Twin-well micro-logging data acquisition system and method

Abstract

The invention discloses a twin-well micro-logging data acquisition system and method, and relates to the technical field of seismic wave acquisition devices, in particular to a twin-well micro-logging data acquisition system, which comprises an excitation well and a receiving well drilled on a stratum at a Q value survey point position, and the stratum at the Q value survey point position comprises a low-speed stratum, a speed-reduction stratum and a high-speed stratum; the twin-well micro-logging data acquisition system further comprises an excitation component and a receiving component. The excitation component comprises an exploder and a cartridge bag string, the cartridge bag string is composed of at least three independent and parallel cartridge bags, the cartridge bag string is lowered into the excitation well, and all the cartridge bags are located in the ranges of the low-speed stratum, the speed-reduction stratum and the high-speed stratum respectively; single excitation or three-time excitation is adopted, the excitation frequency is small, seismic data are collected in the whole well section, the consistency of excited seismic wavelets is ensured, the multistage geophones and the stratum pushing force are basically the same, the consistency of receiving coupling conditions is also ensured, and scientific and reasonable basic data are provided for Q value investigation.

Description

Technical Field

[0001] The invention relates to the technical field of seismic wave acquisition devices, in particular to a dual-well micro-logging data acquisition system and method. Background Art

[0002] When seismic waves propagate in the strata, their energy and frequency will be absorbed and attenuated. In order to eliminate the influence of this factor on seismic data, it is necessary to conduct a detailed analysis of the stratigraphic structure near the surface and perform compensation processing. The quality factor Q characterizes the ratio of the energy originally stored in a seismic wave to the energy consumed in one cycle. The use of inverse Q filtering can effectively eliminate the near-surface influence in the three domains of time, frequency and space. However, the accurate acquisition of the surface Q value has always been a research difficulty. There are many methods for calculating Q, and no one method is suitable for all situations. No matter which method is used, it strongly depends on the quality of the seismic data.

[0003] At present, the most effective method is to calculate the Q value using the data collected by dual-well micro-logging. The existing technology is to drill two wells at adjacent locations. One is the excitation well and the other is the receiving well. Seismic waves are excited at different depths in the excitation well, and at least one geophone is arranged at the wellhead of the receiving well to receive seismic signals simultaneously with a geophone arranged at the bottom of the receiving well.

[0004] The main advantages of the existing technology are: this data acquisition method can obtain shot detection pair data in low-speed layers and high-speed formations, avoiding the defects of single-well micro-logging and only shot detection pairs in low-speed formations, facilitating the direct calculation of the Q value of high-speed formations, and greatly improving the accuracy of Q value investigations of near-surface formations; the deployment of detectors on the ground can ensure coupling with the formation, and the receiving conditions are completely consistent.

[0005] Research shows that the excitation depth and lithology are the main factors affecting the seismic wavelet. Therefore, the main problems of the existing technology are: the excitation is performed point by point at a certain depth interval in the whole well section, and the number of excitations is dozens or hundreds, which leads to low construction efficiency; due to the inconsistency of the excitation depth, lithology, and excitation coupling, the seismic wavelet is very different, resulting in inaccurate Q value calculation results; the amount of each explosive package is consistent, generally 20 detonators, and a micro-well logging project consumes about 2,000 detonators, which has a high safety risk and high acquisition cost; the excitation array is broken and cannot be recovered, and a large number of gun lines are left in the well, which is not conducive to environmental protection.

[0006] In summary, in order to solve the problems existing in the prior art, the present invention is proposed to solve them. Summary of the invention

[0007] 1. Technical issues to be solved

[0008] In view of the deficiencies in the prior art, the present invention provides a dual-well micro-logging data acquisition system and method, which solves the problems raised in the above-mentioned background technology.

