CN101182770B - Capacitance-type sensor used for horizontal well moisture percentage measurement - Google Patents

Abstract

The present invention provides a capacitive transducer for measuring the water content of a horizontal well, mainly solving the problem that the prior built-in coaxial capacitive transducer for measuring the water content has low resolution and even is unable to distinguish when measuring in low-flux and high water content horizontal well. The present invention is characterized in that the capacitive transducer includes an internal insulation barrel, a metal internal barrel, an external insulation barrel, a metal external barrel, a baffle ring and a pressure cap which are embedded from inside to the outside in order; the metal internal barrel is arranged in a sealed insulation cavity formed by connecting the baffle ring, the internal insulation barrel and the external insulation barrel; the upper part of the metal internal barrel is connected with a conductor and then sealed so as to lead out an electrical connecting wire insulated from the metal external barrel; a ground lead is also led out from the metal external barrel. The transducer aims at measuring the water content of the horizontal output well within the flux of 100m<3>/d, thus having an excellent resolution within the water content of 0-100 percents, overcoming and compensating the defects of the built-in coaxial capacitive transducer for measuring the water content.

Description

A kind of capacitance type sensor that is used for horizontal well moisture percentage measurement

Technical field:

The present invention relates to be used on a kind of oil field the electric elements of horizontal withdrawal well measurement of water ratio, specifically relate to a kind of capacitance type sensor that is used for horizontal well moisture percentage measurement.

Background technology:

At present, in the horizontal output oil well of low yield, mainly use interpolation type coaxial capacitance measurement of water ratio sensor measurement moisture content, but under low discharge because the profit layering, usually cause its resolution ratio lower, when moisture content 50% is above, then be difficult to resolution.Analyzing its reason is: its sampling room of interpolation type coaxial capacitance measurement of water ratio sensor that uses on the capacitance method water cut meter can be equivalent to a coaxial cylindrical capacitor, the oil gas aqueous mixtures is a dielectric, when oil with water content not simultaneously, the electric capacity of ganged condenser correspondingly changes, and therefore can obtain specific retention by measuring capacitance.The radius of supposing the central electrode of capacitor is r, and the insulating layer radius of parcel electrode is R ₁, the insulation materials relative dielectric constant is ε _R1The radius of capacitor external electrode is R ₂, highly be H.The dielectric constant of the oil water mixture between the internal and external electrode is ε _R2C is an electric capacity, and then the capacitance of columnar capacitor is $C=\frac{2\mathrm{\&pi;}{\mathrm{\&epsiv;}}_0{\mathrm{\&epsiv;}}_{r1}{\mathrm{\&epsiv;}}_{r2}H}{{\mathrm{\&epsiv;}}_{r2}\ln \frac{R_1}{r}+{\mathrm{\&epsiv;}}_{r1}\ln \frac{R_2}{R_1}}$

ε in the formula ₀Be the dielectric constant in the vacuum, ε _R2Be profit mixing dielectric constant.

When sensor is used for horizontal well and measures, when moisture content greater than 50% the time, in fact water be communicated with internal and external electrode as conductor.Electromotive force outside the sampling room equals the electromotive force of surface of insulating layer, and promptly shell and interior interelectrode electric capacity equal the electric capacity between insulating layer, and are constant:

$C=\frac{2\mathrm{\&pi;}{\mathrm{\&epsiv;}}_0{\mathrm{\&epsiv;}}_{r1}H}{\ln \frac{R_1}{r}}$

Following formula explanation C this moment and moisture content are irrelevant, and promptly under the situation of horizontal laminar flow, if moisture content greater than 50%, will make internal and external electrode be communicated with, the method will lose resolution capability.

Summary of the invention:

In order to solve the low or even unresolvable problem of resolution ratio that existing interpolation type coaxial capacitance measurement of water ratio sensor exists when the horizontal borehole measurement of low discharge and high-moisture percentage, the invention provides a kind of capacitance type sensor that is specifically designed to horizontal well moisture percentage measurement, it is 100m that this kind capacitance type sensor is primarily aimed at flow ³/ d can have The better resolution with the measurement of interior horizontal withdrawal well moisture content in moisture content 0-100% scope, can be used for overcoming and remedying the deficiency of interpolation type coaxial capacitance measurement of water ratio sensor.

Technical scheme of the present invention is: this kind is used for the capacitance type sensor of horizontal well moisture percentage measurement, by the interior insulating cylinder that has step, the metal inner core, the external insulation tube, metal outer cylinder, baffle ring and pressure cap are formed, insulating cylinder in wherein said, the metal inner core, the external insulation tube, metal outer cylinder is nested from the inside to the outside successively, described metal inner core is positioned at baffle ring, interior insulating cylinder is connected with the external insulation tube in the sealed insulation chamber of back formation, connect the back sealing and draw an electrode that insulate with metal outer cylinder and be connected lead by doing conductor on the described metal inner core, by drawing an earth lead on the metal outer cylinder.

