CN102400670A - Design method for three-dimensional induction logging instrument coil system - Google Patents

Abstract

The invention relates to a design method for a three-dimensional induction logging instrument coil system. The method comprises the following steps of: establishing a coil coordinate system according to a three-dimensional induction electromagnetic field principle, and establishing a coil response relation parameter equation under a right-angle coordinate system so as to perform shape adjustment on coil parameters; additionally arranging a three-dimensional shielding coil between a three-dimensional transmitting coil and a three-dimensional receiving coil to serve as a direct-coupled signal counteracting coil; selecting a constraint condition for a coil system structure; calculating field distribution of the coil system by using a biot-savart law according to design requirements and the constraint condition, establishing response relation from the transmitting coil to the receiving coil and establishing an error function formula; establishing an optimization problem and calculating the coil parameters by using an iterative method; and designing a three-dimensional induction logging instrument probe according to the coil parameters. The method is simple and effective; an actual optimization process comprises limitation of the size of the instrument; and the method can be used for designing a more flexible flat-plate (Rogowski) three-dimensional induction coil system.

Description

A kind of method for designing of three-dimensional induction logging instrument coil array

Technical field

The present invention relates to the method for designing of plate (Rogowski) coil array of a kind of three-dimensional induction logging instrument PCB.

Background technology

In the induction logging field, the key component of three-dimensional induction logging instrument is the probe of instrument, is exactly the structure that transmits and receives coil array for array induction logging.The quality of The coils-array configuration design of multi characterizes what and the quality that apparatus measures collects formation information.The three-dimensional induction logging appearance is handled through 3 mutually perpendicular magnetic-field component information that receiving coil is recorded, and can obtain stratum horizontal resistivity R _hWith vertical resistivity R _v, also can obtain anisotropically two kinds of moisture (oil) saturation ratios of layer model, and information such as stratigraphic dip and tool azimuth.The coil array structure of three-component induction logging system comprises 3 transmitting coil (T _x, T _y, T _z) and 3 receiving coil (R _x, R _y, R _z).These 3 transmitting coils are perpendicular to one another; And the alternating current of emission certain frequency; 3 receiving coils are also vertical each other, and receive formation information, especially the three-dimensional induction logging instrument The coils-array configuration design of multi of all directions; In order to obtain uniformly three-dimensional nine magnetic-field components, carried out a large amount of work.Mainly contain two kinds of methods for designing.It is a kind of that to be based on three coils in axial direction mutually orthogonal; But three-winding is not in the method for designing of same position; Coil array structure patent (US6900640B2) such as the invention of Atlas company; Another kind is based on the three quadrature coil architecture that the three-winding design is formed on same position, such as Schlumberger three-component induction logging instrument coil array structure (US0184304A1).

Summary of the invention

The three-dimensional induction instrument aratus probe parameter that the purpose of this invention is to provide a kind of flexographic plate loop construction design; Instrument probe is with present PCB design three-dimensional induction logging instrument coil array; Realize the orthogonality of three direction coils of three-dimensional induction instrument aratus, from the response characteristic Response Mechanism, the big response signal of getting at the receiving coil two ends that guarantee three-dimensional inductive pick-up; And influence the response signal parameter; Mutual correlation degree carries out the reasonably optimizing parameter and designs the three-dimensional inductive coil series signal maximum that meets with a response, and shielding is offset directly coupling signal to I implementation method.

The method for designing of a kind of three-dimensional induction logging instrument coil array of the present invention, the design procedure of this method is following:

According to receiving Luo-coil is evenly close on a Maranyl plate, and coil turn is that the magnetic linkage of NR receiving coil is:

Φ(t)＝μ ₀I ₁(t)N _RS (1)

In the formula, μ ₀=4 π * 10 ^-7(H/m),

When electric current changes, the induced electromotive force of receiving coil:

$V\left(t\right)=-\frac{\mathrm{d\Φ}}{\mathrm{dt}}=-{\mathrm{\μ}}_0\mathrm{NS}\frac{d{I}_1\left(t\right)}{\mathrm{dt}}---\left(2\right)$

Make M=μ in the formula ₀NS, visible M depends on the loop construction parameter.