[0009] (II) Technical solution

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions: a dual-well micro-logging data acquisition system, including an excitation well and a receiving well drilled on the formation at the Q value survey point position, the formation at the Q value survey point position includes a low-speed formation, a reduced-speed formation, and a high-speed formation; the dual-well micro-logging data acquisition system also includes an excitation component and a receiving component; the excitation component includes an blaster and a drug package string, the drug package string is composed of at least three independent parallel drug packages, the drug package string is lowered into the excitation well, and each drug package is respectively located within the range of the low-speed formation, the reduced-speed formation, and the high-speed formation, and the blaster is electrically connected to at least three drug packages respectively; the receiving component includes a first recorder, a second recorder, and a detector string, the detector string includes ninety-six channels with different lengths The detector group includes ninety-six detector groups which are bundled together by cable ties. The detector group includes detectors and cables. The lower end of the cable is electrically connected to the detector. The first recorder is electrically connected to the cables in the first to forty-eighth detector groups, respectively, and the second recorder is electrically connected to the cables in the forty-ninth to ninety-sixth detector groups, respectively. The detector string is lowered into the receiving well, and the detectors in the detector string are longitudinally arranged and distributed in the range of low-velocity formations, reduced-velocity formations, and high-velocity formations. The blaster is electrically connected to the trigger interfaces of the first recorder and the second recorder, respectively. The blaster is powered on to excite at least one explosive package, and simultaneously triggers the first recorder and the second recorder to receive seismic signals from each detector, thereby completing the acquisition of seismic data.

[0011] Optionally, the detectors in the first to ninety-sixth detector groups are arranged vertically in sequence from top to bottom in the receiving well; among them, the track spacing between two adjacent detectors in the first to eleventh detector groups is one meter, the track spacing between two adjacent detectors in the eleventh to twenty-eighth detector groups is two meters, the track spacing between two adjacent detectors in the twenty-eighth to forty-eighth detector groups is four meters, the track spacing between two adjacent detectors in the forty-ninth to eighty-sixth detector groups is four meters, and the track spacing between two adjacent detectors in the eighty-sixth to ninety-sixth detector groups is two meters.

[0012] Optionally, the spacing range between two adjacent detectors in the 48th to 49th detector group is selectively adjusted according to the depth of the receiving well under different working conditions.

[0013] Optionally, a weight is fixedly connected to the lower end of the detector string; the detector includes a shell, a plug, a detector core and at least two tail cones, the detector core is fixedly installed inside the shell, the plug is fixedly installed at the upper end port of the shell, the tail cone is fixedly installed on the outer wall of the shell, and the end of the tail cone away from the shell abuts against the wall of the receiving well.

[0014] Optionally, the tail cone uses a steel wire rope segment with a certain toughness.

[0015] The dual-well micro-logging data acquisition method comprises the following steps:

[0016] (A) Drilling: Drill a stimulation well and a receiving well on the formation at the Q value survey point, with the distance between the stimulation well and the receiving well being five to ten meters;

[0017] (B) Prepare the following equipment: a first recorder, a second recorder, a blaster, a heavy hammer, at least three explosive packs, ninety-six geophones, and ninety-six cables of varying lengths;

[0018] (C) Arrangement of data acquisition system: align the upper ends of ninety-six cables, electrically connect the lower end of each cable to a detector, and form a detector group after electrically connecting a cable and a detector. Use cable ties to bundle the cables in the ninety-six detector groups to form a detector string, and fix a heavy hammer at the lower end of the detector string. Lower the detector string into a receiving well; wherein, the detectors in the first to ninety-six detector groups are arranged longitudinally in the receiving well from high to low; form each drug package into a drug package string, and lower the drug package string into the excitation well, and there is a height difference between each drug package in the excitation well;

[0019] (D) Connecting equipment: the first recorder is electrically connected to the upper ends of the cables in the first to forty-eighth detector groups, respectively, and the second recorder is electrically connected to the upper ends of the cables in the forty-ninth to ninety-sixth detector groups, respectively; the blaster is electrically connected to the trigger interfaces of the first recorder and the second recorder, respectively; the blaster is electrically connected to the electric detonators in at least three explosive packs, respectively;

