SU1305616A1 - Method of acoustical impedance logging of wells - Google Patents

Abstract

The invention relates to well logs and can be used to determine the acoustic impedance of rocks surrounding a well. The invention aims to increase the sensitivity and accuracy of measurements of the acoustic impedance of rocks surrounding a well. The method consists in the excitation of elastic oscillations by a radiator, which oscillates radially in the well with a liquid. To achieve the goal, harmonic elastic oscillations with a fixed amplitude of the oscillatory velocity or sound pressure are excited. The oscillation frequency is changed until a radial resonance of the fluid is achieved. The frequency of the radial resonance of the fluid is measured. The amplitude of sound pressure oscillation or oscillatory velocity at the frequency of the radial resonance of the fluid is measured. The diameter of the well is determined from the frequency of the radial resonance of the fluid. The acoustic impedance of the rocks surrounding the well is determined by the amplitude of the oscillations, the sound pressure or the oscillatory velocity at the frequency of the radial resonance of the fluid and the diameter of the well. The method makes it possible to eliminate the measurement error of the acoustic impedance of rocks due to inaccuracy of the tie-in depth of the obtained data, since taking into account the influence of the borehole diameter on the measured acoustic impedance is performed at each position of the well probe. 1 il. C O Cf Cf: 05

Description

t13

The invention relates to -c / ophr: h1 -, - borehole research k; -1 (): s; be used for .pen ;; acoustic impedance Mr. Orngh,; surround a well

The purpose of the inventive and - iioistitiueaHe m; ..--: conformance to the accuracy of the HSMSpei Hi acoustic impedance of the mountain ;; oi. :); surrounding the well,

The drawing shows schemag. I remove the proposed method

The circuit contains a radial-gb -;:; - emitting emitter 1j oscillator 2 on each of 1i, a fstz measuring instrument 3, a receiver 4 acoustic oscillations and liquids, a frequency meter 5, measuring and amplitudes and acoustic insulators

The proposed method is implemented.); - as follows

- Radiation oscillating in the well; -: ;; emitter with liquid; 1 excitement; kpa:; m liquids elastic harmonic oscillations that are partially emitted; g- the form of diverging waves into an array of or- ganic rocks. Specific acoustic and; - -; ped5.ns Z, the loading radiator, is defined as the ratio of pressure V

in the liquid on the surface: LUCK ;:

r and its radial KOj ;; e6aTej ;; bHOH velocity and is equal to

 -i (p, c) (

Ado (- Bd 00,

Where

  .1, 5 j

fe)

, / g „G.NoS-X-Pr) (n, - 2pr; -r –y -

  3e CJR / C: n ,, L / C. ; C / Cp; g p "/ p

circular frequency of oscillations; radiator radius: well radius;

Cs, - the velocities of the rational waves of the waves of the waves; 5 dc, 5 Grodoll x waves in an elastic medium; n pop - ;; - river waves E elastic spring; lsidkosgi density to yriijv; of environment; Hankel pefvy funk

n-th order from a p uyent xj - functions BeecejJH. n Neumann n-th order of argument X.

from vibrations. And e - with GE -: & - 2 excitement to dos; EH; en -: 1: h

r de K - momra ;; andalnog resonance

liquid layer} | k: ti;

N ;, - rezians; a circular frequency, LL real; and; apn; | the proposed method is sufficient to do with: and - sequence -: Elness c; 11: the radio sets K; - c5bu ;; 13 radial n; 3onance; oa, iipKMPN use.;: Name: -; no low - drink from riHX CO. ld1k; 1uh-g; ate d: 1n toyp / vg and tsp and; 1 I -: accuracy; accuracy. l; at stm m1 from which ir- fnenn; and rooiii.ix iiopcjt ,, :: kgl gkayui their sk; azhinu ) (; c) 6yc: ioi;: ie sc that from to: and; 1 rotted hour oTh; me; g,; e; with an iodine situation. will r. ; y (IDK (h: ti and rocks. iJTO noBi.ii iat; T kindness pa,; J; al - ioro

.BREAKING BONE,

i: pH imb - rieiii-H; ac; colds /; staging: bv oi from the resonance of Y-YAH-atsti is controlled, for example, by a 3 pa 5 ;; с cr phases of the ph | i e ;; -, L — у у-bank fia due 1 and n); -; t; ii ik aKvc gic; 1; their COP lebani z zhpkssty ,.

