CN107290722A - The localization method and device of microquake sources - Google Patents

Abstract

The invention discloses a kind of microquake sources localization method and device, wherein method includes：The relative bearing between perforation source and microquake sources is obtained according to perforation (being in same fracturing section with microseismic event) polarizing angle and microseism polarizing angle；The positional information in perforation source and the positional information of wave detector are obtained, the rate pattern that perforation P ripples signal is propagated is determined according to the positional information in perforation source, the positional information of wave detector, initial time and default relational model；According to the positional information of wave detector, microseism P ripples and S ripples initial time, rate pattern, default relational model and relative bearing, the position of microquake sources is determined under the conditions of preset search.The localization method and device for the microquake sources that the present invention is provided, the relative bearing between perforation source and microquake sources is determined by perforation polarizing angle and microseism polarizing angle, and constraints is used as using relative bearing, it may search for determining the position of microquake sources, the deviations brought during inverting microseism source position can be reduced.

Description

Method and device for locating microseismic source

technical field

The invention relates to the field of oil and gas exploration, in particular to a microseismic source positioning method and device.

Background technique

Hydraulic fracturing is a widely used oil and gas well stimulation measure. Hydraulic fracturing is currently the main form of natural gas extraction. It mainly uses a large amount of liquid mixed with chemicals to inject shale formations for hydraulic fracturing to release natural gas.

During the process of hydraulic fracturing, some small-magnitude seismic events are released while underground fractures are generated. These seismic events are accurately and quickly located and then the morphological characteristics of the fractures are reversed to evaluate the pressure effect. Mining provides a basis for decision-making.

Fig. 1 is the schematic diagram of the principle of positioning seismic events in the prior art. As shown in Fig. 1, the origin O is the origin of the well site coordinate system, and the P1 point is the sending point of the microseismic event, that is, the microseismic source. Since the P1 point and the O point There is fracturing fluid between them, which will cause the seismic wave signal at point P1 to produce the bending of the propagation path shown in the propagation process from point P1 to point O. Therefore, when inverting the position of point P1, that is, when locating the source position, Due to the bending of the propagation path, the microseismic source is inverted to the point P1', so the positioning deviation of the β angle will occur, and the error generated at this time is relatively large.

Contents of the invention

The purpose of the present invention is to provide a microseismic source positioning method and device to solve the problem of relatively large positioning errors when determining the position of the microseismic source in the prior art.

One aspect of the present invention provides a microseismic source positioning method, including:

Obtain the perforation signal sent by the perforation source, and extract the first arrival time of the perforation P wave signal from the perforation signal when it arrives at the detector;

Obtain the microseismic signal sent by the microseismic source, and extract the first arrival time when the microseismic P wave signal arrives at the geophone and the first arrival time when the microseismic S wave signal arrives at the geophone from the microseismic signal;

determining the perforation polarization angle according to the perforation P wave signal;

determining the microseismic polarization angle according to the microseismic P wave signal;

Obtain the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle; obtain the position information of the perforation source and the position information of the geophone, and obtain the position information of the perforation source according to the position information of the perforation source , the position information of the geophone, the first arrival time of the perforation P wave and the preset relationship model to determine the velocity model of the P wave signal, wherein the preset relationship model is the relationship between the position information, the first arrival time and the P wave propagation velocity relational model;

According to the position information of the geophone, the first arrival time of the microseismic P wave and the microseismic S wave, the velocity model, the preset relationship model and the relative azimuth, the position of the microseismic source is determined under preset search conditions.

Another aspect of the present invention provides a microseismic source positioning device, including:

The obtaining module is used to obtain the perforation signal sent by the perforation source, and extract the first arrival time when the perforation P wave signal arrives at the detector from the perforation signal;

The acquisition module is also used to obtain the microseismic signal sent by the microseismic source, and extract the first arrival time of the microseismic P wave signal arriving at the geophone and the first arrival time of the microseismic S wave signal arriving at the geophone from the microseismic signal;

a polarization angle determining module, configured to determine the perforation polarization angle according to the perforation P-wave signal;

The polarization angle determination module is also used to determine the microseismic polarization angle according to the microseismic P-wave signal;

The polarization angle determination module is also used to obtain the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle;

The positioning module is used to determine the position of the microseismic source under preset search conditions according to the position information of the geophone, the first arrival time of the microseismic P wave and the microseismic S wave, the velocity model, the preset relationship model and the relative azimuth.