[0020] (E) Source excitation and data acquisition: The blaster is powered on to excite a charge and simultaneously trigger the first recorder and the second recorder to receive seismic signals from each detector, completing a seismic data acquisition;

[0021] (F) Repeat step (E) multiple times to achieve the goal of exciting a drug package in the low-speed formation, the deceleration formation, and the high-speed formation of the excitation well; collect seismic data of the low-speed formation, the deceleration formation, and the high-speed formation sources through the first recorder and the second recorder.

[0022] (III) Beneficial effects

[0023] The present invention provides a dual-well micro-logging data acquisition system and method, which has the following beneficial effects:

[0024] (1) Single or triple excitation, with a small number of excitations, collects seismic data in the entire well section, ensuring the consistency of the excited seismic wavelets. The multi-stage geophones and the formation push force are basically the same, which also ensures the consistency of the receiving coupling conditions, providing scientific and reasonable basic data for Q value investigation.

[0025] (2) The cable bundles of the distributed detectors do not touch the well surface, and the ground part of the well is in a relaxed state, which effectively weakens the interference of cable waves.

[0026] (3) Segmented design allows for flexible arrangement and is suitable for collecting micro-logging data at different well depths.

[0027] (4) The construction method has changed from multiple blasting in one pass to multiple blasting in one pass, which greatly reduces the number of blasting times, reduces construction costs and safety risks, and improves construction efficiency.

[0028] (5) The distributed detector arrangement is repeatedly used to avoid a large amount of excitation lines being left in the well and polluting the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0030] Figure 1 It is a schematic diagram of the structure of the dual-well micro-logging data acquisition system of the present invention when it is implemented;

[0031] Figure 2 It is a schematic diagram of the three-dimensional structure of the detector in the dual-well micro-logging data acquisition system and method of the present invention;

[0032] Figure 3 It is a schematic diagram of the arrangement structure of a section of a detector string in the dual-well micro-logging data acquisition system and method of the present invention;

[0033] Figure 4 It is a schematic diagram of the two-stage arrangement structure of the detector string in the dual-well micro-logging data acquisition system and method of the present invention;

[0034] Figure 5 Seismic data records received by the surface channel for excitation at different depths.

[0035] In the figure: 1. Detector; 101. Shell; 102. Plug; 103. Tail cone; 2. First recorder; 3. Second recorder; 4. Exploder; 5. Receiving well; 6. Excitation well; 7. Explosive bag; 8. Heavy hammer. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indications or implications.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments.

[0038] See also Figures 1 to 5 The present invention provides a technical solution: a dual-well micro-logging data acquisition system, including an excitation well 6 and a receiving well 5 drilled on the formation at the Q value survey point position, the formation at the Q value survey point position includes a low-speed formation, a reduced-speed formation, and a high-speed formation. The system also includes an excitation component and a receiving component.

[0039] The exciting component is used to implement source excitation at different depths (low velocity formation, reduced velocity formation, high velocity formation) of the exciting well 6. The receiving component is used to collect seismic data produced by the low velocity formation, reduced velocity formation, and high velocity formation. The bottom of the exciting well 6 is in the high velocity formation, the middle is in the reduced velocity formation, and the shallow layer is in the low velocity formation.

[0040] The excitation component includes an blaster 4 and a charge string, which is composed of at least three independent parallel charges 7. The charge string is lowered into the excitation well 6, and each charge 7 is respectively located within the range of a low-speed formation, a reduced-speed formation, and a high-speed formation. The blaster 4 is electrically connected to at least three charges 7, respectively.

