CN1800578B - Apparatus and method for formation evaluation - Google Patents

Abstract

A viscometer-densimeter for a down hole tool positionable in a well bore penetrating a subterranean formation is described. The formation contains at least one fluid therein. The down hole tool is adapted to convey at least a portion of the fluid to the viscometer-densimeter. The viscometer-densimeter comprises a sensor unit, and at least one magnet. The sensor unit is positionable within the down hole tool and comprises at least two spatially disposed connectors and a wire suspended in tension between the at least two connectors such that the wire is available for interaction with the fluid when the viscometer-densimeter is positioned within the down hole tool and the down hole tool is positioned within the subterranean formation and receives the fluid from the subterranean formation. The connectors and the wire are constructed so as to provide a frequency oscillator.

Description

The apparatus and method that are used for formation evaluation

Technical field

The present invention relates to a kind of technology of carrying out the formation evaluation of subterranean strata by being located at downhole tool in the pit shaft that passes subterranean strata.More specifically but and without limitation, the present invention relates to a kind of for determining fluid parameter, for example being drawn into downhole tool and/or the viscosity of the formation fluid estimated by downhole tool and the technology of density.

Background technology

Get out pit shaft, with location and production hydro carbons.To be advanced into underground with the downhole drill instrument of drill bit at the one end, to form pit shaft.When drilling tool advanced, drilling mud just pumped into by drilling tool and flows out drill bit, in order to cool off drill bit and take smear metal out of.Drilling mud has formed the mud cake of lining on shaft in wall in addition.

In drill-well operation, need to carry out various evaluations to the rock stratum that pit shaft passes.In some cases, drilling tool can take off, and the plain conductor instrument can be expanded in the pit shaft the rock stratum is tested and/or sampled.Under other situation, drilling tool can be provided with the device that rock stratum is on every side tested and/or sampled, and drilling tool can be used for testing or sampling.These samples or test case are as can be used for locating valuable hydro carbons.

The common requirement of formation evaluation will from the fluid suction downhole tool of rock stratum to test or to sample.Various devices stretch out from downhole tool such as probe so that forming fluid with pit shaft rock stratum on every side is communicated with, and with in the fluid suction downhole tool.Typical probe is from circular piece, and it stretches out from downhole tool, and is positioned to abut on the sidewall of pit shaft.The rubber packer of an end of popping one's head in is used to form the sealing with well bore wall.Another device that is used to form with the sealing of pit shaft is called dual tubing packing.By dual tubing packing, two elastomeric ring around tools radially open in order to isolate a part of pit shaft between them.These rings have formed the sealing with well bore wall, and allow fluid to be pumped in the isolated part of pit shaft and enter in the entrance of downhole tool.

The mud cake of liner on pit shaft is generally used for helping probe and/or dual tubing packing and well bore wall to form sealing.In case formed sealing, just be drawn in the downhole tool by entrance by reducing the pressure in the downhole tool from the fluid of rock stratum.Be used for downhole tool probe and/the visible U.S. Patent No. 6301959 of example of dual tubing packing, 4860581,4936139,6585045,6609568 and 6719049 and U.S. Patent application No.2004/0000433.

Usually carry out the evaluation of rock stratum based on suction to the fluid in the downhole tool.For the prior art of carrying out various measurements the fluid that enters downhole tool is tested and/or sample collection in advance.Yet, have been found that when formation fluid enters downhole tool various pollutants such as wellbore fluids and/or drilling mud can be in company with in the formation fluid together entering tool.These pollutants can affect the quality of measurement and/or formation fluid sample.In addition, pollution can cause expensive wellbore operations to postpone, because need the more time for test and/or sampling.In addition, these problems can produce wrong and/or disabled untrue result.

Therefore, need to enter the formation fluid enough " cleaning " and " pure " of downhole tool to be used for carrying out correct test.In other words, formation fluid should have little or no pollution.Carried out multiple trial to attempt to remove the pollutant that enters together downhole tool in company with formation fluid.For example, as described in U.S. Patent No. 4951749, strainer is set in probe, enters downhole tool with block contaminant with formation fluid.In addition, as authorize as described in the U.S. Patent No. 6301959 of Hrametz, probe is provided with protection ring, opens in order to contaminated fluids shunted with clean fluid when entering probe.The fluid that enters downhole tool is usually by the stream pipeline, and can capture in sampler chamber or be pumped in the pit shaft.Various valves, scale and other parts can be along the stream pipeline installings, in order to shunt, test and/or catch the fluid through downhole tool.

Can test the fluid by downhole tool, in order to determine various downhole parameters or performance.Fluid phase performance under the thermophysical property of hydrocarbon reservoir fluid such as viscosity, density and the storing state can be used for estimating potential reserves, determines the stream in the porous media, and design completion, separation, processing and metering system, etc.

Having developed various technology comes for the viscosity of measuring fluid.For example, a kind of viscometer that is suspended on the plummet between the torsion wire fixed point that has has been proposed also, for example described in U.S. Patent No. 5763766 and 6070457.Viscometer is also formed by vibrating object.A kind of viscometer like this has been used for down-hole application, to be used for measuring the formation fluid of hydrocarbon well or viscosity, density and the dielectric constant of exudate.For example, international publication WO 02/093126 discloses a kind of tuning fork resonator in pipe, in order to provide measure in real time directly and the evaluation hydrocarbon well in formation fluid or viscosity, density and the dielectric constant of exudate.Also used another kind of viscometer under laboratory condition, it has and is clipped in two wires between the pillar, for example sees The Viscosity of Pressurized He above T _λ, Physica (1974) 177-180; Vibration wire type viscometer, The Review of Scientific Instruments Vol.35, No.10 (in October, 1964), 1345-1348 page or leaf.

Although exist to be used for measure the technology of viscosity, but still the viscosity measurement of accurate down-hole need to be provided, preferably and downhole sensor with respect to the location independent of gravitational field.More satisfactory is that this system can check precision and/or accuracy.More satisfactory is that this system has simple structure, to be applicable in the harsh wellbore environment in addition.

Summary of the invention

On the one hand, the present invention relates to a kind of viscometer-densometer of the downhole tool for can be positioned on the pit shaft that penetrates subterranean strata.This downhole tool is suitable for the Fluid Transport at least a portion rock stratum to viscometer-densometer.This viscometer-densometer comprises the sensor unit that can be located in the downhole tool.This sensor unit comprises at least two connector, wire and at least one magnet that spatially arrange.Be suspended between these at least two connectors to this wire tensioning, so that be located in the downhole tool and downhole tool is located in the ground in the rock stratum and when accepting to come from the fluid of subterranean strata when viscometer-densometer, this wire can be used for and fluid produces and interacts.Connector becomes with wire configurations can provide frequency oscillator.This at least one magnet sends and the interactional magnetic field of this wire.

This connector can be made of the material with similar coefficient of thermal expansion with wire, so that frequency oscillator to be provided.For example, this connector and wire can be made of homogenous material, change in order to basically eliminate the resonant frequency that the thermal deformation that causes because of the down-hole state and elastic deformation cause.Viscometer-densometer also can be provided with the stream pipe, and wherein wire is hung up by connector, and in this case, stream pipe, connector preferably are made of the material with similar coefficient of thermal expansion with wire, so that frequency oscillator to be provided.

On the other hand, sensor unit also is provided be used to preventing the device of wire with respect to the connector rotation.Be used for preventing that this device of wire rotation from can comprise the protuberance (boss) that is connected on the wire, wherein this protuberance has non-circular cross section.

On the other hand, viscometer-densometer also is provided with the analysis circuit that can receive the feedback that comes from wire, is used at least two parameters (for example viscosity and density) of calculating and the interactional fluid of wire.

