A formation acoustic interval transit time combination measuring device and method

Abstract

The application provides a formation acoustic wave time difference combined measuring device and method, the device comprises a digital acoustic logging instrument and a dipole acoustic logging instrument, wherein, when the well to be measured is arranged, the digital acoustic logging instrument and the dipole acoustic logging instrument are arranged from the bottom to the top of the well to be measured in sequence, and the arrangement interval between the digital acoustic logging instrument and the dipole acoustic logging instrument is greater than or equal to a preset threshold value, the complementary combination of the respective measuring advantages of the dipole acoustic logging instrument and the digital acoustic logging instrument can effectively control the risk of failure of instrument data acquisition under complex well conditions such as high temperature and high pressure, high inclination wells and horizontal wells, and improve the reliability of the formation acoustic wave time difference and the success rate of one-time data acquisition.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of logging technology in oil exploration and development, and particularly relates to a formation acoustic traveltime combination measuring device and method. BACKGROUND

[0002] Acoustic logging is a kind of logging method for judging the geological characteristics of the well wall formation and the wellbore engineering condition by measuring the acoustic properties of the well wall medium. The original waveform time domain data collected by the acoustic logging instrument can extract three traveltime information of the well wall formation, including the compressional wave traveltime, the shear wave traveltime and the Stoneley wave traveltime, which can be used to evaluate the geological information such as formation lithology, anisotropy and porosity. The commonly used acoustic logging instruments at present are the dipole acoustic logging instrument and the digital acoustic logging instrument, the former can provide three traveltime information of the formation at the same time, and the latter only provides the compressional wave traveltime information of the formation, and it is generally believed that the compressional wave traveltime provided by the digital acoustic logging is more reliable. With the gradual development of oil exploration and development reservoirs from shallow to deep and even super deep, complex well conditions such as high angle deviated wells and horizontal wells become the main well type, and at the same time, due to the increase of well depth, the downhole temperature and pressure increase significantly, and the high temperature and high pressure or even super high temperature and high pressure measuring environment becomes the norm, which further brings uncertainty to the success rate of one-time data acquisition of single logging instrument. SUMMARY

[0003] In order to ensure high logging efficiency and high success rate of one-time data acquisition, the purpose of the present application is to provide a formation acoustic traveltime combination measuring device and method to increase the reliability of formation acoustic traveltime measurement and greatly improve the success rate of one-time acquisition of formation acoustic traveltime.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0005] The present application provides a formation acoustic traveltime combination measuring device, which comprises a digital acoustic logging instrument and a dipole acoustic logging instrument, wherein, when arranged in the well to be measured, the digital acoustic logging instrument and the dipole acoustic logging instrument are arranged from the bottom to the top of the well to be measured, and the arrangement distance between the digital acoustic logging instrument and the dipole acoustic logging instrument is greater than or equal to a preset threshold value.

[0006] Preferably, other logging instruments are arranged between the digital acoustic logging instrument and the dipole acoustic logging instrument.

[0007] Preferably, the other logging instruments include a dual laterolog instrument, a four-arm caliper logging instrument, an insulating short section, a spectral gamma ray spectrometry logging instrument and a flexible short section, wherein, when arranged in the well to be measured, the dual laterolog instrument, the four-arm caliper logging instrument, the insulating short section, the spectral gamma ray spectrometry logging instrument and the flexible short section are arranged from the bottom to the top of the well to be measured.

[0008] Preferably, the dipole acoustic logging instrument comprises a first far monopole transmitter, a dipole transmitter, a first near monopole transmitter, a first acoustic barrier, and eight array receivers, wherein the first far monopole transmitter, the dipole transmitter, the first near monopole transmitter, the first acoustic barrier, the first array receiver, the second array receiver, the third array receiver, the fourth array receiver, the fifth array receiver, the sixth array receiver, the seventh array receiver, and the eighth array receiver are arranged from bottom to top of the well to be measured.

[0009] Preferably, the digital acoustic logging instrument comprises a second far monopole transmitter, a second near monopole transmitter, a second acoustic barrier, and four array receivers, wherein the second far monopole transmitter, the second near monopole transmitter, the second acoustic barrier, the first array receiver, the second array receiver, the third array receiver, and the fourth array receiver are arranged from bottom to top of the well to be measured.

[0010] Preferably, the preset threshold value is 10 meters.