[0041] Among them, the blaster 4 adopts the existing detonator detonation control equipment (such as eShot-I type detonation controller). The blaster 4 is electrically connected to the electric detonator in the medicine bag 7, and the blaster 4 is powered on to detonate the medicine bag 7, thereby exciting seismic waves. Each medicine bag 7 can excite a seismic source in the low-speed formation, the deceleration formation, and the high-speed formation in the excitation well 6. At least three independent and parallel medicine bags 7, each medicine bag 7 is electrically connected to the blaster 4 separately, and the blaster 4 detonates each medicine bag 7 in turn in different time periods.

[0042] The receiving component includes a first recorder 2, a second recorder 3, and a detector string. The detector string includes ninety-six detector groups with different lengths. The ninety-six detector groups are bundled by cable ties. The detector group includes a detector 1 and a cable. The lower end of the cable is electrically connected to the detector 1. The first recorder 2 is electrically connected to the cables in the first to forty-eighth detector groups, respectively. The second recorder 3 is electrically connected to the cables in the forty-ninth to ninety-sixth detector groups, respectively. The detector string is lowered into the receiving well 5, and the detectors 1 in the detector string are arranged longitudinally and distributed in the range of low-speed formations, reduced-speed formations, and high-speed formations.

[0043] There are two sections of the detector string, the first to the 48th detector group is the first section of the detector string, and the 49th to the 96th detector group is the second section of the detector string. By making the detector string into two sections of distributed arrangement, the two-section multi-point position of the detector string collects seismic data.

[0044] The blaster 4 is electrically connected to the trigger interfaces of the first recorder 2 and the second recorder 3 respectively. The blaster 4 is powered on to excite at least one explosive pack 7, and simultaneously triggers the first recorder 2 and the second recorder 3 to receive seismic signals from each detector 1, thereby completing seismic data acquisition.

[0045] The first recorder 2 and the second recorder 3 include but are not limited to the GDZ48-channel engineering seismograph in the prior art. After the explosive pack 7 is triggered, multiple channels of micro-logging seismic data are received simultaneously. The positive and negative electrodes of the blaster 4 are connected to the first recorder 2 and the second recorder 3 in parallel. After the detonation key is pressed, the first recorder 2 and the second recorder 3 are triggered to record the seismic signals of the corresponding channels simultaneously.

[0046] Specifically, the detectors 1 in the first to ninety-sixth detector groups are arranged longitudinally from top to bottom in the receiving well 5. Among them, the distance between two adjacent detectors 1 in the first to eleventh detector groups is one meter, the distance between two adjacent detectors 1 in the eleventh to twenty-eighth detector groups is two meters, the distance between two adjacent detectors 1 in the twenty-eighth to forty-eighth detector groups is four meters, the distance between two adjacent detectors 1 in the forty-ninth to eighty-sixth detector groups is four meters, and the distance between two adjacent detectors 1 in the eighty-sixth to ninety-sixth detector groups is two meters. More specifically, the spacing range between two adjacent detectors 1 in the forty-eighth to forty-ninth detector groups is selectively adjusted according to the depth of the receiving well 5 under different working conditions.

[0047] Among them, the first to forty-eighth detector group is one section of the detector string, and the forty-ninth to ninety-sixth detector group is the second section of the detector string.

[0048] Take the receiving well 5 with a depth of 300m as an example: the first section (upper section) of the detector string is the 1st to 48th detector group, the first track corresponds to a depth of 0m, the track spacing from the 1st to the 11th track is 1m, the length is 10m, the 11th track corresponds to a depth of 10m, the track spacing from the 11th to the 28th track is 2m, the length is 34m, the 28th track corresponds to a depth of 44m, the track spacing from the 28th to the 48th track is 4m, the length is 80m, and the 48th track corresponds to a depth of 124m.

[0049] The second section (lower section) of the detector string is the 49th to 96th detector group. The 49th track corresponds to a depth of 128m. The track spacing from the 49th to the 86th track is 4m, the length is 152m, the 86th track corresponds to a depth of 280m, the track spacing from the 86th to the 96th track is 2m, the length is 24m, and the 96th track corresponds to a depth of 300m. Since the distance from the wellhead of receiving well 5 to the instrument connection is 10m, the total length is 310m.

