RU2476668C1 - Borehole deviation monitoring method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: borehole deviation monitoring method consists in measurement of deflection value of drill pipe or oil well tubing by means of a borehole tool lowered vertically to the well pipe. At that, as a borehole tool, a reversible acoustic transducer with uniform directivity characteristic is used, which operates in the mode of sequence of sounding pulses. Besides, the borehole deviation value is determined as per enlargement of sounding pulses reflected from walls. As sounding acoustic pulses, a sequence of radio pulses of rectangular or bell-shaped form is used.

EFFECT: contactless performance of borehole measurements.

4 cl, 3 dwg

Description

The invention relates to the oil and gas industry and can be used to control the integrity of wells.

A known method of the same purpose, according to which the value of the deflection of the well is determined using a downhole tool, vertically lowered into the drill or tubing of the well (RF Patent No. 2055178, CL ЕВВ 47/00, 1996).

This method is adopted as a prototype.

In the prototype, as the downhole tool, vertically lowered into the tubing, use deflection sensors made in the form of retractable elements arranged in pairs in two mutually perpendicular planes passing through the axis of the device body.

The disadvantage of the prototype is the contact nature of the measurements, which reduces the reliability of the study of the wellbore due to possible breakdown of the downhole tool.

The technical result obtained from the implementation of the invention is to provide contactless measurements carried out in the well using a downhole tool.

This technical result is achieved due to the fact that in the known method of controlling the curvature of the wellbore, which consists in measuring the deflection of the drill or tubing of the well with the help of a downhole tool that is lowered vertically into the wellbore, a reversible acoustic transducer with uniform directional characteristic operating in the sequence of probing pulses, while the magnitude of the deflection of the wellbore is judged by the broadening trazhennyh by probing pulses walls.

As sounding acoustic pulses, a sequence of rectangular or bell-shaped radio pulses is used.

As sounding acoustic radio pulses, a sequence of radio pulses using a duty cycle of 10 is used.

As sounding acoustic pulses, radio pulses of 10 ^-4 s duration are used.

The invention is illustrated by drawings. Figure 1 presents a diagram of a device for implementing the method in various sections of the wellbore; figure 2, 3 is a timing diagram for explaining the operation of the device.

The device contains (Fig. 1) a reversible acoustic transducer (AP1) with a uniform directivity characteristic (XI), operating in the mode of emission and reception of a sequence of acoustic pulses.

AP1, for example, of the piezoelectric type, is mounted on a logging cable 2 kinematically connected with a hoisting device 3 (SPU3).

SPU3 provides the launching (lifting) of AP1 on the logging cable vertically down (up) along the axis of the drill pipe or tubing 4, which the well table is equipped with.

SPU3 is equipped with a depth sensor 5, to which AP1 descends.

The downhole tool includes a relay 6 transmit-receive, the transmitting path 7 and the receiving path 8.

The transmission path 7 includes: a sound (or ultrasonic) frequency generator 9; pulse shaper 10; a modulator 11 and a power amplifier 12.

The receiving path 8 contains: amplifier limiter 13; detector 14; attenuator 15 pulses and computer 16.

Electrical connections between the blocks of the transmitting and receiving paths 7, 8 are presented in figure 1.

The audio frequency generator 9 and the pulse shaper 10 are connected respectively to the main and modulating inputs of the modulator 11, the output of which through the power amplifier 12 is connected to the first contact of the transmit-receive relay 6. The second contact of the transmit-receive relay 6 is connected to the amplifier-limiter 13, and the controlled third contact of the transmit-receive relay 6 is connected via a logging cable 2 to AP1. In addition, the output of the pulse shaper 10 is connected to the control input of the transmit-receive relay 6.

The output of the amplifier-limiter 13 through the detector 14 is connected to the first input of the computer 16, the second and third inputs of which are connected to the outputs of the depth sensor 5 and pulse attenuator 15.

