SU1661391A1 - Acoustical vibration modulator - Google Patents

Abstract

This invention relates to the field of automatic control of technological parameters during turbine drilling, and may be. applied to measure mud flow. The goal is to improve the accuracy of measuring the flow rate of drilling fluid from any place in the drill string by means of amplitude-pulse frequency modulation in the spectrum of sound vibration, the source of which is a turbo-drill. The device comprises a housing 1, a resonant chamber 2 made in the form of a hollow cylinder with a hole 3 at the end, a gate 4, a rotor 5, and a stator 6 made in the form of rims with guide elements (blades) for the flow of drilling mud. When the drilling fluid is supplied, the turbo-drill starts to generate a spectrum of sound waves, while the rotor 5 rotates with the resonant chamber 2 and the flap 4 blocks the opening 3. A wave pause is formed in the polyharmonic spectrum of the sound waves of the turbo-drill, which the acoustic receiver perceives as a sequence of pulses whose frequency is proportional to the flow rate drilling mud. 2 Il.

Description

The invention relates to the automatic control of technological parameters during turbine drilling and can be used to measure the flow of drilling fluid from any place in the drill string.

The aim of the invention is to improve the accuracy of measuring the flow rate of drilling fluid from any part of the drill string due to pulse amplitude modulation of the frequency in the sound vibration spectrum, the source of which is a turbo-drill.

Figures 1 and 2 present the proposed modulator.

The modulator includes a housing 1, a resonant chamber 2, made in the form of a hollow cylinder, with an opening 3 at the end, a flap 4, a rotor 5 and a stator 6 mounted between the housing 1 and a resonant chamber 2 on which the rotor 5 is installed between the stator 6 and the flap 4, which is mounted on the housing 1 with the possibility of blocking the opening 3 at the end of the resonant chamber 2, which is made with a cylindrical throat 7 installed inside the resonant chamber 2 under the opening 3, the rotor 5 and the stator 6 are made in the form of rims with guide elements (blades ) 8 for mud flow.

The modulator operates as follows.

In the turbine drilling method, the device is installed above the turbo-drill, when the drilling fluid is supplied, the turbo-drill begins to generate a spectrum of sound vibrations, and the rotor 5 starts to rotate with the resonant chamber 2 and a wave pause is formed in the polyharmonic spectrum of the turbodrill by periodically blocking the aperture 3 with gate 4.

Sound vibrations are perceived by the acoustic receiver in the form of a sequence of pulses, whose frequency is proportional to the number of revolutions of the resonant chamber 2, giving a signal through a pulse analyzer to a recording device, determine the flow rate of the drilling fluid using the formula

 -n, with

where Q is the flow rate of the drilling fluid.

c is the proportionality coefficient;

F is the cross-sectional area of the flow.

n - the number of revolutions of the rotor.

Example. Device dimensions: inner case diameter 165 mm outer

115 mm resonant chamber diameter, 105 mm internal resonant chamber diameter, 350 mm resonant chamber height, F hole area 27 cm, throat height

 mm, the volume of the resonant chamber is 3029 cm3, the natural frequency of the resonant chamber is 921 Hz, the rotation speed of the ZTSSh-195 turbo-drill at a flow rate of 25 l / s of drilling fluid is 590 rpm, the number of blades on a rotary turbine is 24. The formula

15

f

п z 60

where n is the number of revolutions of the shaft of the turbo-drill;

t. - the number of rotor turbine blades;

f is the frequency of the information signal; the frequency of the information signal generated by a turbo-drill equal to 236 Hz is determined. An absorption frequency close to the third harmonic of 944 Hz is taken. The estimate of the fraction of the energy absorbed by the resonator from the total energy is determined by the formula

KY

Wo

where Wn is the vibration energy loss of the resonator;

Wo is full of vibrational energy at the resonant frequency.

In the first approximation, an acoustic resonator can be described as a harmonic oscillator with a resonant frequency fo and a quality factor Q. The time period of an oscillator g with an external influence is determined by the formula

g 1,5Q / fo.

Given the opening time of the opening of the resonant chamber t from the condition T T t, take t 0.2 s. Maximum quality factor of the resonator is equal to

Q fot / 1.5 133.

The upper limit is taken for the quality of the resonator 0 10. The energy loss of the oscillations of the resonator is determined by the formula

Wn

2n: About

WK 0,6WK

(one)

where WK is the maximum resonator energy, WK 2aJtma2fo2, (2)

where m p Fh is the equivalent mass of the resonator;

p is the density of the liquid;

and - amplitude of fluctuations.

If the resonator is excited by an external acoustic field whose harmonic of the resonant frequency has an amplitude ai, then ai and a are related by

The acoustic resonator at the resonant frequency absorbs 76% of the energy from the volume of the sound stream.

The width of the resonance curve Afi, i.e. between the points at which the amplitude is 0.7 of the resonance is determined based on the ratio

Af fo / Q.

(3)

From (1NZ), it is obtained that the resonator can dissipate the energy

Wn 1,2 / oFh (aiQfo l) 2. (four)

This energy is absorbed from the volume V of the fluid.

V

-s-c-,

TO

(five)

where s

cr2

- cross-sectional area of the column;

C is the speed of sound in the drilling fluid, C 1500 m / s;

fo is the resonator frequency;

d is the diameter.

The total vibration energy at the resonant frequency in this volume is determined by the formula

Wo 1p V (r aifo) 2 p 2-;. With ai2fo. (6)

From (5) and (6), the fraction of the energy absorbed by the resonator from the total energy in the volume

To W0

F h Q2 f0

(7)

Tttfc

Substituting the calculated data into the form, that k - 0.76. In this way,

ten

For a reference example, Af 921/10 92 Hz. The selection of the useful signal at the wellhead is carried out by a multichannel pulse amplitude analyzer. AI-1024.

Thus, the proposed modulator makes it possible to determine the flow rate of the drilling fluid at any place in the drill string, moreover, taking into account the pressure on the outburst

pump and drilling depths, you can select the optimal drilling mode and drill bits

25

Claims (1)

Invention Formula A sound vibration modulator, comprising a housing mounted thereon for rotation around its longitudinal axis, a resonant chamber made in the form of a hollow cylinder with a hole in the end, characterized in that, in order to improve the accuracy of flow measurement during turbine drilling, it fitted with a damper rotor and stator installed between the case and the resonant chamber, on which the rotor is installed between the stator and the gate, which is mounted on the case with the possibility of blocking the opening on the end of the resonant chamber, which is made with a cylindrical throat mounted inside the resonant chamber above the hole in the end, the rotor and stator are made in the form of rims with guiding elements for the flow of drilling mud. FIG 2 eight