[0050] The lengths of the cables in the detector string are different. The upper ends of the cables are aligned, and the lower ends of the cables correspond to the positions of the corresponding seismic channels. In the above example, the first channel corresponds to 10m, the second channel corresponds to 11m, the ninety-fifth channel corresponds to 308m, and the ninety-sixth channel corresponds to 310m.

[0051] The detector string has two independent cables, the upper and lower sections, each transmitting 48 signals. The upper and lower sections are serially combined to observe a 300m deep receiving well (micro-well logging). If the well is shallow, the upper and lower sections are partially combined in parallel, that is, the lower part of the upper section overlaps with the upper part of the lower section, and the track spacing changes from 4m to 2m. The position of the overlap is determined according to the depth of the receiving well, shortening the total length of the arrangement to adapt to different well depths; in this implementation process, the upper section of the detector string needs to be tied separately, and the lower end needs to be tied separately, that is, the upper and lower sections are tied separately.

[0052] Specifically, the lower end of the detector string is fixedly connected with a weight 8. The detector 1 includes a housing 101, a plug 102, a detector core and at least two tail cones 103. The detector core is fixedly installed inside the housing 101, the plug 102 is fixedly installed at the upper end port of the housing 101, and the tail cone 103 is fixedly installed on the outer wall of the housing 101. The end of the tail cone 103 away from the housing 101 abuts against the wall of the receiving well 5. The tail cone 103 uses a steel wire rope segment with a certain toughness.

[0053] During construction, the detector string is lowered into the receiving well 5, and the depth below the detector string is one meter deeper than the measured depth. Then it is lifted up one meter to make the detector string reach the depth to be measured. This process can make the steel wire rope segment on the detector 1 change from the stretched state in the receiving well 5 to the downward direction, that is, the end of the steel wire rope segment away from the housing 101 tilts downward to support the well wall. The housing 101 is made of metal and plastic. The diameter of the steel wire rope segment is 6mm and the length is about 250mm. The steel wire rope segment abuts against the well wall, which can effectively push the detector 1 to the center of the receiving well 5, avoid the detector 1 sticking to the well wall, and avoid the friction between the detector string and the formation rock when moving up and down and damaging the cable. The steel wire rope segment is always in good contact with the well wall formation, and the seismic waves propagating in the formation are transmitted to the detector 1 and picked up, thereby improving the coupling effect. The cable adopts a two-core cable, and the two cores of the cable are respectively electrically connected to the positive and negative poles of the detector core. The lower end of the cable passes through the plug 102. The detector core is sealed and waterproofed in the housing 101, specifically by using silicone rubber potting.

[0054] When the detector string is lowered into the receiving well 5, it is necessary to install an inelastic, high-strength non-metallic cable (the non-metallic cable can effectively weaken the interference of cable waves. If a metal cable is used, the seismic wave propagation speed is faster in metal than in the formation, and it becomes the first wave, which interferes with the direct wave propagating in the formation, affects the reading of the first arrival time, and interferes with the spectrum of the first arrival wave, causing errors in the Q value calculation). The detector string is tied to the cable in parallel. The cable is used to lower and lift the detector string in the well. The lower end of the cable is connected to a weight 8. The weight 8 weighs about 50 kg. The distance between the weight 8 and the lowest detector 1 is 3 m. The cable is raised and lowered by a lifting device in the prior art (such as a winch, etc.). When the detector string is lowered into the well, it is fixed to the cable at the wellhead with rope clips (such as drawbars, cable ties, etc.) at intervals of about 10 meters to drive the detector string into the receiving well 5. When recovering, the rope clips are quickly removed and the two are separately coiled on the drum.

[0055] The dual-well micro-logging data acquisition method comprises the following steps:

[0056] (A) Drilling: Drill an exciting well 6 and a receiving well 5 on the stratum at the Q value survey point. The distance between the exciting well 6 and the receiving well 5 is five to ten meters.