On the other hand, the present invention relates to a kind of downhole tool that is located in the pit shaft, this pit shaft has wall and has penetrated subterranean strata.This rock stratum generally has fluid, for example is included in wherein natural gas or oil.Downhole tool is provided with shell, and fluid is communicated with device, and viscometer-densometer.This shell seal at least one estimate cavity.Fluid is communicated with device and can stretches out from shell, in order to engage with the wall of pit shaft is sealed.This fluid is communicated with device and has at least one entrance, its with estimate cavity and be connected, being used for accepting the fluid from the rock stratum, and this fluid is stored in the evaluation cavity.Viscometer-densometer is provided with and is positioned at the sensor unit of estimating cavity.This sensor unit is provided with at least two connector, wire and the magnets that spatially arrange.Be suspended between these at least two connectors to this wire tensioning so that wire can with the fluid interaction of estimating in the cavity.Connector becomes with wire configurations can provide frequency oscillator.This at least one magnet can send and the interactional magnetic field of wire.This viscometer can be the viscometer of above-mentioned any model.

On the other hand, downhole tool can be provided with the comparison chamber, and it has comprised the fluid with known performance such as viscosity and density.Relatively down-hole state such as the pressure and temperature in the chamber is similar to the down-hole state in (preferably being equal to) evaluation cavity.This downhole tool also is provided with the sensor unit that is in the comparison chamber, be located at a sensor unit of estimating in the interior unknown parameter fluid of cavity so that downhole tool comprises, and be located at another sensor unit in the interior known parameters fluid of comparison chamber.Then, the signal that represents at least two unknown parameters (for example viscosity and density) of estimating the cavity inner fluid is calculated.

On the other hand, the present invention relates to the method that at least two unknown parameters of the unknown fluid in the pit shaft of the rock stratum that comprises fluid are passed in a kind of measurement.In the method, the fluid of downhole tool connection device is arranged to engage with the wall of pit shaft is sealed.Then, fluid is extracted out from the rock stratum, and inserted in the interior evaluation cavity of downhole tool.Utilize viscometer-densometer that the data of estimating the fluid in the cavity are sampled, this viscometer-densometer has to be located to be estimated in the cavity and is suspended on two wires between the connector.This wire becomes with connector structure can provide frequency oscillator.

In this respect, estimating cavity can be streamline (flow line) or sampler chamber.By the data that viscometer-densometer is sampled and obtained, just can utilize these data that sampling obtains in estimating cavity to calculate at least two parameters.These at least two parameters comprise viscosity and density.

On the other hand, the method also comprises the step of the known fluid in the chamber relatively being carried out data sampling, this fluid have with estimate cavity in the relevant temperature and pressure of the temperature and pressure of fluid.In this case, the method generally also comprises, utilizes the data that gather and from estimating the data that gather in the cavity, calculate at least two parameters estimating the unknown fluid in the cavity from chamber relatively.

On the other hand, the present invention relates to a kind of computer-readable media, it can be located at or be included in for the analysis circuit that calculates at least two fluid parameters such as viscosity and density.In this case, these computer-readable media comprise logical gate, be used for (1) reception from the feedback of at least two sensor units, one of them sensor unit is located in the fluid of unknown parameter, another sensor unit is located in the fluid of known parameters, and (2) calculate the signal of at least two unknown parameters of the fluid that representative wherein is provided with a sensor unit, basically eliminates simultaneously the variation of the folding state around the sensor unit that is in the unknown parameter fluid.This logical gate for calculating signal for example can comprise be used to the logical gate that carries out from the joint inversion of the data of sensor unit.

In above-mentioned every one side of the present invention, preferably side by side calculate described at least two fluid parameters.

Description of drawings

Therefore, by the embodiment shown in the reference accompanying drawing, can at length understand above-mentioned feature and advantage of the present invention, and as outlined above more specifically description of the present invention.Yet, should be noted that accompanying drawing has only shown exemplary embodiments of the present invention, therefore should not be considered as having limited scope of the present invention, because the present invention can allow other equivalent embodiment.

Fig. 1 is the show in schematic partial sections with inner viscometer-densitometric down-hole plain conductor instrument, and the plain conductor instrument suspends in midair from boring tower.

Fig. 2 is the show in schematic partial sections with inner viscometer-densitometric down-hole equipment, and down-hole equipment suspends in midair from boring tower.

Fig. 3 A is the schematic diagram of the part of downhole tool shown in Figure 1, and it has the probe on the sidewall that is aligned in the pit shaft and is located at viscometer-densometer in the evaluation streamline in the downhole tool.

Fig. 3 B is the schematic diagram of another pattern of downhole tool shown in Figure 1, and it has the purification streamline that uses with dual tubing packing.

Fig. 4 is provided in a side of the interior viscometer of evaluation cavity-densitometric lateral view.

Fig. 5 is the sectional view of viscometer shown in Figure 4-densitometric sensor unit, has shown the wire that hangs.

Fig. 6 is the decomposition diagram of viscometer shown in Figure 4-densitometric sensor unit.

Fig. 7 A is logical flow chart, has shown the method that is used for side by side calculating viscosity and density.

Fig. 7 B is logical flow chart, has shown the other method that is used for side by side calculating viscosity and density.

Fig. 8 has shown fixedly f ₀Hyperplane is handed over the figure of the card side's performance face that cuts, and has shown minimum value used when bulk density and viscosity.

Fig. 9 is the decomposition diagram of another sensor unit of viscosity-density.

Figure 10 is the top plan view of sensor unit shown in Figure 9.

Figure 11 is the lateral view of the sensor unit of another pattern.

Figure 12 is the sectional view of the sensor unit shown in Figure 11 cut open along Figure 11 center line 12-12.

Figure 13 is the schematic fragmentary of the downhole tool of another pattern, it has two or more viscometer-densometers, one of them viscometer-densometer is located in the fluid of unknown viscosity and density, and another viscometer-densometer is located in the fluid of known-viscosity and density.

Figure 14 A is logical flow chart, has shown a kind of be used to utilizing the method for side by side calculating viscosity and density that arranges shown in Figure 13.

Figure 14 B is logical flow chart, has shown the another kind of method of side by side calculating viscosity and density that arranges shown in Figure 13 that is used for utilizing.

The specific embodiment

Below introduce in detail currently preferred embodiments of the present invention as shown in above figure.When describing these preferred embodiments, similar or identical label is used for representing common or similar parts.These accompanying drawing not drawn on scale, for clarity and brevity, the some of them view may show with the ratio of amplifying or schematically show.

Definition

Some term is defined when using for the first time in this manual, and the in this manual as follows definition of some other term:

" annular " means or relates to and form ring, namely is shaped as closed curve such as circular or oval-shaped line, band or setting.

" contaminated fluids " means for hydro carbons sampling and/or to estimate generally be unacceptable fluid, for example gas or liquid, because this fluid comprises pollutant, and the filtrate of used mud when for example coming from the drilling well cylinder.

" downhole tool " means to be set to the instrument in the pit shaft by utensil such as drill string, plain conductor, flexible pipe, is paid close attention to one with evaluation, the production of a plurality of subterranean stratas and/or manage relevant downhole operations with institute to be used for carrying out.

" connect operatedly " and mean directly and the connection of being connected, with for transmission or conducts information, power, energy or material (comprising fluid).

" pure fluid " means enough pure, original, primary, not comtaminated or be regarded as characterizing acceptably given rock stratum to be used for correct hydro carbons sampling and/or the underground fluid of estimating, for example gas or liquid in sampling fluids and analysis field.

" fluid " means " pure fluid " or " contaminated fluids ".

" clamp " thus mean to be designed to can with two or more component in conjunction with or constraint be pressed together they devices of getting up of clamping securely.

" connector " means for connecting rigidly or any device or the assembly of the part of clamping wires, for example clamp.

" frequency oscillator " means the resonant frequency of tensioning wire in the vacuum (hereinafter referred to as " f ₀") be predictable; so the variation of wellbore conditions such as temperature and pressure do not have a great impact the resonant frequency of tensioning wire, thereby the reading that obtains from the tensioning wire under the wellbore conditions that changes has just represented the characteristic with the interactional fluid of tensioning wire acceptably.

Describe in detail

Fig. 1 has shown the downhole tool 10 that consists of according to the present invention, and it suspends in midair and enter the pit shaft 14 from boring tower 12.Downhole tool 10 can be the instrument that can carry out any type of formation evaluation, for example drilling tool, flexible pipe or other downhole tool.Downhole tool 10 shown in Figure 1 is to launch to enter pit shaft 14 and be located near the F of rock stratum traditional metal wireline tool from boring tower 12 by metal guide cable 16.Downhole tool 10 is provided with probe 18, and it is suitable for being sealed on the wall 20 (hereinafter referred to as " wall 20 " or " well bore wall 20 ") of pit shaft 14, and will be from the fluid of rock stratum F as shown by arrows in the suction downhole tool 10.Supporting piston 22 and 24 helps the probe 18 of downhole tool 10 is pushed against on the well bore wall 20.