Induced-current I ₁(t) pass to alternating current by transmitting coil and produce magnetic field, the space induces eddy current I ₁(t), at transmitting terminal, pass to the alternating current relation of generating an electromagnetic field as follows:

1.X on the direction of principal axis:

Electric field E _Xx=0

$E_{\mathrm{xy}}=\frac{\mathrm{i\&omega;\&mu;<figure-callout\; id="4"\; label="Mz"\; filenames="HSA00000259870100021.png,HSA00000259870100022.png"\; state="\{\{state\}\}">Mz</figure-callout>}}{4\mathrm{\&pi;}{R}^3}{e}^{-\mathrm{ikR}}(1+\mathrm{ikR})---\left(3\right)$

$E_{\mathrm{xz}}=-\frac{\mathrm{i\&omega;\&mu;My}}{4\mathrm{\&pi;}{R}^3}{e}^{-\mathrm{ikR}}(1+\mathrm{ikR})$

2.Y on the direction of principal axis:

Electric field $E_{\mathrm{Yx}}=-\frac{\mathrm{I\&omega;\; \&mu;\; <figure-callout\; id="4"\; label="Mz"\; filenames="HSA00000259870100021.png,HSA00000259870100022.png"\; state="\{\{state\}\}">Mz</figure-callout>}}{4\mathrm{\&pi;}{R}^3}{e}^{-\mathrm{IkR}}(1+\mathrm{IkR})$

E _yy＝0 (4)

$E_{\mathrm{yz}}=\frac{\mathrm{i\&omega;\&mu;<figure-callout\; id="4"\; label="Mx"\; filenames="HSA00000259870100021.png,HSA00000259870100022.png"\; state="\{\{state\}\}">Mx</figure-callout>}}{4\mathrm{\&pi;}{R}^3}{e}^{-\mathrm{ikR}}(1+\mathrm{ikR})$

3.Z on the direction of principal axis:

Electric field $E_{\mathrm{Zx}}=\frac{\mathrm{I\&omega;\; \&mu;\; My}}{4\mathrm{\&pi;}{R}^3}{e}^{-\mathrm{IkR}}[1+\mathrm{IkR}]$

$E_{\mathrm{zy}}=-\frac{\mathrm{i\&omega;\&mu;<figure-callout\; id="4"\; label="Mx"\; filenames="HSA00000259870100021.png,HSA00000259870100022.png"\; state="\{\{state\}\}">Mx</figure-callout>}}{4\mathrm{\&pi;}{R}^3}{e}^{-\mathrm{ikR}}[1+\mathrm{ikR}]---\left(5\right)$

E _zz＝0

In the formula, M=N _TS _T, $k=\sqrt{{\mathrm{\&omega;}}^2\mathrm{\&mu;}(\mathrm{\&epsiv;}+\mathrm{I\&sigma;}/\mathrm{\&omega;})}$

Calculate orthogonal in different directions transmitting terminal of three quadrature coils and receiving terminal at last, in each emission receives at interval, record one 3 * 3 tensor voltage matrix G (x, y, z) _{I, j}

${G(x,y,z)}_{i,j}=\left[\begin{array}{ccc}{V}_{\mathrm{xx}}& V_{\mathrm{xy}}& V_{\mathrm{xz}}\\ V_{\mathrm{yx}}& V_{\mathrm{yy}}& V_{\mathrm{yz}}\\ V_{\mathrm{zx}}& V_{\mathrm{zy}}& V_{\mathrm{zz}}\end{array}\right]---\left(6\right)$

Wherein G (x, y, z) _{I, j}Represent that it is the voltage from the i emission that j accepts, i here and j are the footmarks of three-dimensional matrice.When conductivity=0, k=0 gets straight coupling electromotive force G to its substitution (3) (4) (5) through (2) formula ^m(x, y, z) _{(i, j)}:

${G^m(x,y,z)}_{(i,j)}=\left[\begin{array}{ccc}{v}_{\mathrm{xx}}^m& V_{\mathrm{xy}}^m& V_{\mathrm{xz}}^m\\ V_{\mathrm{yx}}^m& V_{\mathrm{yy}}^m& V_{\mathrm{yz}}^m\\ V_{\mathrm{zx}}^m& V_{\mathrm{zy}}^m& V_{\mathrm{zz}}^m\end{array}\right]---\left(7\right)$

Setting up transmitting coil by (6) (7) formula to the response relation error function of receiving coil is:

f _i(Γ)＝|G(x，y，z)-G _m(x，y，z)| (8)

Description of drawings

Fig. 1 XX coil array overall construction design, emission, reception, shielded coil adopt prints plank frame;

Plate (Rogowski) coil sketch map of the single PCB of Fig. 2;

Fig. 3 three-component array structure coil design flow chart;

The response relation figure of Figure 43 9in 72in array electrical conductivity and voltage;

Two 39in 72in of Fig. 5 array integrated radial geometric factor figure;

Two 39in 72in of Fig. 6 array is the Differential Geometry factor graph radially;

The specific embodiment

Designing requirement target of the present invention, measuring-signal operating frequency: 13kHz/26kHz; Measure minimum signal amplitude :≤100nv; Measure horizontal resistivity (0.5-100ohm-m), vertical resistivity (0.5-100ohm-m);

In the coil array design of three-component array induction logging, how making coil array collect enough formation informations is the problem that The coils-array configuration design of multi is at first considered.