[0057] (B) Prepare the equipment: a first recorder 2, a second recorder 3, an explosive machine 4, a heavy hammer 8, at least three explosive packs 7, ninety-six detectors 1, and ninety-six cables of different lengths.

[0058] (C) Arrangement of data acquisition system: Align the upper ends of the ninety-six cables, and electrically connect the lower end of each cable to a detector 1. After electrically connecting one cable and one detector 1, a detector group is formed. The cables in the ninety-six detector groups are bundled with a cable tie to form a detector string. The weight 8 is fixedly installed at the lower end of the detector string, and the detector string is lowered into the receiving well 5. Among them, the detectors 1 in the first to ninety-six detector groups are arranged vertically from high to low in the receiving well 5. The individual drug packages 7 are made into a drug package string, and the drug package string is lowered into the excitation well 6. There is a height difference between the individual drug packages 7 in the excitation well 6.

[0059] (D) Connection equipment: The first recorder 2 is electrically connected to the upper ends of the cables in the first to forty-eighth detector groups, and the second recorder 3 is electrically connected to the upper ends of the cables in the forty-ninth to ninety-sixth detector groups. The blaster 4 is electrically connected to the trigger interfaces of the first recorder 2 and the second recorder 3. The blaster 4 is electrically connected to the electric detonators in at least three explosive packs 7.

[0060] (E) Source excitation and data acquisition: The blaster 4 is powered on to excite a charge 7 and simultaneously trigger the first recorder 2 and the second recorder 3 to receive seismic signals from each detector 1, thus completing a seismic data acquisition.

[0061] (F) Repeat step E for multiple times to achieve exciting a drug pack 7 in the low velocity formation, the reduced velocity formation, and the high velocity formation of the exciting well 6. The first recorder 2 and the second recorder 3 collect seismic data of the low velocity formation, the reduced velocity formation, and the high velocity formation.

[0062] This technical solution can adapt to common near-surface structures by implementing three-layer excitation in the low-speed formation, reduced-speed formation, and high-speed formation at the Q value survey point, and can directly calculate the Q value of each layer by using the peak frequency shift method to estimate the Q value; it has obvious advantages.

[0063] The basic principle of Q estimation is based on the changes in the spectral characteristics of seismic signals at different locations. At present, the near-surface Q value estimation uses the existing relatively mature algorithm theory in algorithm theory, and the classic spectral ratio method is the most widely used. Its theoretical basis is:

[0064] The amplitude spectrum of the seismic signal can be expressed as:

[0065]

[0066] Where: v is the formation velocity; S(f) is the frequency domain response of the source signal; G is an operator that is independent of frequency, including geometric diffusion, transmission loss, etc. The logarithm of the ratio of the amplitude spectrum at distances r2 and r1 is:

[0067]

[0068] Assuming that the two receiving points have the same source wavelet, the above formula is simplified to:

[0069]

[0070] Where: Δτ=(r2-r1) / v; ɑ is a constant independent of frequency; R(f)=ln[u(r2,f)] / [u(r1,f)] represents the attenuation function. It can be seen that R(f) is a linear function of frequency f, and its slope is p=-πQ-1Δt. The quality factor Q can be estimated by fitting the slope of the attenuation curve:

[0071]

[0072] From the estimation principle of Q-value spectrum ratio method, it can be seen that it must be based on the same source wavelet at two receiving points. Therefore, to accurately estimate the Q value, the consistency of the source seismic wavelet must be ensured.