Fig. 2 has described another example of the downhole tool 30 that consists of according to the present invention.Downhole tool 30 shown in Figure 2 is drilling tools, and it can be along with one or more (perhaps itself for) measurement while drilling (MWD) drilling tool, well logging during (LWD) drilling tool or other drilling tool well known by persons skilled in the art transmit.Downhole tool 30 is connected on the drill string 32 that boring tower 12 drives, to form pit shaft 14.Downhole tool 30 comprises probe 18, and it is suitable for being sealed with the wall 20 (hereinafter referred to as " wall 20 " or " well bore wall 20 ") of pit shaft 14, so that will be from the fluid of rock stratum F as shown by arrows in the suction downhole tool 30.Following viscometer-densometer or sensor unit can use with downhole tool 10 or downhole tool 30.

Fig. 3 A is the schematic diagram of the part of downhole tool 10 shown in Figure 1, has shown fluid flow system 34.Probe 18 preferably stretches out from the shell 35 of downhole tool 10, in order to engage with well bore wall 20.Probe 18 is provided be used to the packer 36 that is sealed on the well bore wall 20.Packer 36 contacts with well bore wall 20, and has formed sealing with the mud cake 40 of lining on pit shaft 14.Mud cake 40 infiltrates in the well bore wall 20, and has formed invaded zone 42 around pit shaft 14.This invaded zone 42 includes mud and other wellbore fluids, and they can pollute the rock stratum on every side that comprises rock stratum F and be contained in a part of pure fluid 44 wherein.

Probe 18 preferably is provided with estimates streamline 46.Be used for the fluid connecting device of the fluid suction streamline visible U.S. Patent No. 4860581 of example and 4936139 such as probe and dual tubing packing.

Estimate streamline 46 and stretch in the downhole tool 10, and be used for making fluid such as pure fluid 44 therefrom by entering downhole tool 10, in order to detect and/or sample.Evaluation streamline 46 extends to the sampler chamber 50 for the sample that gathers pure fluid 44.Pump 52 can be used for by streamline 46 pumping fluids.

Although Fig. 3 A has shown the same configuration that is used for from the downhole tool of rock stratum withdrawn fluid, yet persons of ordinary skill in the art may appreciate that probe, streamline and the downhole tool of various structures all are available, and is not to attempt to limit the scope of the invention.

For example, Fig. 3 B is the schematic diagram of a part of the downhole tool 10 of another pattern, the fluid flow system 34a that it has improved probe 18a and is used for the streamline that the fluid suction is independent.More particularly, fluid flow system 34a shown in Fig. 3 B is similar to fluid flow system 34 shown in Fig. 3 A, difference is that fluid flow system 34a comprises the purification streamline 46a except estimating streamline 46, and the pump 52a and the 52b that are associated with corresponding streamline 46 and 46a.The 18a of probe shown in Fig. 3 B is similar to shown in Fig. 3 A and pops one's head in 18, and difference is that probe 18a has two independent cavity 56a and 56b, and its cavity 56a is connected with streamline 46, and cavity 56b is connected with streamline 46a.Cavity 56b surrounding cavity 56a extends, so that cavity 56b can extract " contaminated fluids " from the F of rock stratum, thereby allows cavity 56a can extract " pure fluid " from the F of rock stratum.Contaminated fluids is discharged from purify streamline 46a and is entered pit shaft 14 by exporting 57.Be used for the fluid connecting device of the streamline that the fluid suction is independent such as the visible U.S. Patent No. 6719049 of example and the U.S. Patent application publication number No.20040000433 of probe and dual tubing packing, it transfers assignee of the present invention, and the U.S. Patent No. 6301959 that transfers Halliburton.

According to the present invention, the evaluation cavity in viscometer-densometer 60 (a, b, c) and the downhole tool 10 is associated, for example with estimate streamline 46, purify streamline 46a or sampler chamber 50 is associated, to be used for measuring the viscosity of estimating the fluid in the cavity.In Fig. 3 B example shown, for the sake of clarity, viscometer-densometer 60 has label 60a, 60b and 60c.Viscometer-densometer 60 shows in greater detail in Fig. 4,5 and 6.

Downhole tool 30 also can be provided with shell, probe, fluid flow system, packer, evaluation streamline, purify streamline, sampler chamber, pump and viscometer-densometer, and its mode is similar to the downhole tool 10 shown in Fig. 3 A and the 3B.

Referring now to Fig. 4-6,, the below will describe viscometer-densometer 60 in detail for the evaluation cavity of estimating in the streamline 46.Yet, should be appreciated that following description is equally applicable to purify the evaluation cavity in streamline 46a or the sampler chamber 50.Be introduced in connection with downhole tool 10 although it is also understood that viscometer-densometer 60, yet this introduction is equally applicable to downhole tool 30.In addition, although viscometer-densometer 60 shown in Fig. 3 A and the 3B arranges along streamline 46a and 46b, viscometer-densometer 60 also can be located at for the diverse location place around the downhole tool 10 of measuring downhole parameters.

Generally speaking, viscometer-densometer 60 has sensor unit 62, one or more magnet 64 (a, b), signal processor 66, and analysis circuit 68.In example shown in Figure 4, viscometer-densometer 60 is provided with two magnets, and they are represented by label 64a and 64b in Fig. 4.Sensor unit 62 is provided with at least two connector 72, the wires 74 (Fig. 5) that spatially arrange, it is suspended between two connectors 72 at least, so that be located in the downhole tool 10 and downhole tool 10 is located in the ground in the F of rock stratum and when accepting to come from the fluid of rock stratum F, this wire 74 can be used for and fluid interaction when viscometer-densometer 60.Magnet 64a and 64b send magnetic field, and it interacts with the sinusoidal current that flows through wire 74.Signal processor 66 is via signal path 75a and 75b and wire 74 electric connections.Signal path 75a and 75b can be wire, cable or air way communication line.Signal processor 66 provides the driving voltage that is used to form to the sinusoidal current of wire 74, and it makes wire 74 as one man vibrate or resonance with the signal on it is provided usually.Usually, provide to the signal of wire 74 from signal processor 66 to can be considered the swept frequency constant current signal, wherein signal frequency changes in a predefined manner.

Analysis circuit 68 receives the feedback that comes from wire 74.Sinusoidal current flows through wire 74, when frequency near resonant frequency, when namely being generally the lowest-order pattern, just produced detectable electromotive force (" emf ").Driving voltage and electromotive force emf during as resonance the function of frequency record.Usually, analysis circuit 68 receives the feedback that comes from wire 74, and it represents the resonant frequency of wire 74.According to the viscosity of fluid, the resonant frequency of wire 74 changes in a predefined manner, and this just allows to measure the viscosity of fluid.Come viscometric method with hereinafter more detailed introduction by the feedback that comes from wire 74.Analysis circuit 68 can be the circuit that can receive from any type of the feedback of wire 74 and Fluid Computation viscosity.Usually, analysis circuit 68 comprises computer processor, and it is used for carrying out the software program that is stored on computer-readable media such as the memory disc and calculates viscosity with permission analysis circuit 68.Yet, should be appreciated that in certain embodiments analysis circuit 68 can utilize the device of analog type or other type to implement.For example, analysis circuit 68 can comprise analog-digital converter, is provided with thereafter the decoder for Fluid Computation viscosity.Although analysis circuit 68 and signal processor 66 show individually, yet should be appreciated that analysis circuit 68 and signal processor 66 also can realize in single circuit in Fig. 4, perhaps in independent circuit, realize.In addition, although analysis circuit shown in Figure 4 68 and signal processor 66 are in the downhole tool 10, yet should be appreciated that signal processor 66 and/or analysis circuit 68 also can be located at outside the downhole tool 10.For example, can be located in the downhole tool 10 for generation of the signal processor 66 that scans signal, and analysis circuit 68 is located in the Surveillance center in pit shaft 14 outsides, this Surveillance center can be near pit shaft 14 or away from pit shaft 14.