The present invention has following beneficial effect: the capacitance type sensor good reproducibility that is used for horizontal well moisture percentage measurement, the resolution ratio height of taking such scheme to make, this sensor adopts tubular structure in addition, do not have the choked flow element in the runner, so loss in head is little, the certainty of measurement height.Compare with interpolation type coaxial capacitance measurement of water ratio sensor, the experimental result proof is under level conditions, this kind of capacitance type sensor that is used for horizontal well moisture percentage measurement can be measured moisture content under the profit stratification state mutually in level, and in moisture content 0-100% scope good resolution ratio is arranged all.

Description of drawings:

Fig. 1 is a structure sectional view of the present invention.

Fig. 2 is the structure sectional view of building block metal outer cylinder among the present invention.

Fig. 3 is the structure sectional view of building block external insulation tube among the present invention.

Fig. 4 is the structure sectional view of building block metal inner core among the present invention.

Fig. 5 is the structure sectional view of the interior insulating cylinder of building block among the present invention.

Fig. 6 is the structure sectional view of building block baffle ring among the present invention.

Fig. 7 is a course of work schematic diagram of the present invention.

Fig. 8 is the equipotential surface structure chart of whole water body among the present invention.

Fig. 9 is for after the present invention is applied on the horizontal well multiphase flow measurement condenser type moisture content meter, the graph of a relation of sensor output response and water surface elevation.

Insulating cylinder in the 1-metal outer cylinder among the figure, 2-, 3-metal inner core, 4-external insulation tube, 5-baffle ring, 6-pressure cap.

The specific embodiment:

The invention will be further described below in conjunction with accompanying drawing:

The capacitance type sensor that is used for horizontal well moisture percentage measurement described in the present invention, as shown in Figure 1, form by the interior insulating cylinder 2 that has step, metal inner core 3, external insulation tube 4, metal outer cylinder 1, baffle ring 5 and pressure cap 6, insulating cylinder 2, metal inner core 3, external insulation tube 4, metal outer cylinder 1 are nested from the inside to the outside successively in wherein said, and described metal inner core 3 is positioned at baffle ring 5, insulating cylinder 2 and is connected the sealed insulation chamber of formation afterwards with external insulation tube 4.In addition, connect the back sealing and draw an electrode that insulate with metal outer cylinder 1 and be connected lead by doing conductor on the described metal inner core 3, the purpose of drawing this root lead is to connect the driving source (pulse or square-wave oscillator circuit) that adds, in addition, need be by drawing an earth lead on the metal outer cylinder 1, its purpose is to make metal shell ground connection.

The common scheme that the above-mentioned the present invention of being realizes, found following preference by some experiments:

Be that described metal inner core, metal outer cylinder and pressure cap adopt the wire drawing stainless steel material, be called 2Cr13, described interior insulating cylinder, external insulation tube and baffle ring then adopt polyimides as insulation materials.

Be a proof procedure below, to prove validity of the present invention.

In low production liquid horizontal well, oil/water two-phase fluid is subjected to the effect of gravity under the situation of bottom horizontal flow sheet, and they are with laminar flow.Oil as the lightweight phase will be on the water surface, as shown in Figure 7.Sensor of the present invention is followed successively by inner insulating layer, metal level, insulating outer layer and metal shell from inside to outside.In use, with the earthing of casing, as driving source, to guarantee the insulation of electrode and water simultaneously from the metal level extraction electrode.Because water is the good conductor of electricity under low and medium frequency, the process Zhong Shui of actual measurement with contact, the water of pipe interior will become the equipotentiality body with the ground equipotentiality like this.The external surface of water body is an equipotential surface in the sensor.Figure 8 shows that the structure chart of whole water body in this sensor, the S1 representative be the part that contacts with the sensor inwall.What metal level and shell formed is a complete cylindrical condenser, and its value is a constant, can use formula

(1) calculate:

$C_0=\frac{2\mathrm{\&pi;}{\mathrm{\&epsiv;}}_{1}L}{\ln (R_2/R_1)}---\left(1\right)$

Wherein, R ₂The internal diameter of metal shell, R ₁The external diameter of metal level, ε ₁Be the dielectric constant of outer layer insulation medium, L is the length of sensor.Electric capacity between the external surface of metal level and water is divided into two parts, and a part is metal level and S ₁The electric capacity that forms, can think that it is the part of cylindrical condenser:

$C_1=\frac{\mathrm{\&alpha;}{\mathrm{\&epsiv;}}_{2}L}{\ln (R_1^{\&prime;}/R_0)}---\left(2\right)$

Also available plane-parallel capacitor model approximation calculates its capacitance:

$C_1=\frac{{\mathrm{\&epsiv;}}_{2}A}{R_1^{\&prime;}-R_0}---\left(3\right)$

R ₁The internal diameter of ' metal level, R ₀The internal diameter of inner insulating layer, ε ₂Be the dielectric constant of primary insulation medium, α is S ₁Corresponding central angle, A is S ₁Area.When metal level radius and inner insulating layer radius are more or less the same, or can prove that (2), (3) formula are of equal value under the very thin situation of inner insulating layer.