Frequency 1.; you will measure with frequency meter 3, and oscillation; s - meter 6 amplitude. When the radial1:. Of the fluid is reached, the liquid is recorded with a resistive peak (acTOT - and resonance) amp. the magnitude of the oscillations corresponds to П1№1С: ш, Ьв frequency meter 5 and the measurement is 6 a uLJ t lTyd., Akust; H3OJL4T (; ipbi / g allow for attenuation 5 - ;; oscillate or decrease; -: 1 hectare emitter of the receiver's indication, acoustically; oscillations in; comp. 4) The higher the speed of discharge (), the resonance of the fluid; the TO4tioc b Radiation of the frequency of the radial resonance of the fluid, because it is like at 03 W .;

 -}, -:

 -QH; j - with to

 Tizmetr 1; Kviyeviyy opred (.nchut rto iz-:: yrpniy frequency radical;) re junan-s ;, liquids -Iz of the formula (1, s

UGELAIL ACCESS. impedance

fluid resonance at a fixed amplitude of the oscillatory velocity and borehole diameter using the formula

pcp- k, kj, cO |

one . RN I, (to p

k,

(2)

SlTRLC -

where L is the amplitude of the oscillatory velocity at the frequency of the radial resonance of the liquid k is constant, defined

the design of the acoustic emitter and receiver j TJ is the length of the emitter. From the formula (2) it follows that the larger the amplitude A, the higher the sensitivity of the pcp measurements. The amplitude of oscillations A at the frequency of the radial resonance of the fluid is proportional to the Q of the resonance Qm, therefore the sensitivity of the measurements of the acoustic impedance of the rocks surrounding the well increases Q, times compared with the known method,

In the case of fixing the amplitude of the sound pressure and measuring the amplitude of the oscillatory velocity, formula (2) remains in force, and the inverse of the impedance of the rocks pCp is calculated.

Additional determination of the borehole diameter during the measurement of the specific acoustic impedance of the rocks surrounding the borehole increases the measurement accuracy. In the proposed method, the error is eliminated

measurements of the acoustic impedance of the rocks due to the inaccuracy of the sand in the depth of the data obtained, since taking into account the influence of the well diameter; The measured acoustic 1 mpdance is performed at each position of the borehole probe.

(2)

- W

Form in l

gaining

The method of acoustic impedance logging of wells, involving the excitation of elastic oscillations radially oscillating in the well with a liquid emitter and recording parameters of these oscillations, characterized in that, to increase the sensitivity and accuracy of measurements of the acoustic impedance of the rocks surrounding the well, elastic harmonic oscillations are excited liquids with a fixed amplitude of oscillatory velocity or sound pressure, change the frequency of oscillation until the radial resonance of the fluid is attained For example, the frequency of the radial resonance of the fluid is measured, the amplitude of the sound pressure or oscillatory velocity is measured at the radial resonance frequency of the fluid, the diameter of the well is determined by the frequency of the radial resonance of the fluid, and the amplitude of the oscillation of the sound pressure or oscillation velocity at the frequency of the radial resonance of the fluid and The borehole diameter is determined by the acoustic impedance of the rocks surrounding the well.

Compiled by N.Zhuravishva Editor M.Blanar Tehred L., 0laynik Proofreader L.Patay

1424/43

Tirak 731Subscribe

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushskak nab, 4/5

Production and printing: gdr1, g, Uzhgorod u.g: .Project, 4

Claims (1)

Claim The method of acoustic impedance logging of wells, which consists in exciting elastic vibrations of a radiator radially oscillating in a well with a liquid and recording parameters of these vibrations, characterized in that, in order to increase the sensitivity and accuracy of measurements of the acoustic impedance of the rocks surrounding the well, elastic harmonic vibrations in the fluid are excited with fixed amplitude of the vibrational velocity or sound pressure, change the oscillation frequency until the radial resonance of the liquid , measure the frequency of the radial resonance of the fluid, measure respectively the amplitude of the vibrations of sound pressure or vibrational velocity at the frequency of the radial resonance of the fluid, determine the diameter of the borehole by the frequency of the radial resonance of the fluid, and the amplitude of the sound pressure or vibrational velocity of the frequency of the radial resonance of the fluid and borehole diameter determine the acoustic impedance of the rocks surrounding the well.