The sensor unit 62 of viscometer-densometer 60 also is provided with shell 76.The entrance 80 that shell 76 defines passage 78 (Fig. 5 and Fig. 6), is communicated with passage 78, and the outlet 82 that is communicated with passage 78.In example shown in Figure 4, fluid flows through along direction 84 estimates streamline 46.Therefore, when fluid ran into sensor unit 62, fluid just flow through entrance 80, admission passage 78, and leave shell 76 by exporting 82.When shell 76 is provided with when estimating the outside dimension of streamline 46 inside dimensions, a certain amount of fluid also will flow through the passage 87 (Fig. 4) in the shell 76, between the external surface 88 that this passage 87 is formed at shell 76 and the inner surface 89 of evaluation streamline 46.

Wire 74 is located in the passage 78 so that when fluid when the shell 76, fluid will with connector 72 between roughly whole wire 74 contact.This just guarantees that flow crosses the whole length of the wire 74 between the connector 72, in order to help to clear up the wire 74 between the fluid.Wire 74 is made of conductive material, and a plurality of basic model resonant frequencies (or its harmonics) of the fluid viscosity that it can be around the tension force that depends on wire 74 and wire 74 are lower to produce vibration.Wire 74 is made of the material of greater density as required, because the difference of the density of wire 74 and fluid density is larger, then sensitivity is just larger.Wire 74 also needs to have high young's modulus of elasticity so that stable resonance to be provided, and the ratio of density by fluid density and wire density provides the sensitivity to its surrounding fluid simultaneously.Multiple material can be used for wire 74.For example, wire 74 can be made by tungsten or chrome-nickel.When wire 74 was used for probe gas such as natural gas, wire 74 preferably had the external surface of smoother.In this case, chrome-nickel is for the preferred material that consists of wire 74.

As shown in Figure 4, magnet 64 preferably is located at the outside of estimating streamline 46, and is installed on the external surface of estimating streamline 46.Magnet 64 also can be combined in the shell 76.As alternative, shell 76 can be made of magnet material.

As illustrated in Figures 5 and 6, shell 76 can be provided with the first case member 90 and second housing parts 92.The first case member 90 and second housing parts 92 cooperatively interact to limit passage 78.The first case member 90 and second housing parts 92 preferably are made of the nonmagnetic substance of conduction, so that the magnetic field that magnet 64 produces can interact with wire 74, are not subject to the larger interference from shell 76 simultaneously.For example, the first case member 90 and second housing parts 92 can be made of the down-hole compatibility material, for example K500 Monel, tungsten or another kind of nonmagnetic substance, for example stainless steel.

Shell 76 also is provided with insulating layer 96 (Fig. 5), and it is located between the first case member 90 and the second housing parts 92, in order to the first case member 90 is opened with second housing parts 92 electric insulations.Wire 74 extends between the opposite side of insulating layer 96, in order to the first case member 90 is linked to each other with second housing parts 92 electricity.Insulating layer 96 can comprise the first insulating part 98 and the second insulating part 100.Wire 74 is provided with first end 102, the second end 104.The first insulating part 98 is arranged to be arranged to the second end 104 adjacent to wire 74 adjacent to first end 102, the second insulating parts 100 of wire 74.Wire 74 strides across passage 78, and is used for making the first case member 90 to link to each other with second housing parts 92 electricity.

In the example of sensor unit 62 shown in Figure 4, the first case member 90 and second housing parts 92 can be characterized by separately has first end section 108, second end section 110, and is located at the mid portion 112 between first end section 108 and the second end section 110.The sectional area of first end section 108 and second end section 110 or diameter are less than sectional area or the diameter of mid portion 112.Therefore, the first case member 90 and second housing parts 92 have shoulder 114 separately, and it is used for first end section 108 and second end section 110 are separated with mid portion 112.Entrance 80 and outlet 82 are limited in the first case member 90 and the second housing parts 92 and contiguous shoulder 114, so that passage 78 extends through the mid portion 112 of shell 76.Shoulder 114 is configured as and fluid can be introduced in the entrance 80.

For signal path 75a and 75b are connected on the sensor unit 62, viscometer-densometer 60 also is provided with and is connected to the first terminal 116 on the first case member 90 and is connected to the second terminal 118 on the second housing parts 92.Therefore, signal processor 66 and analysis circuit 68 is communicated with the first terminal 116 and the second terminal 118 by signal path 75a and 75b.Should be noted that signal path 75a and 75b extend through evaluation streamline 46 usually via one or more feedthrough components 120.Feedthrough component 120 provides Fluid Sealing, estimates streamline 46 to allow signal path 75a and 75b to extend through, and prevents from simultaneously that flow from crossing to be formed at the opening of estimating in the streamline 46.

The first terminal 116 can have identical structure and function with the second terminal 118.Can be provided with screwed hole 124 in order to implement the first terminal 116 and the second terminal 118, the first case members 90 and second housing parts 92, it is formed in the first end section 108 or second end section 110 of the first case member 90 and second housing parts 92.In example shown in Figure 5, the first case member 90 and second housing parts 92 are provided with screwed hole 124, and it is formed in the first end section 108 and second end section 110 of the first case member 90 and second housing parts 92.Shown in Fig. 4-6, the first terminal 116 and the second terminal 118 also are provided with threaded fastener 126, are used for each signal path 75a and 75b are connected to the first case member 90 and second housing parts 92.

The first case member 90 and second housing parts 92 link together by any suitable machinery or the assembly of chemical type.As shown in Figure 6, viscometer-densometer 60 is provided with a plurality of threaded fasteners 130 (Fig. 6), is used for the first case member 90 is fastened on second housing parts 92.Should be noted that threaded fastener 130 is made of conductive material such as steel or aluminium usually.In order to prevent that threaded fastener 130 from forming electric pathway between the first case member 90 and second housing parts 92, viscometer-densometer 60 also is provided with a plurality of electric insulation type feedthrough components 132, is used for making a corresponding electric insulation of each threaded fastener 130 and the first case member 90 and second housing parts 92.

The sensor unit 62 of viscometer-densometer 60 can be anchored at by any suitable assembly and estimate in the streamline 46.Should be appreciated that sensor unit 62 should be by anchoring, to prevent from estimating the lengthwise movement in the streamline 46 and to estimate rotatablely moving in the streamline 46.Signal path 75a and 75b preferably have enough rigidity, with prevent sensor unit 62 in estimating streamline 46 lengthwise movement and/or rotatablely move.More anchor device can be used for also preventing that sensor unit 62 is in the 46 interior motions of evaluation streamline.For example, estimating streamline 46 can constriction occur in sensor unit 62 downstreams, to prevent the lengthwise movement of sensor unit 62 in estimating streamline 46.

Those skilled in the art will appreciate that the first case member 90 and second housing parts 92 cooperatively interact when being fixed together by threaded fastener 130, to form connector 72.Wire 74 connects and tensioning as described below.Wire 74 at one end connects.The other end passes the second connector 72, but is not tensioned.The mass body (not shown) is attached on that outstanding on the lax connector 72 end.The size that is suspended in the mass body on the wire 74 that is in the gravitational field has determined the tension force that diameter of wire is suffered, thereby has determined resonant frequency; Can be the resonant frequency that 500 gram mass bodies on 0.1 millimeter the wire obtain about 1kHz by being suspended in diameter.Can change the diameter of wire 74, thereby change range of viscosities to be measured.After through about 24 hours, at the second end clamping wire 74, and take off mass body.This program has alleviated the distortion in the wire 74.Then heat and cool off wire 74, have at the wire of the resonant frequency of quite stable between the thermal cycle each time with formation; For viscometer-densometer 60, in the complex voltage required time of mensuration as the function of the resonant frequency in the about 60 seconds scopes, the resonant frequency of wire 74 must be stable.

