fourth valve 96 for selectively diverting the formation fluid into the sample chamber 50, or into the barrel 14 through the return channel well 98. The downhole tool 10 may also be provided with an output port 99, it slides out of the back of the sample chamber 50.

It should be understood that the apparatus 26 for analyzing the fluid may be used in various ways in downhole tools 10 and 30. The above description regarding insertion device 26 for analyzing the fluid in the downhole tool 10 is equally applicable to a downhole tool 30. Additionally, various modifications of the downhole tools 10 and 30 relative to the apparatus 26 for analyzing the fluid treated by the present invention. Many of these modifications will be described below with respect to the downhole tool 10. However, it should be understood that these modifications are equally applicable to a downhole tool 30.

It should be understood that measuring the phase behavior are not the only type of measurements that can be made, and because it is likely that the determination of the phase boundaries is more sensitive to stirring, it is also desirable for precise measurements, such as density in a multicomponent mixture and also for the viscosity . Indeed, measurements can be made with a continuous or step-down the pressure. In the case of stepping, an additional operation becomes possible by performing the pressure reduction to the boundary phases twice with the same sample or, preferably, with a certain part of the fresh fluid from the channel. If it is adapted to discrete pressure steps, the first drop in pressure with constant pressure reduction leads to a rough estimate of the phase boundary pressure. A rough estimate can be used in the second cycle of pressure reduction with a logarithmically decreasing step sizes used for reducing pressure, such amount of decrease in pressure decreases logarithmically (or some other mathematical method in which the amount of decrease in pressure decreases) with decreasing pressure in aspiration pressure to evaluation obtained in the first measurement. At a pressure lower than the estimated size of the step, the pressure increases with decreasing pressure. This procedure can give a more precise answer.

The temperature and the much smaller magnitude of the pressure in the downhole tool 10 or 30 can be unequal temperature and pressure in the tank F. To obtain estimates of in an appropriate condition from the values ​​measured under the conditions of the downhole tool 10, or 30, preferably comprising a temperature estimation and tank pressure and change in properties a change in temperature and pressure, these values ​​are combined with a model that can be extrapolated from one set of temperatures and pressures other set. Thus, it is desirable to perform measurement in this zone during zone shift or extraction of the downhole tool 10 or 30 so that the desired deviation can be measured and then combined with the equation of state.

4-7 will now be described. To simplify the signal processor 4-7, 94 and respective link not shown.

Figure 4 shows the downhole tool 10a, which is similar in construction and function to the downhole tool 10 described above with reference to Figure 3, except that the downhole tool 10a is provided with two units 26 for fluid analysis. The advantage of having a plurality of devices 26 for fluid analysis allows the downhole tool 10a to receive some formation fluid samples and their testing simultaneously or intermittently. This allows you to compare the results of samples, providing better precision downhole measurements. Despite the fact that only two devices 26 for the fluid analysis shown in Figure 4, it should be understood that the downhole tool 10a may be provided with any number of units 26 located at various locations downhole tool. In the embodiment shown in Figure 4, each device 26 selectively communicates with the estimated channel 46. It should also be understood that the device 26 for analyzing the fluid can operate independently and / or used to independent channels.

5A and 5B show the downhole tool 10b, which is similar in construction and function to the downhole tool 10 described above with reference to Figure 3, except that the downhole tool 10b includes a pump assembly 180 that combines the functions of device 62 displacement fluid and discharge assembly 64 shown in Figure 3. 5A shows the downhole tool 10b to the pump assembly in the upper position, Figure 5B shows the downhole tool 10b and the pump head in its lower position. The pump unit 180 is provided with a first receptacle 182, the second vessel 184, the piston assembly 186 and the driving force source 188.

The piston assembly 186 includes a first body 192 movably placed in the first vessel 182 to form first chamber 193 communicating with the cavity 68. Assessment The piston assembly 186 also includes a second body 194 slidably housed in the second vessel 184 to form a second chamber 196 communicating with the appraised cavity 68. 5A and 5B illustrate the movement of the first and second bodies 192 and 194.