[0073] Generally, the near-surface structure is divided into three layers: low, descending, and high-speed. The seismic wavelets excited by the same layer are basically the same, while the wavelets of different layers are quite different. Figure 5 , Figure 5The following are the records of ground channel reception after excitation at different depths. It can be seen that the seismic wavelet energy of channels 60 (yellow line) to 64 (corresponding to depths of 62, 58, 54, 50, and 46m) is much weaker than that of channels 59-56 (corresponding to depths of 68, 72, 76, and 80m). Theoretically, when the excitation energy is kept consistent, the excitation depth is deep, the propagation distance is long, the signal attenuation is large, and the energy is weak. However, the actual record is abnormal. The reason for the analysis is that the depth is the interface between the deceleration formation and the high-speed formation. The depth of 62m is in the deceleration formation, while the depth of 68m is in the high-speed formation. Although the excitation energy is the same, the seismic wavelet is very different. Therefore, the use of existing dual-well micro-logging technology will lead to incorrect Q value estimation results.

[0074] According to the formula for estimating Q value by the peak frequency shift method, using the technology in the application number CN201010589345.7 of "Method for measuring Q value of near-surface formation by using double-well micro-logging technology", only Q1 in high-speed formation and Q2 in low-speed formation can be solved, which is only suitable for the special situation that there are only two layers near the surface. The present invention excites in three layers and can adapt to the general near-surface structure. The peak frequency shift method is used to estimate Q value, and the Q value of each layer can be directly calculated; it has obvious advantages.

[0075] Due to the serious absorption and attenuation of seismic waves near the surface of loess plateaus and large deserts, Q value investigation is extremely important. However, the low-velocity strata of this type of near-surface layer are thin, and the deceleration strata are thick. For example, the low-velocity strata in the actual data are only 6.28m, the thickness of deceleration stratum 1 is 53.66m, and the thickness of deceleration stratum 2 is 36.5m. However, the technical requirements are that there should be no less than 4 observation points in each stratum. In order to ensure that the observation points in the thinner low-velocity strata meet the standards, the spacing of detector 1 is increased, the deceleration stratum is thick, and the spacing between detectors is increased to avoid waste of resources. Therefore, detectors (observation points) with different spacings should be set.

[0076] Advantages of multi-segment settings 1: The well depth can be designed according to micro-logging, and the combination of series and parallel can be selected to adjust the total length of the arrangement to cover all observation well sections, and the data collection work of the entire well section can be completed in one excitation.

[0077] Advantage 2: When the number of arrangement channels (number of transmission cable cores) is the same, they are made separately, the diameter of a single cable becomes thinner, and the interference of cable waves is reduced.

[0078] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A dual-well micro-logging data acquisition system, comprising an excitation well (6) and a receiving well (5) drilled on the formation at the Q value survey point, characterized in that: The strata at the Q value survey point include low-speed strata, reduced-speed strata, and high-speed strata; the system also includes an excitation component and a receiving component. The excitation component comprises an blaster (4) and a cartridge string, wherein the cartridge string is composed of at least three independent parallel cartridges (7), the cartridge string is lowered into an excitation well (6), and each cartridge (7) is respectively located within a low-velocity formation, a reduced-velocity formation, and a high-velocity formation, and the blaster (4) is respectively electrically connected to the at least three cartridges (7); The receiving component comprises a first recorder (2), a second recorder (3), and a detector string. The detector string comprises ninety-six detector groups of different lengths. The ninety-six detector groups are bundled together by a cable tie. The detector group comprises a detector (1) and a cable. The lower end of the cable is electrically connected to the detector (1). The first recorder (2) is electrically connected to the cables in the first to forty-eighth detector groups respectively. The second recorder (3) is electrically connected to the cables in the forty-ninth to ninety-sixth detector groups respectively. The detector string is lowered into a receiving well (5), and the detectors (1) in the detector string are arranged longitudinally and distributed within the range of a low-speed formation, a reduced-speed formation, and a high-speed formation. The blaster (4) is electrically connected to the trigger interfaces of the first recorder (2) and the second recorder (3) respectively. When the blaster (4) is powered on, it excites at least one explosive bag (7) and simultaneously triggers the first recorder (2) and the second recorder (3) to receive seismic signals from each detector (1), thereby completing the acquisition of seismic data.