In order to calculate viscosity, when having magnetic field, make sinusoidal current pass through wire 74.Magnetic field is perpendicular to wire 74, and can cause wire 74 motions when having sinusoidal current.The induced electromotive force of gained (motion emf) or complex voltage are superimposed upon on the driving voltage.Motion emf can detect by the analysis circuit 68 with signal processor, and signal processor comprises that wherein driving voltage can be offset or place zero lock-in amplifier, perhaps comprises spectrum analyzer.When the frequency of electric current approached or is in fundamental resonance frequency, wire 74 just produced resonance.Complex voltage records in resonant frequency range He under the observation usually, and combines with arithmetic expression, wire density and radius, with the viscosity for the fluid of determining known density.Current strength depends on the viscosity of fluid, and can change, and therefore can utilize detecting circuit to realize acceptable signal-to-interference ratio; Usually adopt the current value less than 35mA, the complex electromotive force emf of gained is some microvolts.Except current strength, the diameter of wire 74 has also been determined upper limit work viscosity; Increase diameter of wire and then can increase upper limit work viscosity.Also there is the alternate manner of excitation and detection wire electromotive force, but all do not have lock-in amplifier convenient like this.

In order to calculate viscosity and the density of fluid from the feedback that comes from wire 74 that receives, analysis circuit 68 operates as described below.Wire 74 is placed in the magnetic field, and driven in the mode of stable state swaying by logical upper alternating current.The voltage V that is distributed on the wire of gained comprises two components:

V＝V ₁+V ₂ (1)

First V ₁Electrical impedance by fixing cord produces simply, and second V ₂Produced V by the electromotive force in the wire when having magnetic field ₁Be expressed from the next:

V ₁＝a+i(b+cf)， (2)

In equation (2), f is the frequency when wire drives when having magnetic field, and a, b and c are adjustable parameters, return to determine by result of the test.Resistance in parameter a, b and the c explanation wire, and absorb used deviation in the lock-in amplifier, to guarantee detectable voltage signals in the sensitiveest scope.Second component V ₂Arithmetic expression by instrument provides:

$V_2=\frac{\mathrm{\Λ}{f}_1}{f_0^2-(1+\mathrm{\β})f^2+({\mathrm{\β}}^{\′}+2{\mathrm{\Δ}}_0)f^{2}i}.---\left(3\right)$

In equation (3), Λ is amplitude, f ₀The resonant frequency of the wire in the vacuum, Δ ₀Be the internal damping of wire, β is the fluid that is moved by wire and the increase quality that produces, and β ' is the damping that causes because of fluid viscosity.

The hydrodynamics of the increase quality of announcement fluid, the vibration wire of β viscous drag β ' can be provided by following formula:

$\mathrm{\β}=k\frac{\mathrm{\ρ}}{{\mathrm{\ρ}}_s},---\left(4\right)$

${\mathrm{\β}}^{\′}=k^{\′}\frac{\mathrm{\ρ}}{{\mathrm{\ρ}}_s^{\′}},---\left(5\right)$

Wherein, k and k ' are provided by following formula:

In equation (6) and (7), A is the complexor that is provided by following formula:

$A=i\{1+\frac{{2K}_1\left(\sqrt{\mathrm{\Ωi}}\right)}{\sqrt{\mathrm{\Ωi}}{K}_0\left(\sqrt{\mathrm{\Ωi}}\right)}\},---\left(8\right)$

Wherein

$\mathrm{\Ω}=\frac{\mathrm{\ω\ρ}{R}^2}{\mathrm{\η}}.---\left(9\right)$

In equation (8), K ₀And K ₁Be amended Bessel function, Ω relates to Reynolds number, and it can characterize the fluid around cylindrical conductor or the radius R.In equation (9), fluid viscosity and density are represented by η and ρ respectively.Therefore, can be by regulating these numerical value, so that the in-phase voltage of predicting from equation (1) to (9) and quadrature voltage are determined viscosity and the density of fluid with consistent by testing the numerical value that records as the function of frequency.The data of collecting in frequency range are typically about f _r± 5g, wherein g is the resonance curve half-breadth, f _rIt is the transverse resonance fundamental frequency.In desirable electric installation, wherein signal to noise ratio is large and be zero with the electrical cross talk that frequency increases, and at this moment, the selection of bandwidth is unimportant.Yet, importantly, as Q{=f/ (2g) } and during unified when tending to bandwidth to occur and increasing (increasing with frequency), unless drive current increases, otherwise corresponding signal to noise ratio is with regard to decline; The importance of determining the bandwidth measure thereon is from hereinafter can be clear.

Equation (4) to (9) obtains by following hypothesis: Comparatively speaking the radius of (1) wire 74 and the length of wire 74 less, (2) compressibility of fluid can be left in the basket, (3) comprise the radius of shell 76 of fluid greater than the radius of wire, so that boundary effect can be left in the basket; And the amplitude of (4) vibration is less.In the viscometer of the vibration wire type of reporting in the literature, resonant frequency to the tension force of wire with and the density ratio of surrounding fluid responsive; Usually by installing mass body in order to cause therefrom the effect of Archimedes' principle at the top clamping wire and in the lower end, increase this sensitiveness to density.Yet if density is recorded by alternate source such as state equation, it is stable only needing the resonance line width.

Generally speaking, the viscometer of vibration wire type, for example viscometer-densometer 60 is absolute devices, does not namely need in theory to record the calibration constant.Yet in practice, some physical property of wire 74 such as density and radius can't come enough accurately to measure by independent method, and therefore, these performances are measured by calibration usually.For this reason, measure in the known fluid of viscosity and density in a vacuum and therein.Produced in a vacuum Δ ₀The wire radius R is to carry out required unique other known variables of viscosity measurement.The wire radius can be determined in one-shot measurement under the prerequisite of the viscosity of given calibrating fluid and density.

1. the modification of arithmetic expression

The complex voltage V that occurs at wire 74 comprises that origin comes from the V of the resistance of wire 74 ₁The V that produces and when having magnetic field, produced by the electromotive force in the wire ₂(equation 1).Except the contribution that comes from resistance, V ₁Also the coupling by background noise such as electrical cross talk or other form is caused.These interference cause the smoother background near the frequency interval the resonant frequency of vibration wire 74.In order to copy fully the measured complex voltage as the function of frequency, in equation (2), comprise other and parameter frequency dependence, that is:

V ₁＝a+bf+i(c+df). (10)

In equation (10), do not consider under the prerequisite of item of other frequency dependence, measured complex voltage usually not can with preferably match of arithmetic expression, therefore will cause the larger error of fluid density and viscosity.This is especially true under the situation of the fluid of high viscosity.

2. determine fluid density and viscosity by the wire of vibration

Fluid density and viscosity is the data of arithmetic expression match of provisioning request and vibration wire 74 really.Least square fitting is based on such concept, that is, the best of one group of data sign can make square sum minimum from the deviation of the data of model of fit (exclusive disjunction formula).Square sum of deviation be called card side (or x ²) goodness of fit statistics closely related.

${\mathrm{\χ}}^2=\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{|D\left(f_i\right)-V\left(f_i\right)|}^2}{v},---\left(11\right)$

Wherein, f _iFrequency index, D (f _i) and V (f _i) be respectively the telegram in reply pressing arithmetic expression of record, v is the degree of freedom quantity for a match N data point.The side's of card standard comprises fluid density and viscosity take equation expression as measuring unknown parameter, in order to make the card side's measured value that limits in the equation (11) minimum, namely

$\underset{\mathrm{\ρ},\mathrm{\η},f_0,\mathrm{\Λ},a,b,c,d}{\min }{\mathrm{\χ}}^2,---\left(12\right)$

Wherein, " ρ ", " η " " f ₀", " Λ ", " a ", " b ", " c " and " d " be unknown parameter.Levenberg-Marquardt algorithm [14] provides non-linear regression, in order to solve this minimization problem.

In all unknown parameters, the amplitude of vibration (being Λ) and the constant relevant with the resistance of fixing cord and other ambient interferences (being a, b, c and d) can be determined well by the minimization program.Yet, at density, viscosity and f ₀In basic uncertainty stoped match itself to pick out correct density and viscosity.This substantially uncertain in order to eliminate, density, viscosity and f ₀In other relation as the constraints in the fit procedure.On mathematics, the relation between these variablees can be expressed by following general formula.

G(ρ，η，f ₀)＝0. (13)

Perhaps, this relation also can comprise other measured value, for example the half-breadth of resonance (g) and the resonant frequency (f that can draw from data _r).