[0011] A formation acoustic travel time combination measurement method based on the device, comprising the following steps:

[0012] The optimal center working frequencies of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively set;

[0013] The first far monopole acoustic waveform time domain signal, the dipole acoustic waveform time domain signal, and the first near monopole acoustic waveform time domain signal are collected by the dipole acoustic logging instrument;

[0014] The second far monopole acoustic waveform time domain signal and the second near monopole acoustic waveform time domain signal are collected by the digital acoustic logging instrument;

[0015] The longitudinal wave travel time, the transverse wave travel time, and the Stoneley wave travel time of the formation in which the well to be measured is located are obtained according to the obtained acoustic waveform time domain signals.

[0016] Preferably, the optimal center working frequencies of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively set, and the specific method is as follows:

[0017] The target signal threshold values of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively established;

[0018] The least square method is combined with the target signal threshold values to respectively establish the center working frequency optimization design objective functions of the dipole acoustic logging instrument and the digital acoustic logging instrument;

[0019] The constraint conditions of the center working frequency optimization design objective functions are set;

[0020] The optimal center working frequency of the dipole acoustic logging instrument and the digital acoustic logging instrument is obtained by solving the optimization objective function and constraint condition in combination with the least square method.

[0021] Preferably, the center working frequency optimization design objective functions of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively:

[0022] arg min f(fre_Txi)=(signal(fre_Txi)-Signal Txi ) 2

[0023] arg min f(fre_Ti)=(signal(fre_Ti)-Signal Ti ) 2

[0024] Wherein, arg min represents the value of the variable when the following formula reaches the minimum value; fre_Txi represents the center working frequency of the dipole acoustic logging instrument; fre_Ti represents the center working frequency of the digital acoustic logging instrument; Signal Txi represents the amplitude of the sound wave signal required to be obtained by each receiver of the dipole acoustic logging instrument; Signal Ti represents the amplitude of the sound wave signal required to be obtained by each receiver of the digital acoustic logging instrument; signal(fre_Txi) represents the signal amplitude of the dipole acoustic logging instrument at different center working frequencies; signal(fre_Ti) represents the signal amplitude of the digital acoustic logging instrument at different center working frequencies.

[0025] Preferably, the constraint condition of the center working frequency optimization design objective function is set as:

[0026] fre_Tx min ≤fre_Txi≤fre_Tx max

[0027] fre_T min ≤fre_Ti≤fre_T max

[0028] Wherein, fre_Tx min represents the lower limit of the center working frequency of the dipole acoustic logging instrument; fre_Tx max represents the upper limit of the center working frequency of the dipole acoustic logging instrument; fre_Txi represents the center working frequency of the dipole acoustic logging instrument; fre_Ti represents the center working frequency of the digital acoustic logging instrument; fre_T min represents the lower limit of the center working frequency of the digital acoustic logging instrument; fre_T max represents the upper limit of the center working frequency of the digital acoustic logging instrument.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The present application provides a formation acoustic time difference combined measurement device, which utilizes the respective measurement advantages of the dipole acoustic logging instrument and the digital acoustic logging instrument to complement each other, can effectively control the risk of failure of instrument data acquisition under complex well conditions such as high temperature and high pressure, high deviation wells and horizontal wells, and improve the reliability of formation acoustic time difference and the success rate of one-time data acquisition.

[0031] Meanwhile, the present application does not change the mechanical structure of the original dipole acoustic logging instrument and the digital acoustic logging instrument, but through ensuring the minimum distance between the two acoustic instruments and optimizing the center working frequency of the acoustic emission transducer, the acoustic signals of different emission-receiving combinations do not interfere with each other, the optimized combined formation P-wave time difference, S-wave time difference and Stoneley wave time difference information can be obtained, the risk of low data acquisition rate under complex well conditions such as high temperature and high pressure, high deviation wells and horizontal wells can be effectively controlled, the reliability of formation acoustic time difference and the success rate of one-time data acquisition are improved, and the efficiency of logging operation is improved. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The present application provides a formation acoustic time difference combined measurement device;

[0033] Figure 2 The present application provides an optimal design process of the center working frequency of the acoustic transducer;

[0034] Figure 3 The present application provides a formation acoustic time difference combined measurement process. DETAILED DESCRIPTION

[0035] In the following description, specific details are set forth such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, persons skilled in the art should understand that the present application can be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary details.