Fig. 1 illustrates schematically that three quadrature coils are the apparatus structure sketch map on the three-component induction logging instrument horizontal component.The design of coil on rational deployment, the especially horizontal direction of three quadrature coil systems.Because the coil on the horizontal component is close to casing wall, its wellbore effect is than component is serious vertically.So it is little that design the time must consider to reduce the wellbore effect of horizontal component.

Fig. 2 shows plate (Rogowski) coil sketch map of the single PCB of three-component induction logging instrument XX coil array, and the ring-type printed wire that on the printed board dual platen, evenly gathers forms and prints board-like coil, replaces the traditional Luo-coil with the lead coiling.In this printed coil, printed wiring had both served as the effect of the little wire turn of traditional Luo-coil, also played the coupling and the transmitting effect of signal.Theoretical research and experiment show, under the prerequisite that does not influence dynamic characteristic, can use the ring-type printed wire to replace the coiling of conventional coil; Printed coil is in sequential series, can effectively improve the signal to noise ratio of receiving coil.Make up the circuit board type coil, as shown in the figure.Expression is with two same printed coils (being called for short along string) in sequential series sketch map.

Fig. 3 shows that the three-component coil array is the practical implementation FB(flow block) of instance; Need need to prove the response signal value that will calculate physical constraint condition lower coil, combine actual design to require to set up error function: f according to the response relation on receiving coil response and the shielded coil again according to above-mentioned theory _i(Γ)=| G (x, y, z)-G _m(x, y, z) | wherein, (z) expression is transmitted into the response G of receiving coil to G for x, y _m(z) expression is transmitted into the response of shielded coil for x, y.Make that the directly coupling signal minimum of offsetting is min:f _i(Γ).The practical implementation step is following:

The first step; (the interior length of side of emitted transverse coil is that hem width is 18mm in the 60mm to given coil initial value size; The interior length of side of receiving coil is that hem width is 5.8mm in the 3.6m), array position 12in, 15in, 21in, 27in, 39in, 72in; Line footpath 0.3mm, initial input parameters such as distance between centers of tracks 0.3mm.

Second step; Through the numerical computations program calculate whether satisfy the instruments design principle promptly

then do not adjust coil turn if do not satisfy; Coil dimension recomputates the M value.

In the 3rd step, judge directly coupling signal f simultaneously _i(Γ)=| G (x, y, z)-G _m(x, y, z) | min:f _i(Γ) whether minimum, receiving coil response signal max:F _i(Γ)=(whether z) maximum, if not rotate back into initial parameter, the adjustment design size offers engineering design if satisfy to G for x, y.

The 4th step, from engineering viewpoint, whether can realize, if can not realize, recomputate design parameters again, parameter is done a fine setting, need combine the engineering size to revise coil parameter at this.

In the 5th step, provide according to engineering and can realize that parameter carries out repeated calculation fine setting parameter, calculated response signal again.At last, obtain the one group of design parameters that can realize with engineering, be final design coil parameter.

It is that the coil parameter of instance is in formation conductivity (the linear basically characteristic of 0.001～1s/m) formation conductivity and voltage signal that Fig. 4 shows with the 39in/72in array.The detected small-signal of instrument actual institute ability is at (s/m) 10 ^-6Promptly receive and lie prostrate the level signal.But hope that surveying formation conductivity is the formation information of 0.01 (s/m), but the result of Theoretical Calculation is (10 ^-6～10 ^-7) order of magnitude, make instrument realize reaching the designing technique index like this.To 39in, the long array XX of 72in prints board-like coil array overall construction design, can know that from theoretical calculation analysis the induced electromotive force of receiving coil mainly receives the number of turn of transmitting coil, receiving coil, shielded coil and the restriction condition of emission source electric current.We must weigh the coil parameter of considering theoretical with actual realizability in actual design process for this reason.Consider the parameter of transmitting coil, and the coil design structure, thereby main purpose is to increase winding inductance quantity and reduce the efficient that the transmitting coil internal resistance improves transmitting coil.Further when transmitting coil can be launched energy effectively, we considered the parameter of receiving coil, up to reaching technical indicator.The position of shielded coil.The purpose of shielded coil is to suppress directly coupling signal in theory, in fact, except suppressing directly coupling signal, also has the effect that radial convergence increases investigation depth and longitudinal focusing raising resolution ratio.The negative consequence of bringing simultaneously is to have increased wellbore effect and intrusion effect.Therefore, the relation between considered focusing power and the negative consequence.It is shown in Figure 4 that coil parameter after the optimization carries out the response relation of formation conductivity and voltage of two coil arrays of 39in72in shown in the simulation analysis.