Source 188 motive force moves the first and second bodies 192 and 194 of the piston assembly 186 such that the formation fluid received by the test chamber 60 is withdrawn past the sensors 66a-e and between the first and second chambers 193 and 196 as a change in relative positions of the first and second bodies 192 and 194. To change the pressure during the movement of the first and second bodies 192 and 194, the first chamber 193 has a diameter A and the second chamber 196 has a diameter B. The diameter B preferably is smaller than diameter A. As the first and second chambers 193 and 196 have different diameters, the combined volume of the first chamber 193, second chamber 196 and the estimated cavity 68 varies as the motion of the first and second bodies 192 and 194.

Source 188 drive force simultaneously moves the first and second bodies 192 and 194 in the first direction 200, as shown in Figure 5B to cause the formation F to move fluid from the second chamber 196 into first chamber 193 past the sensors 66a-e during pressure reduction in the evaluation cavity 68. For example, if during the movement over a distance (ds) the first body 192 in the first chamber 193 draws approximately 5 cm3 of fluid and the second body 194 in the second chamber 196 pushes about 4.8 cm3 of fluid, then there will be a net increase of approximately 0.2 cm3, while about 4.8 cm3 formation fluid F moves past the sensors 66a-e.

Driving force source 188 may be any device or devices capable of moving the first body 192 and second body 194. For example, the piston assembly 186 may include a drive screw 202 is coupled to the first body 192 and second body 194. The driving source 188 may drive force movement of the drive screw 202 by a motor 204 is mechanically coupled to the drive nut 206, located on the drive screw 202. Alternatively, the hydraulic pump can be returned to its original position or control arrangement of the piston assembly 186.

6 illustrates the downhole tool 10c, which is similar in construction and function to the downhole tool 10a, described above with reference to Figure 4, except that the downhole tool 10c further includes one or more isolation valves 220 and 222. The downhole device 10c is provided with two or more devices 26 for fluid analysis. As discussed above with reference to Figure 4, the advantage of having a plurality of devices 26 for fluid analysis allows the downhole tool 10a or 10c to receive several samples and testing formation fluid sample either simultaneously or intermittently. This allows you to compare the results of the samples to provide a better accuracy downhole measurements.

With the addition of isolation valves 220 and 222 connecting the test chamber 60 a device 26 for analyzing the fluid with the test cell 60 of another device 26 for analyzing the fluid, the downhole tool allows the isolation valves 220 and 222 to be open, to mix the sample separately received in the two devices 26 fluid analysis. Isolation valves 220 and 222 can be closed and then mixed fluids tested separately formation device 26 for analyzing the fluid.

7A is a downhole tool 10d, which is similar in construction and function to the downhole tool 10a, described above with reference to Figure 4, except that the downhole tool 10d is additionally provided with a probe 230 having a channel 232 in addition to cleaning the estimated channel 46, and a device 26 for analyzing the fluid channel 232 connected to cleaning. The downhole tool 10d is also provided with a pump 234 connected to channel 232 for extracting the contaminated cleaning fluid from the formation and to remove contaminated fluid into the device 26 for analyzing the fluid.

The apparatus 26 may be used for fluid analysis and evaluation for the purification of channels 46 and 232. The information received from the device 26 for analyzing the fluid, could be used to determine information such as pollution levels. As shown, the estimated channel 46 is connected to the sample chamber 50 so that fluid samples can be selected. Such sampling is usually the case when pollution levels are falling below the accepted level. Channel 232 is depicted as cleaning coupled with the barrel 14 wells for fluid discharge from the tool 10d. Optionally, various valves fittings may be provided for selectively diverting fluid from one or more channels as desired into the sample chamber or the wellbore.

While the above-described downhole tools are shown as having probes to draw fluid into the downhole tool, one skilled in the art should take into account that can be used in other devices to draw fluid into the downhole tool. For example, a double radial seals may be located near the inlet of one or more channels for insulation between the barrel 14 and fluid extraction wells in the downhole tool.

Additionally, while the device 26 for fluid analysis has been shown and described herein in combination with downhole tools 10, 10a, 10b, 10c, 10d and 30, it should be understood that it may be used in other environments, such as setting the portable lab or stationary laboratory conditions.

It will be appreciated from the foregoing description that various modifications and changes may be made in the preferred and alternative embodiments of the present invention without departing from its spirit.

This description is intended for illustrative purposes only and should not be construed in a limiting sense. The scope of the invention should only be defined by the language of the appended claims. The term "comprising" in the claims should be interpreted as "including at least" such that the said list of elements in the claims is an open group. Indefinite articles and other singular forms are included in themselves and their plural forms, unless specifically excluded.