[0036] It should be understood that when used in the specification and the appended claims of the present application, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0037] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0038] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0039] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0041] Example 1

[0042] like Figure 1 As shown in the figure, this embodiment provides a formation acoustic time difference combined measurement device, which consists of a digital acoustic logging tool, other logging instruments and a dipole acoustic logging tool from bottom to top.

[0043] The dipole acoustic logging tool consists of a first far monopole transmitter Tx1, a dipole transmitter Tx2, a first near monopole transmitter Tx3, a first sound insulation body, and eight array receivers Rx1-Rx8.

[0044] The first far-field monopole transmitter Tx1, the dipole transmitter Tx2, the first near-field monopole transmitter Tx3, the first sound insulation body, the first array receiver Rx1, the second array receiver Rx2, the third array receiver Rx3, the fourth array receiver Rx4, the fifth array receiver Rx5, the sixth array receiver Rx6, the seventh array receiver Rx7, and the eighth array receiver Rx8 are arranged sequentially from bottom to top.

[0045] The digital acoustic logging tool consists of a second far monopole transmitter T1, a second near monopole transmitter T2, a second sound insulation body, and four array receivers R1-R4.

[0046] The second far-field monopole transmitter T1, the second near-field monopole transmitter T2, the second sound insulation body, the first array receiver R1, the second array receiver R2, the third array receiver R3, and the fourth array receiver R4 are arranged sequentially from bottom to top.

[0047] Different transmitter-receiver combinations can be used to simultaneously obtain formation acoustic P-wave time difference, S-wave time difference, and Stoneley wave time difference information. In order to ensure sufficient acoustic signal attenuation distance between the two acoustic logging instruments, it is necessary to ensure that the length of other logging instruments is more than 10 meters. Typically, other logging instruments consist of a dual-lateral logging tool, a four-arm caliper logging tool, an insulated sub, an energy spectrum gamma spectral logging tool, and a flexible sub, from bottom to top.

[0048] Other logging instruments can also measure other formation parameters, while ensuring that the two sonic logging instruments are sufficiently spaced.

[0049] Example 2

[0050] like Figure 2 As shown, the flowchart illustrates the optimized design of the center operating frequency of the dipole acoustic logging tool and the digital acoustic logging tool. Therefore, this embodiment provides a method for optimizing the center operating frequency of a formation acoustic time difference combined measurement device. The dipole acoustic logging tool and the digital acoustic logging tool are connected and combined into an acoustic instrument string. To ensure that the acoustic signals transmitted by each transmitter-receiver combination do not interfere with each other, an additional [something is added] between them. Figure 1 In addition to increasing the spacing of other logging instrument combinations shown, it is necessary to optimize the center operating frequency of the transmitting transducer. The specific optimization method includes the following steps:

[0051] S1, establish target signal thresholds for both dipole acoustic logging tools and digital acoustic logging tools, where the dipole acoustic logging tool corresponds to three transmission signal thresholds (Signal). Txi (i = 1, 2, 3), the digital acoustic logging tool corresponds to two signal thresholds: Signal Ti (i = 1, 2),

[0052] S2. Using the least squares method, establish the objective function for optimizing the center operating frequency of the dipole acoustic logging tool and the digital acoustic logging tool:

[0053] arg min f(fre_Txi)=(signal(fre_Txi)-Signal Txi )2 (1)

[0054] arg min f(fre_Ti) = (signal(fre _ Ti) - Signal ri ) 2 (2)

[0055] S3, set the constraint condition of the optimization design objective function according to the excited acoustic wave mode of the different working frequencies, which are respectively:

[0056] fre_Tx min ≤fre_Txi≤fre_Tx max (3)

[0057] fre_T min ≤fre_Ti≤fre_T max (4)

[0058] Wherein, arg min represents the value of the variable when the following formula reaches the minimum value; fre_Txi represents the center working frequency of the dipole acoustic logging instrument; fre_Tx min represents the lower limit of the center working frequency of the dipole acoustic logging instrument; fre_Tx max represents the upper limit of the center working frequency of the dipole acoustic logging instrument; fre_Ti represents the center working frequency of the digital acoustic logging instrument; fre_T min represents the lower limit of the center working frequency of the digital acoustic logging instrument; fre_T max represents the upper limit of the center working frequency of the digital acoustic logging instrument; Signal Txi represents the required amplitude of the acoustic wave signal obtained by each receiver of the dipole acoustic logging instrument; Signal Ti represents the required amplitude of the acoustic wave signal obtained by each receiver of the digital acoustic logging instrument; signal(fre_Txi) represents the signal amplitude of the dipole acoustic logging instrument at different center working frequencies; signal(fre_Ti) represents the signal amplitude of the digital acoustic logging instrument at different center working frequencies.