The method of controlling the curvature of the wellbore is implemented on the device (figure 1) of the same purpose as follows.

The sound frequency generator 9 generates a continuous harmonic signal of sound or ultrasonic frequency, for example, 100 KHz, and the shaper 10 generates a video pulse, for example, with a duration of 100 μs of a rectangular or bell-shaped (Gaussian) shape (Fig. 2 left and right).

When these signals are mixed, an acoustic radio pulse is formed in the modulator 11.

The generated acoustic radio pulse is amplified in the power amplifier 12 and then sent to the first input of the transmit-receive relay 6, the operation of which is controlled from the pulse shaper 10.

In real conditions, when the duration of acoustic radio pulses is 10 ^-4 s, the duty cycle of the sequence of radio pulses should be set equal to 10.

The optimal time parameters of the pulses and the modes of the experiments depend on the geometric dimensions of the well and the drill or tubing used in them, as well as on the nature of the alleged violations of the straightness of the wellbore.

AP1 with uniform CN during its uniform descent along the axis of the borehole (tubing 4) emits a sequence of acoustic radio pulses, which, reflected from the side walls of tubing 4, again arrive at the input of AP1, but shifted by time t.

The reflected signals received by AP1 using the receive-transmit relay 6 are sent through an amplifier-limiter 13 and a detector 14 to a computer 16, in which the width or broadening of the reflected acoustic radio pulse relative to the probe pulse and carrying information about the deflection of the tubing 4 at the measured depth L is calculated (information on the depth of the location of the AP1 in the well continuously enters the computer 16 from the depth sensor 5).

Figure 1 below shows cases a), b) and c) of the location of AP1 at various depths of the well.

In case a) AP1 is located at the same distance from the walls of tubing 4. In this case, the pulses reflected from the walls of the tubing 4 will arrive at the AP1 input simultaneously through the time t ₁ -t ₀ , where t ₀ is the radiation time, and t ₁ is the pulse receiving time, while the width of the total reflected pulse will not change and will be equal to Δt ₁ = Δt ₀ , where Δt ₀ is the width of the probe pulse. That is, the broadening of the probe pulse reflected from the walls is zero. This case is presented in figa.

The characteristics of the pulse attenuator 15 and the amplifier-limiter 13 are selected so that the transmitting (probing) and reflected (receiving) pulses are equal in shape and amplitude.

In section b) of tubing 4, the width of the received pulse increases due to the appearance of pipe curvature (Fig.3b), while with the increase in the pipe curvature (Fig.3c), the pulse broadening increases.

In this way it is impossible to determine in which direction the bent pipe is inclined. But in practice, it is much more important to determine the dimensions of the bend regardless of the cardinal points and to evaluate whether or not the bend of the pipe has reached a critical value, at which its replacement is required.

The deflection of the pipe is associated with the bending of the wellbore, which allows us to draw conclusions about the general technical condition of the well.

The calibration of an acoustic downhole tool in real, factory, or laboratory conditions allows us to relate the width Δt of the reflected pulse to the deflection of the pipe or well, which allows us to directly measure the bending (deflection) of the pipe in each section, for example, in units of length in a non-contact way.

This achieves the set technical result.

Claims (4)

1. A method of controlling the curvature of a borehole, which consists in measuring the deflection of a drill or tubing using a borehole tool that is lowered vertically into the borehole, characterized in that a reversible acoustic transducer with uniform directivity is used as the borehole device, working in mode of the sequence of probe pulses, while the magnitude of the deflection of the wellbore is judged by the broadening of the probe pulses reflected from the walls. 2. The method according to claim 1, characterized in that the sequence of radio pulses of a rectangular or bell-shaped shape is used as sounding acoustic pulses. 3. The method according to claim 2, characterized in that as the sounding acoustic radio pulses using a sequence of radio pulses, the following with a duty cycle equal to 10. 4. The method according to claim 1, characterized in that as sounding acoustic pulses using radio pulses with a duration of 10 ^{-4 C.}

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