H(ρ，η，f ₀，g，f _r)＝0. (14)

Equation (13)-(14) can tentatively be set up by calibration procedure, perhaps set up by rule of thumb based on field data.The preferred embodiment here is the particular condition of equation (13)-(14); Particularly, hyperplane is by fixing f ₀Limit.Specific descriptions are seen the people such as Restina (Restina, T.; Richardson, S.M.; Wakeham, W.A.; Applied Scientific Research, 1987,43,325-346; And Restina, T.; Richardson, S.M.; Wakeham, W.A., 1986,43,127-158), f ₀Can be appointed as the resonant frequency of the wire 74 in the vacuum, its directly be applied to wire 74 on tension force relevant.If f ₀Be known or given, then just minimum value research be limited to fixedly f ₀On the hyperplane that limits.

Fig. 7 A has shown the flow process Figure 134 that is used for calculating simultaneously as described above viscosity and density.At first, shown in piece 134a, 134b and 134c, with constant such as diameter of wire, wire density and the internal damping factor; Fluid density, viscosity and resonant frequency f ₀Initial estimate; And constraints G (density, viscosity and resonant frequency f ₀) be input among the computing block 134d.Then the represented initial wire response of computing block 134d.This initial wire response can be calculated in in-phase voltage and quadrature voltage.

Then receive the input data, for example as in-phase voltage and the quadrature voltage of the function of frequency, shown in piece 134e, then come computer card side according to the difference of the response of calculating shown in these data and the piece 134f.Then, receive fluid density, viscosity and resonant frequency, the renewal of the estimated value of λ, a, b, c and d.Can adopt any nonlinear regression analysis that the renewal shown in the piece 134g is provided.Then analysis circuit 68 uses Convergence test (such as piece 134h) expression based on the renewal of card side and estimated value.If but Convergence test shows convergence predetermined or receiving amount, then program branches is to step 134i, here output stream bulk density and viscosity.Yet, if Convergence test represents to restrain the predetermined amount that exceeded, then program is got back to step 134d, here, recomputate the wire response based on fluid density, viscosity and the resonant frequency upgraded, and repeating step 134d, 134e, 134f, 134g and 134h are in the predetermined amount until Convergence test shows convergence.

Fig. 7 B has shown the flow process Figure 136 that is used for calculating simultaneously viscosity and density, and the mode among its mode and the above-mentioned Fig. 7 A is basic identical, and difference is as follows.Should be noted that for the sake of clarity the step shown in Fig. 7 A that is equal among Fig. 7 B has identical label.

In the process that is used for calculating viscosity and density shown in Fig. 7 B, testing sensor unit 62 is in order to determine resonant frequency f ₀For calibrating sensors unit 62, sensor unit 62 is put into the environmental chamber with known fluid, then change temperature and pressure to obtain calibration data.Then with in the analysis circuit 68 shown in these calibration data input blocks 136b, and utilize these calibration data to come the resonant frequency f shown in the computing block 136c ₀

Fig. 8 has shown fixing f ₀Hyperplane is handed over the figure of the card side's performance face that cuts, and wherein has global minimum.This figure comprises axis F, D and V.The F axis represents frequency f ₀(Hz).The D axis represents the fluid density (kilograms per cubic meter) around the wire 74.The V axis represents the fluid viscosity (cp) around the wire 74.The meaning of shade refers to the value of card side, and black represents less chi-square value.The position of minimum 137 provides the estimated value of density and viscosity.

If f ₀Be stable and known its ± error range of 1Hz in, then fluid density can record in the error range of 3-4% for the fluid of relative broad range.For the fluid of high viscosity, error is less than 1-2%.If f ₀Known in the error range of ± 0.5Hz, then density error just can be reduced to about 1-2% for the fluid of relative broad range.If f ₀In the error range of ± 1Hz, then the viscosity error is usually less than density error (about 3%).Equally, the viscosity error is also less for high-viscosity fluid.In order side by side to estimate fluid density and viscosity, preferred embodiment requires sensor unit forming frequency oscillator, is used for providing under the temperature and pressure of relative broad range stable and predictable f ₀Representative temperature in the subsurface environment and pressure are about 50 to 200 degrees centigrade and 2.07 to 172.4MPa (300 to 25000psi).

In Fig. 9, shown the sensor unit 150 that is used for another pattern of viscometer-densometer 60.Following described in more detail, sensor unit 150 is similar to the sensor unit 62 at structure and function, difference is, sensor unit 150 is provided with a pair of by the stream of the insulation around the wire 156 pipe 154 Elecrical connectors that separate 152, but not the first case member 90 and second housing parts 92 with the conduction of separating by the insulating layer 96 that extends in parallel.Sensor unit 150 will be described in further detail.

Sensor unit 150 has formed and has been used for providing stable and predictable f ₀Frequency oscillator so that at least two different parameters, for example sensor unit 150 density and the viscosity that immerse fluid wherein can side by side calculate from the data that sensor unit 150 generates.

For the sake of clarity, connector 152 represents by label 152a and 152b in Fig. 9.Connector 152 is identical at structure with function.Therefore, only introduce hereinafter sensor 152a.Sensor 152a is provided with clamp member 158, clamping plate 160, and at least one securing member 162 that clamping plate 160 is fastened on the clamp member 158.Clamp member 158 is connected on the stream pipe 154 by any suitable assembly that matches.For example, as shown in Figure 9, clamp member 158 is provided with end supports 166, and its predetermined portions with stream pipe 154 matches, so that end supports 166 is supported by stream pipe 154.In pattern shown in Figure 9, stream pipe 154 is provided with neck down portions 168, and end supports 166 defines the axle collar that is positioned on the neck down portions 168.Clamp member 158 also is provided with flange 170, and it is connected on the end supports 166 and therefrom extends.For with wire 156 centering on flange 170, be provided with at least one alignment pin 174 at flange 170.As required, clamp member 158 is provided with at least two isolated alignment pins 174, so that wire 156 can be tightened between the alignment pin 174 as illustrated in fig. 9.

Securing member 162 is connected to clamping plate 160 on the clamp member 158, in order to wire 156 is clamped thereon.Securing member 162 can be the utensil on the clamping plate 160 of clamp member 158 can being connected to of any type.For example, securing member 162 can be screw.

Stream pipe 154 preferably is made of the material that has with the similar coefficient of thermal expansion of wire 156.When wire 156 was made of tungsten, stream pipe 154 can be made of such as Shapal-M pottery.

In clamp member 158, formed at least one and opened 180, in order to allow fluid to go out inflow pipe 154 by opening 180.As shown in Figure 9, clamp member 158 can be provided with at least two openings 180, and wherein each opening 180 has semicircular shape.Yet, should be appreciated that the shape of opening 180 can change according to designer's needs.More specifically, should be appreciated that opening 180 can have asymmetric, symmetrical or design shape out.

Wire 156 is to consist of with the similar mode of above-mentioned wire 74.Wire 156 is supported and tensioning in stream pipe 154, and its mode is similar to wire 74 and is supported and tensioning in shell 76.The signal path 75a and the 75b that come from signal processor 66 and analysis circuit 68 are connected on the corresponding connector 152 in any suitable manner, for example screw, bolt, terminal, etc.

As mentioned above, if the resonant frequency f of sensor unit 150 under the vacuum state of equation (1) ₀Be stable, so just can from the complex voltage of measured function as resonant frequency, determine density and viscosity.Because sensor unit 150 comprises two metal connectors 152, it separates by the stream pipe 154 that electrically insulating material forms; Therefore, these materials have different elasticity, in some cases, also have different hot propertys.Connector 152 and stream pipe 154 preferably keep together by the tension force of wire 156 individually.

Sensor unit 150 preferably has the f that is not subjected to fluid property and pressure influence ₀Pressure can have and comes from the compressible less but part that can the calculate contribution of conductor material.In addition, the response of 156 pairs of variations in temperature of wire should be that can survey or computable, and variations in temperature has comprised the caused different heat expansion of different materials that has consisted of resonator because having adopted.When having vertical magnetic field, by making electric current pass through wire, and make wire 156 tensionings and be under the transverse movement.These factors mean sensor unit 150 can by eliminate wire 156 rotatablely move improved, this rotatablely moving may derive from the wire 156 with oval cross section, and sensor unit 150 also must with each end electric insulation of wire 156, flow through it to allow electric current.