[0059] By using the optimization objective function and the constraint condition, the optimized center working frequency fc_Txi of the dipole acoustic logging instrument and the optimized center working frequency fc_Ti of the digital acoustic logging instrument are obtained by combining the least square method, at which the time domain signal quality of the acoustic wave received by the dipole acoustic logging instrument and the digital acoustic logging instrument is good, and they do not interfere with each other.

[0060] Example 3

[0061] As Figure 3As shown, the embodiment provides a formation acoustic time difference combined measurement method, in particular:

[0062] S11, the dipole acoustic logging instrument, other logging instruments and digital acoustic logging instrument are connected, combined into a logging instrument string, which can measure the dipole acoustic time difference and digital acoustic time difference information at one time.

[0063] On the basis of ensuring more than 10 meters distance between the dipole acoustic wave and the digital acoustic wave, the optimal center working frequency of the dipole acoustic logging instrument and the digital acoustic logging instrument is set respectively, with the change of the instrument string in the downhole with the change of the well depth, at different formation depths, the dipole acoustic logging instrument collects the first far monopole, dipole and first near monopole acoustic waveform time domain signals, at the same time, the digital acoustic logging instrument collects the second far monopole and second near monopole acoustic waveform time domain signals, the acoustic waveform time domain signals collected can obtain the acoustic time difference information of the formation, wherein the dipole acoustic logging instrument can obtain the formation acoustic longitudinal wave time difference DTC1, the formation acoustic shear wave time difference DTS and the formation acoustic Stoneley wave time difference DTST, the digital acoustic logging instrument can obtain the formation acoustic longitudinal wave time difference DTC2, the formation longitudinal wave time difference is obtained by the optimized combination of DTC1 and DTC2,

[0064] The specific method of the optimized combination is:

[0065] The dipole acoustic logging instrument and the digital acoustic logging instrument measure and obtain DTC1 and DTC2 respectively, according to the rock acoustic parameter information (such as Young's modulus and Poisson's ratio) of the formation to be measured, a more reasonable formation longitudinal wave time difference value is selected, since the digital acoustic logging instrument has a closer transmitting and receiving distance, the longitudinal wave time difference is less affected by the adjacent formation and the wellbore, and under normal circumstances, the final obtained longitudinal wave time difference DTC=DTC2.

[0066] In summary, the complementary combination of the dipole acoustic logging instrument and the digital acoustic logging instrument can effectively control the risk of instrument data acquisition failure under complex well conditions such as high temperature and high pressure, high inclination well and horizontal well, greatly improve the reliability of the formation acoustic time difference and the success rate of one-time data acquisition, and promote the improvement of the efficiency of logging operation.

[0067] From bottom to top, the digital acoustic logging instrument, other logging instrument combination and dipole acoustic logging instrument are combined and connected in sequence. The instrument combination string contains the far monopole, near monopole transmission and four array receiving transducers of the digital acoustic instrument, the far monopole, dipole and near monopole transmission and eight array receiving transducers of the dipole instrument. The other logging instrument combination contains the lateral, caliper, insulation short section, energy spectrum and flexible short section from bottom to top, and the total length is ensured to be more than 10 m. On the basis of not changing the existing mechanical structure of the two acoustic instruments, on the one hand, the interval distance between the two acoustic instruments is ensured to be more than 10 m, and on the other hand, the target response threshold is set for each acoustic transmission transducer, the center working frequency of the acoustic transducer is optimized and designed, the mutual interference of each part of acoustic signal is ensured, and the effectiveness of the received transducer in collecting acoustic waveform time domain signal is ensured. According to the collected acoustic waveform, the dipole acoustic instrument can obtain the longitudinal wave time difference, transverse wave time difference and Stoneley wave time difference information of the formation, and the digital acoustic instrument can obtain the longitudinal wave time difference information of the formation. The time difference results are optimized and combined to output, and finally the three time difference information of the formation acoustic wave is obtained.