Fig. 5 Fig. 6 shows that two coil arrays of coil parameter 39in 72in that are primarily aimed at design carry out the response characteristic of analytical instrument, comprise the detection feature analysis of two coil subarrays of one dimension characteristic 39in 72in.Has following characteristic from type subarray one dimension receptance function.

1. there is the bigger skin response influence that becomes in rate response function radially on the in-plane direction near well; Radially integration response is compared the negative contribution of its existence of coaxial radially integration response zone.

2. vertical response function (vertical geometrical factor) has following characteristics:

(1) shape is rough, and is asymmetric;

(2) side lobe attenuation is slow, has very strong country rock effects;

(3) some has high resolution information in the main lobe;

(4) vertical geometrical factor negative peak occurs in the shielded coil position on the in-plane direction.Just explain near the well to have a negative contribution, and along with the different contributions of coil position are also different.

We analyze the one dimension geometrical factor on even stratum through above-mentioned simulation analysis, and we obtain the longitudinal frame of 39in, 72in array, and radial depth of investigetion.Probe response characteristic on the XX direction of three-component subarray (radial characteristics, vertical characteristics) is for example at XX/YY direction radial characteristics investigation depth 39in 2.34m; 72in 4.35m, the radial characteristics maximum value is respectively 0.609,0.340 (1/m) maximum value position and is respectively 2.117,1.556 (1/m) maximum value position respectively at 0.731,1.475 (m) in 0.751,1.350 (m) vertical characteristics maximum value respectively.

Claims (8)

1. three-dimensional induction logging instrument probe coil array structure Design method, it is characterized in that: method step is following:

1) according to three-dimensional induction field principle, sets up the coil coordinate system, under rectangular coordinate system, set up coil response relation parametric equation, enable coil parameter is carried out Adjusting Shape;

2) between three dimensional emission and receiving coil, increase the three-dimensional mask coil, as offsetting the directly coupling signal coil;

3) in the selected constraints of coil architecture;

4) according to the designing requirement constraints, utilize than Ao-Sa and cut down the field distribution that theorem is calculated coil array, set up the response relation of transmitting coil to receiving coil, set up the error function formula;

5) set up optimization problem, utilize the iteration Method coil parameter;

6) design the three-dimensional induction logging instrument probe according to coil parameter.

2. the method for three-dimensional induction logging instrument probe The coils-array configuration design of multi according to claim 1 is characterized in that: set up the coil coordinate system, and under rectangular coordinate system, the coil parameter of limited size of coil and shape.

3. the method for three-dimensional induction logging instrument probe The coils-array configuration design of multi according to claim 1; It is characterized in that: between three dimensional emission and receiving coil, increase shielded coil; Based on three-dimensional orthogonal; Each coil array is mutually orthogonal in twos, sets up the three-dimensional induction coil architecture of a few group pattern structures.

4. the method for three-dimensional induction logging instrument probe The coils-array configuration design of multi according to claim 1 is characterized in that: selected target constraints, and theoretical according to being worth most, the receiving coil response signal is maximum, and directly coupling signal is minimum; According to the orthogonality of coil, two coils in a lateral direction are corresponding each other, calculate so the constrained objective function is got a direction.

5. the method for three-dimensional induction logging instrument probe The coils-array configuration design of multi according to claim 1; It is characterized in that: described according to the designing requirement constraints; Utilization is cut down the field distribution that theorem is calculated coil array than Ao-Sa; Set up the response relation of transmitting coil, set up the error function formula to receiving coil;

f _i(Γ)＝|G(x，y，z)-G _m(x，y，z)| (1)

Wherein, (z) expression is transmitted into the response G of receiving coil to G for x, y _m(z) expression is transmitted into the response of shielded coil for x, y.

6. three-dimensional induction logging instrument probe coil array structure Design method according to claim 1 is characterized in that: set up optimization problem

min:f _i(Γ) (1)

max:F _i(Γ)＝G(x，y，z) (2)

In conjunction with actual engineering design and actual instrumentation structural limitations compute optimal coil parameter.

7. whether three-dimensional induction logging instrument probe coil array structure Design method according to claim 1 is characterized in that: meet design requirement to guarantee certain investigative range of instrument according to three-dimensional induction coil parameter substitution integrated radial geometric factor that obtains and vertical geometrical factor correction.

8. the method for three-dimensional induction logging instrument probe The coils-array configuration design of multi according to claim 1 is characterized in that: according to the three-dimensional induction coil parameter designing instrument probe that obtains, can obtain the three-dimensional induction instrument aratus probe of integral array.

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