Another part is metal level and S ₂Between electric capacity, metal level and S ₂Between contain two kinds of insulation materials, oil and inner insulating layer can equivalence be the series connection of two electric capacity.When two capacitances in series, its value is less than the value of any one electric capacity, and is close with less electric capacity.The capacitance of considering this part is less relatively, for the ease of analyzing, can ignore.So just obtained the relation function of sensor response with α:

$C=\frac{2\mathrm{\&pi;}{\mathrm{\&epsiv;}}_{1}L}{\ln (R_2/R_1)}+\frac{\mathrm{\&alpha;}{\mathrm{\&epsiv;}}_{2}L}{\ln (R_1^{\&prime;}/R_0)}---\left(4\right)$

Response and α have good linear relationship.

Moisture content with the relation function of α is

$Y_w=\frac{\mathrm{\&alpha;}-\sin \mathrm{\&alpha;}}{2\mathrm{\&pi;}}---\left(5\right)$

Y _wBe moisture content.Following formula is a monotonically increasing function during α ∈ [0,2 π], and the excursion of moisture content is 0-100%.Be to concern one to one between moisture content and the response as can be seen.

Be the measurement of water ratio effect of condenser type moisture content meter under level conditions of verifying this kind horizontal well multiphase flow measurement, carried out static height method experimental study indoor.Be medium with diesel oil and clear water in the experiment, Instrument sensor be placed horizontally in the container that is full of diesel oil, inject clear water gradually in container, the water surface can raise gradually in the sensor, and promptly moisture content increases; Water is bled off gradually, and the water surface just descends gradually, and promptly moisture content reduces.After Fig. 9 provides the present invention and is applied on the horizontal well multiphase flow measurement condenser type moisture content meter, the graph of a relation of sensor output response and water surface elevation, provided the experimental result of 5 repetitions among the figure, made the sensor of horizontal positioned carry out the transition to full water from full oil gradually, tested 3 times by raising the water surface; Carry out the transition to full oil from full water 2 times, promptly the water surface descends.According to Fig. 9 as can be known the output response (capacitance) of this sensor raise with the water surface and monotonic increase or with the reduction of the water surface single-point reduces, promptly increase or reduce with the reduction of moisture content with the increase of moisture content, have good repeatability.In addition, the experimental result proof is under level conditions, the capacitance type sensor of horizontal well moisture percentage measurement can be measured moisture content under the profit stratification state than interpolation type coaxial capacitance measurement of water ratio sensor in level, and in moisture content 0-100% scope good resolution ratio is arranged all.Put it briefly, good reproducibility, resolution ratio height are the advantages of this kind capacitance type sensor.In addition,, there is not the choked flow element in the runner because this sensor adopts tubular structure, therefore, not fragile.And because the loss in head that produces is little, certainty of measurement is higher.

Claims (3)

1. capacitance type sensor that is used for horizontal well moisture percentage measurement, by the interior insulating cylinder (2) that has step, metal inner core (3), external insulation tube (4), metal outer cylinder (1), baffle ring (5) and pressure cap (6) are formed, insulating cylinder (2) in wherein said, metal inner core (3), external insulation tube (4), metal outer cylinder (1) is nested from the inside to the outside successively, described metal inner core (3) is positioned at baffle ring (5), interior insulating cylinder (2) is connected with external insulation tube (4) in the sealed insulation chamber of back formation, connect the back sealing and draw an electrode that insulate with metal outer cylinder (1) and be connected lead by doing conductor on the described metal inner core (3), by drawing an earth lead on the metal outer cylinder (1).

2. a kind of capacitance type sensor that is used for horizontal well moisture percentage measurement according to claim 1 is characterized in that: described metal inner core (3), metal outer cylinder (1) and pressure cap (6) adopt the wire drawing stainless steel material.

3. a kind of capacitance type sensor that is used for horizontal well moisture percentage measurement according to claim 1 and 2 is characterized in that: insulating cylinder (2), external insulation tube (4) and baffle ring (5) adopt polyimide material in described.

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