2. The dual-well micro-logging data acquisition system according to claim 1, characterized in that: The detectors (1) in the first to ninety-sixth detector groups are arranged longitudinally in sequence from top to bottom in the receiving well (5); wherein the track spacing between two adjacent detectors (1) in the first to eleventh detector groups is one meter, the track spacing between two adjacent detectors (1) in the eleventh to twenty-eighth detector groups is two meters, the track spacing between two adjacent detectors (1) in the twenty-eighth to forty-eighth detector groups is four meters, the track spacing between two adjacent detectors (1) in the forty-ninth to eighty-sixth detector groups is four meters, and the track spacing between two adjacent detectors (1) in the eighty-sixth to ninety-sixth detector groups is two meters.

3. The dual-well micro-logging data acquisition system according to claim 2, characterized in that: The spacing range between two adjacent geophones (1) in the 48th to 49th geophone group is selectively adjusted according to the depth of the receiving well (5) under different working conditions.

4. The dual-well micro-logging data acquisition system according to claim 1, characterized in that: A weight (8) is fixedly connected to the lower end of the detector string; the detector (1) comprises a housing (101), a plug (102), a detector core and at least two tail cones (103); the detector core is fixedly mounted inside the housing (101); the plug (102) is fixedly mounted at the upper end port of the housing (101); the tail cone (103) is fixedly mounted on the outer side wall of the housing (101); and one end of the tail cone (103) away from the housing (101) abuts against the wall of the receiving well (5).

5. The dual-well micro-logging data acquisition system according to claim 4, characterized in that: The tail cone (103) adopts a steel wire rope segment with certain toughness.

6. A dual-well micro-logging data acquisition method, characterized in that: The dual-well micro-logging data acquisition system according to any one of claims 1 to 5 comprises the following steps: (A) Drilling: Drilling a stimulation well (6) and a receiving well (5) on the formation at the Q value survey point, with the spacing between the stimulation well (6) and the receiving well (5) being five to ten meters; (B) preparing equipment: a first recorder (2), a second recorder (3), a blaster (4), a heavy hammer (8), at least three explosive packs (7), ninety-six detectors (1), and ninety-six cables of different lengths; (C) Arrangement of the data acquisition system: align the upper ends of the ninety-six cables, electrically connect the lower end of each cable to a detector (1), and after electrically connecting a cable and a detector (1), form a detector group. The cables in the ninety-six detector groups are bundled with a cable tie to form a detector string. A weight (8) is fixedly installed at the lower end of the detector string, and the detector string is lowered into the receiving well (5); wherein the detectors (1) in the first to ninety-six detector groups are arranged longitudinally in sequence from high to low in the receiving well (5); each drug package (7) is made into a drug package string, and the drug package string is lowered into the excitation well (6), and there is a height difference between each drug package (7) in the excitation well (6); (D) connection equipment: the first recorder (2) is electrically connected to the upper ends of the cables in the first to forty-eighth detector groups, respectively, and the second recorder (3) is electrically connected to the upper ends of the cables in the forty-ninth to ninety-sixth detector groups, respectively; the blaster (4) is electrically connected to the trigger interfaces of the first recorder (2) and the second recorder (3), respectively; the blaster (4) is electrically connected to the electric detonators in at least three explosive packs (7), respectively; (E) Seismic source excitation and data acquisition: the blaster (4) is powered on to excite a charge bag (7), and simultaneously triggers the first recorder (2) and the second recorder (3) to receive seismic signals from each detector (1), thus completing a seismic data acquisition; (F) Repeat step (E) multiple times to achieve the goal of exciting a drug package (7) in the low-speed formation, the reduced-speed formation, and the high-speed formation of the excitation well (6); and collect seismic data of the low-speed formation, the reduced-speed formation, and the high-speed formation earthquake sources through the first recorder (2) and the second recorder (3).

Images