SU370568A1 - METHOD OF ACOUSTIC CARROT - Google Patents

Description

one

The invention relates to the field of geophysical methods of loiskav and exploration of mineral deposits and can be used in borehole seismoacoustic studies.

According to the well-known method of continuous high-speed acoustic logging with analogue-registration of measurement results by frequency conversion of informational signals for treating infarmation signals, the following sequence of operations is carried out: shifting the information signal of a duration A / by a certain amount, integrating the delayed pulse and obtaining a sawtooth signal with amplitude A, proportional duration; the selection of the signal from the Orointegrating Pulse equal to the delay; repeated repetition of the delayed pulse of the tra / pezidal shape with the amplitude L.

However, the known method is characterized by low measurement accuracy associated with errors in converting the duration of information sipnals to the amplitude of multiple repetitive pulses due to instability of the delay, inaccuracy of integration, as well as distortion of amplitude A with repeated repetition.

The purpose of the invention is to create a method of acoustic "acoustic", which makes it possible to increase the accuracy of measurement; This is achieved by the fact that

The signals are transformed into start and end pulses, molded into multiple repeated signals, sum these signals and convert their IB sequence of video pulses, and the transformation. Information signals into start and end pulses and the formation of multiple repetitive signals are performed in a single channel. FIG. 1 shows a block diagram of a transformation according to the proposed method; on

FIG. 2 - graphs illustrating the transformation; in fig. 3 is a block diagram of an apparatus implementing the proposed implementation; in fig. 4 - graphs illustrating the operation of the equipment.

The receiver-transducer / receives ultrasonic oscillations propagating through the rock and converts them into electrical impulses that are shifted in time by the value of the measured interval time

, tzu, etc. The pulses follow with a period T of operation of the ultrasonic emitters. Pulses received at the output of receiver-converter 1 are fed to the input of the adder 2. A set of pulses arriving at its input, corresponding to the near and far receivers (emitters) of the acoustic probe, the adder sends to a single-channel driver 3. The shaper converts each pair of pulses received at its input Shifted by the value of the measured time interval, B is a multiple group of pulses of multiplicity 2M, where M is a lolol integer number greater than one, followed by them in all groups with a period of repeat reni. The durations of all the formed groups are the same and do not exceed the repetition period of the ultrasound emitters, i.e. MG T. To extend the measurement dialazon, the Repetition period To is repeated longer than the maximum possible expected duration of the interval propagation of elastic oscillations for the geological section under study.

At the output of the imaging unit 3, multiple groups of pairs of impulses have shifts between the pulses of the beginning and end of each pair, equal to the corresponding interval time iiu measured, etc. Then the signals from the output of the formatel 3 are input to the input of the converter 4, which generates pulses equal to 1ПО the duration of the time shifts between the onset and coils of each pair. From the obtained sequence of pulses in a known manner, using a integrating circuit 5, a constant component is extracted, which is recorded in analog form in the form of a continuous logging curve using the recorder 6. In this case, the time constant of the integrating circuit 5 is reduced in proportion to M compared to the period T, which, due to an increase in the repetition rate of the integrated pulse sequence, does not cause an increase in the pulsation of the detected constant component. The listed conversion sequence is illustrated by the graphs shown in FIG. 2

On fng. 2, a, b show the pulses at the output of the receiver-transformer, corresponding to the beginning and end of the measured time interval. Relative to each other, the pulses are shifted in time by the magnitude of the measured interval tin, tzu n followed by a period T of repetition. FIG. 2, s are shown pulses at the output of the adder, which are a set of pairs of pulses that follow with a period T of repetition. FIG. 2, g shows multiple groups of pairs of pulses at the output of the former. Within the groups, a pair of pulses follow with a repetition period G0, a shift in (the time between the pulses of the beginning and the end of each pair in the pearl is equal to the measured time interval. In Fig. 2, e are shown the pulses at the output of the transducer. The duration of the pulses in each multiple group is the same and equals the time shift between the pulses on the output 1 of the receiver-converter. The number of pulses in the group is equal to M.

The proposed method can be implemented with (by means of the apparatus, the block diagram of which is shown in Fig. 3. The apparatus includes an adder 7, a driver 8 and a converter 9. The adder is a passive sludge active circuit with a common load, the output of which is connected to the driver A single channel driver can be built on the basis of a pulse recirculator. The driver includes a delayed feedback recirculator 10, which is closed via switch 11. The key is controlled by a pulse number counter 12, the input cat cerned coupled to recirculation outlet torus.

The recirculator output is also connected to the converter 9. A trigger can be used as the latter.

The equipment is captured by the graphs shown in FIG. 4. The pulses from the output of the converter receiver, shifted in time by the value of the measured time interval tu (see Fig. 4, a, b), are fed to the adder's input. The resulting pairs of pulses (see Fig. 4, c) are fed to the input of a single channel

shaper. In the initial state, before the filing of the input of the pulse former from the output of the adder, the key is closed. After the first pair of pulses with a shift tiu (see Fig. 4, c) is fed to the recirculator input, a pair of pulses with a TQ repetition period determined by the feedback delay value begin to circulate in the recirculator ring (see Fig. 4, d) . After passing through the ring of the recirculator, the circulation of M pairs of pulses,

The pulse counter 8 generates a signal that, for some time, breaks the feedback circuit with the help of the key 11 (see Fig. 4, d). Thereby, the circulation of pulses around the ring, caused by the arrival of a pair of pulses shifted in time by the measured interval, is stopped. By the arrival of the next pair of pulses shifted in time by tzu, the shaper returns to its original state, then the process of forming multiple pairs of pulses is repeated.

Thus, at the output of the shaper, the pulse sequence consists of M pairs of pulses, which follow with a period of Gu repetition. The duration of multiple pairs is equal to the corresponding measured interval time tm, W and the number of pairs is equal to M.

The generated sequence of pairs of pulses is then fed from the output of the driver to the converter, which converts the time shift between the pulses naip to the duration of the pulses. FIG. 4, e shows the signals at the output of the converter which are a set of multiple groups of rectangular pulses equal in duration to the measured time interval Uu, 4u, etc. The number of pulses in each group is equal to M, the repetition period is T o. The generated pulse train is then fed from the converter output.

at the input of the integrating circuit, with a reduced proportional to M constant time.

Subject invention

Claims (2)

1. Acoustic logging method is used to transform the frequency of information signals, characterized in that, in order to improve measurement accuracy, information The signals are transformed into impulses of the “starters” and “koitsa”, they form “In the form of many times the second signals,” sum these signals and convert them into a sequence of video pulses. 2. A method according to claim 1, characterized in that the conversion of the information signals into start and end pulses and the formation of multiple repetitive signals are performed in one channel. ltrazKukoE koldani 12 -Mpppppppppp ; 2 2m I / 2 M 1 2 FIG. 2 Impulses i bixoffa pr-5raz6atel And Towards the integrating goal AND AND m 1 m