[0068] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A formation interval transit time combination measuring device characterized by, The device comprises a digital acoustic logging instrument and a dipole acoustic logging instrument, wherein, when arranged in a well to be measured, from the bottom to the top of the well to be measured, the digital acoustic logging instrument and the dipole acoustic logging instrument are arranged in sequence, and the arrangement spacing between the digital acoustic logging instrument and the dipole acoustic logging instrument is greater than or equal to a preset threshold value. The preset threshold value is 10 meters.

2. The device for combined formation acoustic traveltime measurement according to claim 1, characterized in that, Other logging instruments are arranged between the digital acoustic logging instrument and the dipole acoustic logging instrument.

3. The device of claim 2, wherein, The other logging instruments comprise a dual lateral logging instrument, a four-arm caliper logging instrument, an insulation short section, a spectral gamma-ray spectrometry logging instrument, and a flexible short section, wherein, when arranged in a well to be measured, from the bottom to the top of the well to be measured, the dual lateral logging instrument, the four-arm caliper logging instrument, the insulation short section, the spectral gamma-ray spectrometry logging instrument, and the flexible short section are arranged in sequence.

4. The device of claim 1, wherein, The dipole acoustic logging instrument comprises a first far monopole transmitter, a dipole transmitter, a first near monopole transmitter, a first sound insulation body, and eight array receivers, wherein, from the bottom to the top of the well to be measured, the first far monopole transmitter, the dipole transmitter, the first near monopole transmitter, the first sound insulation body, the first array receiver, the second array receiver, the third array receiver, the fourth array receiver, the fifth array receiver, the sixth array receiver, the seventh array receiver, and the eighth array receiver are arranged in sequence.

5. The device of claim 1, wherein, The digital acoustic logging instrument comprises a second far monopole transmitter, a second near monopole transmitter, a second sound insulation body, and four array receivers, wherein, from the bottom to the top of the well to be measured, the second far monopole transmitter, the second near monopole transmitter, the second sound insulation body, the first array receiver, the second array receiver, the third array receiver, and the fourth array receiver are arranged in sequence.

6. A method of formation acoustic interval transit time combination measurement, comprising: The device based on any one of claims 1-5 comprises the following steps: Optimal center working frequencies of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively set; First far monopole acoustic waveform time domain signals, dipole acoustic waveform time domain signals, and first near monopole acoustic waveform time domain signals are collected by using the dipole acoustic logging instrument; Second far monopole acoustic waveform time domain signals and second near monopole acoustic waveform time domain signals are collected by using the digital acoustic logging instrument; According to the obtained acoustic waveform time domain signals, P-wave time difference, S-wave time difference, and Stoneley wave time difference of the formation where the well to be measured is located are obtained; the optimal center working frequencies of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively set, and the specific method is as follows: Target signal threshold values of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively set; Optimization design objective functions of the center working frequencies of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively established by using the least square method in combination with the target signal threshold values; Constraint conditions of the optimization design objective functions of the center working frequencies are set; The optimization design objective functions of the center working frequencies of the dipole acoustic logging instrument and the digital acoustic logging instrument are respectively solved by using the optimization objective functions and the constraint conditions in combination with the least square method; and the optimization design objective functions of the center working frequencies of the dipole acoustic logging instrument and the digital acoustic logging instrument are as follows: wherein, represents the value of the variable at which the following equation reaches a minimum value; represents the center operating frequency of the dipole sonic logging tool; represents the center operating frequency of the digital sonic logging tool; represents the amplitude of the sonic signal required to be obtained by each receiver of the dipole sonic logging tool; represents the amplitude of the sonic signal required to be obtained by each receiver of the digital sonic logging tool; represents the amplitude of the sonic signal of the dipole sonic logging tool at different center operating frequencies; represents the amplitude of the sonic signal of the digital sonic logging tool at different center operating frequencies; the constraint condition for setting the center operating frequency optimization design objective function is: wherein, represents the lower limit of the center working frequency of the dipole acoustic logging instrument; represents the upper limit of the center working frequency of the dipole acoustic logging instrument; represents the center working frequency of the dipole acoustic logging instrument; represents the center working frequency of the digital acoustic logging instrument; represents the lower limit of the center working frequency of the digital acoustic logging instrument; represents the upper limit of the center working frequency of the digital acoustic logging instrument.

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