Although have certain surface roughness, tungsten remains for to relating to the used preferred material of wire that liquid measures 156, because the young's modulus of elasticity E of tungsten (being approximately 411GPa) and density p _s(being approximately 19300 kilograms per cubic meter) is higher for other material.When wire 156 tensioning, young's modulus of elasticity helps the resonance that provides stable, and density provides the sensitivity to its surrounding fluid, and this is by the ratio ρ in equation (4) and (5)/ρ _sRealize.If amplitude is less and Reynolds number less than 100, then the impact of surface roughness can be ignored.For density measurement, need wire density to trend towards the density of fluid; This derives from the principle of the quality of increase.Therefore, can use tungsten, but according to the expection density of fluid to be measured, more low-density other material also is acceptable.

In order to reduce the impact of thermal dilation difference, the selection of conductor material has been specified the material that is used for connector 152, stream pipe 154 and strainer.More satisfactory is that the mechanical performance that forms the electrically insulating material of stream pipe 154 approaches the mechanical performance of the material that is used for wire 156 and connector 152 as far as possible.For example, can be by selecting the thermal linear expansion coefficient material identical with tungsten, when temperature departure environment temperature thermal dilation difference is reduced the impact of wire tensioning; Shapal-M for example, it is the machinable pottery of high heat conductance with 1GPa compressive strength, the dL/dT=5.210 of and its thermal linear expansion coefficient α=(1/L) ^-6K ^-1(when T=298K), and α (W, 298K)=4.510 ^-6K ^-1The candidate materials that is used for insulation materials can comprise aluminium nitride or Macor, yet the α of these materials also is not equal to the α of tungsten (W).

Standard described in the above paragraph is used for determining the sensor unit 200 that is used for Figure 11 and vibration wire type viscometer-densometer 60 shown in Figure 12 of another pattern, is used for reducing the f that Yin Wendu, pressure and fluid property cause ₀ Variation.Sensor unit 200 is similar to sensor unit 150 in textural and function, difference is, by mainly consisting of sensor unit 200 by having identical thermal expansion and flexible same material such as tungsten, reduce the impact of temperature and pressure, this has also reduced the rotation of wire 156, with reduce because of fluid property change cause to f ₀ Impact.Sensor unit 200 shown in Figure 11 comprises two by the connector 204 and 206 of tungsten formation, and is located at the stream pipe 208 that is used for keeping therein wire 202 between connector 204 and 206.Wire 202 is rigidly connected on each connector 204 and 206.For example, in Figure 11 and example shown in Figure 12, wire 202 electron beam weldings (EBW) are on each connector 204 and 206.

Connector 204 comprises protuberance 212 and end piece 214.Protuberance 212 is connected on the wire 202, and is designed to stop wire 202 rotations.For example, protuberance 212 can have non-circular cross section, and for example the square-section rotates to stop wire 202.Protuberance 212 is located in the cavity that is formed in the end piece 214.Protuberance 212 is configured as and helps and the aiming at of connector 206.Protuberance 212 can form any suitable shape, be used for to help and the aiming at of connector 206.For example, protuberance 212 can comprise taper and conical end, aims at connector 206 in order to help.Wire 202 can be connected on the protuberance 212 by any suitable means, and this means can be rigidly fixed to wire 202 on the protuberance 212.For example, wire 202 can be located in the slit (not shown) that is formed in the protuberance 212 and carry out as described above electron beam welding, so that protuberance 212 has formed the clamp around wire 202.

Connector 206 is provided with end installation portion 216, protuberance 218, insulating part 220 and adjusting part 222, is used for regulating the relative position of protuberance 218 and end installation portion 216.Protuberance 218 is to be connected to the identical mode of mode on the wire 202 with protuberance 212 and be connected on the wire 202.Protuberance 218 is designed to stop the rotation of wire.For example, protuberance 218 can be provided with non-circular cross section, and for example the square-section rotates to stop wire 202.Protuberance 218 is located in the cavity 224 that is formed in the end piece 216.

Insulating part 220 provides the electric insulation between end piece 216 and the protuberance 218.In Figure 11 and embodiment shown in Figure 12, insulating part 220 forms sleeve, on the cavity 224 of its lining in end piece 216, and the face 226 of extend through end piece 216.Insulating part 220 can be formed by any insulation materials that can tolerate subsurface environment.For example, insulating part 220 can be made of ceramic materials such as Shapal-M.

Adjusting part 222 can be any device that can regulate the relative position between protuberance 212 and the end piece 216, in order to allow to regulate the tension force in the wire 202.For example, adjusting part 222 can comprise wire tensioning nut 230, and it is screwed on the protuberance 212.Certainly, many other settings also can be used for wire 202 is clamped on the shell to allow the tensioning of wire 202.For example, with wire clamp shown in two clamp member or connector between, perhaps use spring.

As mentioned above, the vibration wire 74 of tensioning, 156 or 202 need to have the resonant frequency more stable with respect to temperature, pressure and fluid.Stable resonant frequency has reduced the requirement to constant wire tensioning basically.Although the resonator that the words of merely considering from mechanical angle can construction of stable also can provide by the design of relative measurement another solution.Figure 13 has shown the fragmentary of the down hole 10a of another pattern, it is similar to above-mentioned down hole 10 in textural and function, difference is, downhole tool 10a has two or more viscometer-densometers 60, one of them viscometer-densometer 60 (being called 60a) is located in the fluid of unknown viscosity and density, and another viscometer-densometer 60 (being called 60b) is located in the fluid of known-viscosity and density.Each viscometer- densometer 60a and 60b are equipped with magnet 64a, 64b.In this mode, used two similar sensor unit 250a and 250b, one of them sensor unit immerses in the fluid of unknown performance such as density and viscosity, and another sensor unit enters in the fluid of known performance.Sensor unit 250a and 250b can be by consisting of for the sensor unit 60,150 or 200 described modes.

Sensor unit 250a is located at and estimates in the streamline 252, and estimating streamline 252 can be above-mentioned evaluation streamline 46, purification streamline 46a or sampler chamber 50.In downhole tool 10a, eight bend 254 is provided, it is communicated with streamline 252 fluids.Joint 254 defines the comparison chamber 255 of wherein placing known fluid and sensor unit 250b.Downhole tool 10a is provided with pressure equalizing assembly 256, is used for the pressure in the balance evaluation streamline 252.In general, pressure equalizing assembly 256 can be any device of can balance estimating the pressure between streamline 252 and the comparison chamber 255.For example, as shown in figure 13, pressure equalizing assembly 256 can comprise reciprocating-piston 258, and they can be with respect to relatively chamber 255 motions, so that equilibrium pressure.

Sensor unit 250a and 250b are connected on one or more signal processors 260 and the analysis circuit 262, and be used for providing driving voltage and be used for determining one or more fluid parameters, for example viscosity and density, as mentioned above.Signal processor 260 and analysis circuit 262 are similar to above-mentioned signal processor 66 and analysis circuit 68 with function in configuration.

Resonance ratio between sensor unit 250a and the 250b is for example determined shown in Figure 14 A and 14B.Figure 14 A has shown processing 170, is used for utilizing viscometer shown in Figure 13- densometer 60a and 60b to come density and the viscosity of Fluid Computation.Process 170 and have the step similar with above-mentioned Fig. 7 A.For the sake of clarity, similarly step is just put on identical label 134a, 134b, 134d, 134e, 134f, 134g, 134h and 134I, and no longer repeats to introduce.

In general, relatively density and the viscosity of the fluid in the chamber 255 are determined by known method, for example utilize the table that comes from American National Standard technical research institute (NIST) to determine, shown in step 172 and 174.Analysis circuit 262 receives the signal (step 176) from sensor unit 250b, and then known density and the viscosity of the fluid in the chamber 255 are calculated resonant frequency (step 178) based on the comparison.Then analysis circuit 262 calculates viscosity and density by the mode shown in Fig. 7 A.

