SU661470A1 - Device for measuring attanuation factor of resilient waves in rocks - Google Patents

Description

The 366 oscillations in the mud for the near and far actuators are different, which leads to a significant measurement error, especially when working in a well with a heavy mud, where the energy of elastic oscillations is especially large. The circuit of the invention is to reduce the measurement error of the attenuation coefficient. The delivered circuit is supported by the fact that in the device, which includes a control unit, a detector, a logarithmic signal converter from the near and far radiators, and a subtraction circuit associated with a logarithmic converter, the inputs of the subtraction circuit are additionally connected through a switchboard and a code-converter converter operative zoguminating device, the entry of which is connected to the output of the logarithmic converter, and the address input 1 - to the pulse counter g kill, control the next record about, and to two counters depth readout control pulses. The meters controlling the readout contain the initial stroke setting circuits equal to the ratio of the bases between the Viio H - long. one counter and probe spreading or a long-range radiator - dp other; rn) r6 counter kshagu iypulbsbv depth sensor. : ... .v:.: v. -. ; Fig, 1 shows the structural scheme of the device; in fig. 2 - puree, characterizing the distribution of pulses in the cycle; in fig. 3 g of the borehole tool streaks relative to the borehole wall during its movement in the logging process and show the sections of the propagation path of oscillations from the emitters to the receiver along the drilling mud and rock. The device contains a controlled detector 1, a logarithmic converter 2, onefpaTHBHoe storage device 3, a switched converter 4 number anapog, a switch 5, a subtraction circuit 6, a counter 7, control for writing, counters 8, 9, control read, and block 10. The detector 1 sends an information signal in the form of oscillation packets from the near and far emitters, located at a distance from the receiver at an appropriate distance of 8 H I I and C + E, where 6 is the base between the signals in the detector and is detected and detected n pershlh many branches of each packet. 0 The detected signals of the near and far emitters are fed to the inputs of the logarithmic converter 2, where they are first converted into pulses, the duration of which is proportional to the log pulse of the measured amplitudes, and then the duration of these pulses is converted into a parallel binary code. The conversion cycle starts with the arrival of the next depth pulse. The value of the logarithm of the amplitude of the near-emitter signal recorded in the form of a digital code is decoded by the transducer 4 of the code-analog and, through the switch 5, is fed to the non-inverting input 11 of the subtraction circuit 6 implemented at the operational amplifier. At the same time, input 11 as well as inverting input 12 of the Subtraction Circuit through the same converter code-analogue and switch 5 receive information from random access memory 3, Device 3 is a matrix of static memories on the MOS structures, equipped with a decoder address inputs and write and read circuits and a record connected to a logarithmic input; converter 2, and address inputs through the control unit 10 - with counters, 7-9,. The counters are connected by counting inputs with a depth sensor, the counter code 8 having the initial code Nj equal to the ratio of the base length between the radiators E and the step db of the depth sensor pulses, and the counter code 9 having the initial code Ng, equal to the distance distance probe distance the emitter L to the pulse pitch of the depth sensor. The control unit 10 is synchronized with the clock pulses of the channels of the near and far emitters, as well as with the pulses of the depth sensor and provides the time-. switching and control of device blocks, excluding the mutual overlap of information from different channels and write and read cycles. So, after the depth sensor pulses 13 successively, 6d "after another, follow the commands of the block-ut; direct 10 to form a pulse 14, proportional to the duration of the signal from the near emitter, pulse 15 to record this signal, pulse 16, proportional to the signal duration from the far-emitter, the pulse 17 of the recording of this signal and the read pulses 18-20,

providing readout of information stored by memory 3 using counters 7-9.

Thus, the input 11 the subtractor 6 receives a voltage proportional to the logarithm signal bggazhnego izpuchatep EpIl voltage proportsionatshnoe pagorifmu low emitter E n U signal with a delay corresponding na1chalnomu entry in the counter 9 and to the input 12 receives a voltage proportional to the logarithm of long-range signal: tep pL12 with a delay corresponding to the initial code in counter 9, and a voltage proportional to the logarithm of the signal from the far-emitter 2 P and 2 with a delay corresponding to the initial code in counter 8.

The voltage TJj corresponds to the amplitude of the signal that arrived at the receiver In position 1 of the device and underwent weakening in the drilling fluid in sections A and B and in the breed in section b, i.e.

lf, (A.B) - (Xn-Li, 25 f

 -. where and o is the amplitude of the signal near the cell; Ocr - attenuation coefficient in the drilling solution; о (. п - attenuation coefficient in rocks. Correspondingly, EnUl EnUo-oCp (.B) -oCпL. Thanks to the initial code in counter 8, the value tl | corresponds to the earlier position AND of the wellbore, offset from position I by distance. -. - r. N-ligly 6, i.e. in this case, Di Epi EpIo-Lr (A4.c). Due to the initial code in the counter 9, the values of CG and Ug correspond to an even earlier position of the device 1P; see relative to position T for distance:. N, j-uL-7 - dL 14-6,. . 2. uL i.e. in this case: enu; enUo otp (c + p) -oLnL, enU2 EnUo- (XplD-bB) -oLn (LfB).

The voltage at the output of the device is the output of the whole device;

Calc ((gr7u; .epu; l.

After substitution 1G

2nd,

OUT

those. in the resulting expression dp of the output voltage, there are no terms, where ccp is the attenuation coefficient in the drilling mud. The output voltage is directly proportional to oC n - the attenuation coefficient in the rock.

The use of the proposed device will allow to reduce the measurement error of the attenuation coefficient of rocks by eliminating the influence of the damping of elastic oscillations in the drilling fluid, and, consequently, will increase the reliability of the information obtained by acoustic well logging.

About the Invention of the Invention A device for measuring the attenuation coefficient of elastic waves in roplbix rocks, including a control unit, an amplified detector, a logarithmic converter of signals arriving at the receiver from near and far emitters, a subtraction circuit associated with a logarithmic converter , and the HMnyrtbOoB depth sensor, which differs from the fact that, with a tie, reducing the error caused by the elastic energy of the elastic waves in the drilling mud, a counter that controls the recording, and two counters that control reading them, a quick operating device with a code-analog converter, a switch, while the counters are connected by counting inputs to the depth pulse sensor, the address inputs of the memory device are connected through the padding unit to the outputs of all counters, the write input is with the output of the converter, and the inputs of the circuit are connected the subtractions are additionally connected via a switch and a code-analog converter about the output of the storage device, and the initial codes of the counters controlled by coupling are set equal to scheniyu base between the emitters - for a counter and the distance of the probe distal emitter - for the other counter to step depth sensor pulses,

Sources of information, 1FIN "Tillt into consideration when exprinting

1. US patent N 3270ai (i, кп. 34О-18, 10 "in,

2. M ": ggoiii s.koo guide to the use of oil and gas wells by the anarcharput SPLK-2M, Oct. Brsk, 1974.