Shown among Figure 14 B for the another kind of the fluid density of calculating the unknown fluid in the streamline 252 and viscosity and processed 180.Processing in 180, in the initial estimate input analysis circuit 262 with fluid density, viscosity and λ, a, b, c and d, shown in piece 182 and 183.In constant such as diameter of wire, wire density and internal damping factor input analysis circuit 262, shown in piece 184.With other input value, in the temperature and pressure input analysis circuit 262 that is in the sensor unit 250a in the streamline 252 that for example exposes, shown in piece 186.Then from sensor unit 250a and 250b, read input data, for example in-phase data and orthogonal data (piece 188 and 190), and the joint inversion of calculating the data that come from sensor 250a and 250b, shown in piece 183.Analysis circuit 262 is fluid density and the viscosity of output transducer unit 250a fluid on every side then, shown in piece 192.

Although be used for to calculate above two kinds of methods of viscosity and density as mentioned above, yet should be appreciated that any mode of can sampling, ratio measure is carried out in the output that for example two sensor unit 250a and 250b is produced.

If the interior wire of sensor unit 250a and 250b has similar structure (being preferably identical structure), and be exposed under the identical temperature and pressure, just eliminate any unstability that derives from these variablees, thereby obtained representing the data of stabilized oscillator.If these two kinds of designs are combined, namely as mentioned above for sensor unit 250a and 250b relatively or ratio measure and stable geometry, resonator just can be stable so, and density and viscosity can be provided simultaneously.

Be appreciated that from the above description under the prerequisite that does not break away from true spirit of the present invention, can carry out various modifications and variations to the preferred embodiments of the present invention and alternative.Can the artificially and/or automatically start the included device of this paper, in order to carry out required operation.This startup can be as required and/or is carried out based on the data that produce, the state that detects and/or the analytical structure that derives from downhole operations.

The description of this paper should not be considered as having limited significance just for illustrative purpose.Scope of the present invention should limit by a language by claims.Term in the claim " comprises " and means " comprising at least ", so the parts of quoting in the claim are open groups.The term of " one ", " one " and other odd number is intended to comprise its plural form, unless specific eliminating is arranged.

Claims (21)

1. the viscometer that is used for can be positioned on the downhole tool of the pit shaft that penetrates subterranean strata-densometer device, described downhole tool is suitable for the Fluid Transport in the described rock stratum of at least a portion to described viscometer-densometer device, and described viscometer-densometer device comprises:

Can be located at the sensor unit in the described downhole tool, described sensor unit comprises:

At least two connectors that spatially arrange;

Wire, be suspended on to described wire tensioning between described at least two connectors, so that be located in the described downhole tool and described downhole tool is located in the described subterranean strata and when accepting to come from the fluid of described subterranean strata when described viscometer-densometer device, described wire can be used for and described fluid interaction, and described connector and wire configurations are for providing frequency oscillator; With

At least one magnet, described at least one magnet send and the interactional magnetic field of described wire; And

Described viscometer-densometer device also comprises the analysis circuit that comes from the feedback of described wire for reception, is used at least two parameters of calculating and the interactional fluid of described wire.

2. viscometer according to claim 1-densometer device is characterized in that, described connector and wire are made of one type material.

3. viscometer according to claim 1-densometer device is characterized in that, described viscometer-densometer device also comprises be used to preventing the device of described wire with respect to described connector rotation.

4. viscometer according to claim 3-densometer device is characterized in that, described device be used to preventing described wire rotation also comprises the protuberance that is connected on the described wire, and described protuberance has non-circular cross section.

5. viscometer according to claim 1-densometer device is characterized in that, described two parameters are viscosity and density.

6. viscometer according to claim 1-densometer device is characterized in that, described connector is made of the material with similar coefficient of thermal expansion with wire, so that frequency oscillator to be provided.

7. viscometer according to claim 1-densometer device is characterized in that, described viscometer-densometer device also comprises the stream pipe, and wherein, described wire is suspended in the described stream pipe by the described connector that separates by described stream pipe; Wherein, described stream pipe, connector and wire are made of the material with similar coefficient of thermal expansion, so that frequency oscillator to be provided.

8. one kind can be located at the interior downhole tool of pit shaft, and described pit shaft has wall and penetrated subterranean strata, and described rock stratum has the fluid that is contained in wherein, and described downhole tool comprises:

Shell, it has sealed at least one and has estimated cavity;

Fluid is communicated with device, described fluid is communicated with device and can stretches out from described shell, in order to engage with the wall of described pit shaft is sealed, described fluid is communicated with device and has at least one entrance, it is connected with described evaluation cavity, be used for accepting the fluid from described rock stratum, and described fluid is stored in the described evaluation cavity; With

Viscometer-densometer device comprises:

Be located at the sensor unit in the described evaluation cavity, described sensor unit comprises:

At least two connectors that spatially arrange;

Wire is suspended between described two connectors to described wire tensioning at least so that described wire can be used in described evaluation cavity in fluid interaction, described connector and wire configurations are for providing frequency oscillator; With at least one magnet, described at least one magnet sends and the interactional magnetic field of described wire; And

Described downhole tool also comprises the analysis circuit that comes from the feedback of described wire for reception, is used at least two parameters of calculating and the interactional fluid of described wire.

9. downhole tool according to claim 8 is characterized in that, described connector and wire are made of one type material.

10. downhole tool according to claim 8 is characterized in that, described downhole tool also comprises be used to preventing the device of described wire with respect to described connector rotation.

11. downhole tool according to claim 10 is characterized in that, described device be used to preventing described wire rotation also comprises the protuberance that is connected on the described wire, and described protuberance has non-circular cross section.

12. downhole tool according to claim 8 is characterized in that, described two parameters are viscosity and density.

13. downhole tool according to claim 8 is characterized in that, described connector is made of the material with similar coefficient of thermal expansion with wire, so that frequency oscillator to be provided.

14. downhole tool according to claim 8 is characterized in that, described downhole tool also comprises the stream pipe, and wherein, described wire is suspended in the described stream pipe by the described connector that separates by described stream pipe; Wherein, described stream pipe, connector and wire are made of the material with similar coefficient of thermal expansion, so that frequency oscillator to be provided.

15. downhole tool according to claim 8 is characterized in that, described downhole tool also comprises the comparison chamber, and it has comprised the fluid of known performance, and the down-hole state class in the wherein said relatively chamber is similar to the down-hole state in the described evaluation cavity; Wherein, described downhole tool also is provided with the sensor unit that is in the described relatively chamber, so that described downhole tool comprises a sensor unit in the unknown parameter fluid that is located in the described evaluation cavity, and be located at described another sensor unit that compares in the interior known parameters fluid of chamber.

16. one kind is used for the method that at least two unknown parameters of the unknown fluid in the pit shaft of the rock stratum that wherein has fluid are passed in measurement, wherein, downhole tool is positioned in the described pit shaft, and described downhole tool is suitable for the Fluid Transport in the described rock stratum of at least a portion said method comprising the steps of to viscometer-densometer device:

The fluid connection device of described downhole tool is arranged to engage with the wall of described pit shaft is sealed;

Fluid is extracted out from described rock stratum, and inserted in the interior evaluation cavity of described downhole tool; With

Utilize viscometer-densometer device that the data of the fluid in the described evaluation cavity are carried out data sampling, described viscometer-densometer device has and is located in the described evaluation cavity and is suspended on two wires between the connector, and described wire and described connector structure are for providing frequency oscillator; And

Described method also comprises the step of utilizing sampling obtains in described evaluation cavity data to calculate at least two parameters.

17. method according to claim 16 is characterized in that, described evaluation cavity is streamline.

18. method according to claim 16 is characterized in that, described evaluation cavity is sampler chamber.

19. method according to claim 16 is characterized in that, described at least two parameters comprise viscosity and density.

20. method according to claim 16, it is characterized in that, described method also comprises the step of carrying out data sampling for the known fluid in the chamber relatively, and the known fluid in the described relatively chamber has the temperature and pressure relevant with the temperature and pressure of fluid in the described evaluation cavity.

21. method according to claim 20, it is characterized in that, described method also comprises the data of utilizing the data that gather and gather in the described evaluation cavity from described relatively chamber, calculates the step of at least two parameters of the unknown fluid in the described evaluation cavity.

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