The microseismic source positioning method and device provided by the present invention determine the relative azimuth between the perforation source and the microseismic source through the perforation polarization angle and the microseismic polarization angle, and use the relative azimuth as a constraint condition to search and determine the microseismic source. The position of the seismic source can reduce the positioning deviation caused by inversion of the micro-seismic source position in the prior art.

Description of drawings

FIG. 1 is a schematic diagram of the principle of locating seismic events in the prior art;

FIG. 2 is a schematic flow diagram of a microseismic source positioning method provided by Embodiment 1 of the present invention;

Fig. 3 is a schematic diagram of determining the relative polarization angle provided by Embodiment 1 of the present invention;

Fig. 4 is the layered structure of the underground medium provided by Embodiment 1 of the present invention;

5 is a schematic flow diagram of a microseismic source positioning method provided in Embodiment 2 of the present invention;

FIG. 6 is a schematic diagram of a time window of a first preset length and a second preset time window provided by Embodiment 2 of the present invention;

Fig. 7 is a schematic structural diagram of a positioning device for a microseismic source provided in Embodiment 3 of the present invention.

FIG. 8 is a schematic flow chart of a microseismic source positioning method provided by Embodiment 3 of the present invention.

detailed description

Embodiment one

This embodiment provides a method for locating a microseismic source, and the method and process described here may be included in a hardware module or device. These modules or devices may include, but are not limited to: Application Specific Integrated Circuit (ASIC) chips, Field Programmable Gate Arrays (FPGAs), dedicated or shared processors that execute a particular software module or piece of code at a particular moment, and/or now known Or other programmable logic devices developed in the future. When the described hardware modules or devices are activated, they perform the methods and processes included therein.

Fig. 2 is a schematic flow chart of the positioning method of the microseismic source provided by Embodiment 1 of the present invention. As shown in Fig. 2, the positioning method of the microseismic source includes:

In step 101, the perforation signal sent by the perforation source is obtained, and the first arrival time of the perforation P-wave signal arriving at the detector is extracted from the perforation signal.

Step 102, acquiring the microseismic signal sent by the microseismic source, and extracting the first arrival time of the microseismic P wave signal arriving at the geophone from the microseismic signal.

Wherein, the perforation signal refers to the signal after the acoustic wave signal emitted by the perforating gun is converted into an electrical signal, and the perforating gun is generally arranged at the perforation source.

Specifically, the perforation signal and the microseismic signal emitted by the microseismic source can be detected and obtained by the geophone, and then the execution subject of this embodiment obtains the perforation signal and the microseismic signal detected by the geophone.

The order in which the perforation signal and the microseismic signal are obtained is not limited. The two events can be regarded as independent events in time, that is, the perforation signal can be obtained first, and the microseismic signal can be obtained first. The microseismic signal is obtained, and then the perforation signal is obtained. Of course, both can also be obtained simultaneously.

Step 103, determining the perforation polarization angle according to the perforation P-wave signal.

Step 104, determining the microseismic polarization angle according to the microseismic P-wave signal.

In a preferred embodiment, the perforation signal sent by the perforation source is obtained, and the first arrival time of the perforation P wave signal to the detector is extracted from the perforation signal. Extract the first arrival moment when the perforation S-wave signal arrives at the detector.

The same method is used to determine the perforation polarization angle and the microseismic polarization angle, and of course different methods can be used to determine the perforation polarization angle and the microseismic polarization angle respectively. Specifically, the method for determining the polarization angle disclosed in the prior art may be used for implementation, which will not be repeated here.

Step 105, obtaining the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle.

Specifically, the relative azimuth is determined according to the difference between the perforation polarization angle and the microseismic polarization angle. FIG. 3 is a schematic diagram of determining a relative polarization angle provided by Embodiment 1 of the present invention.

As shown in Fig. 3, B1 is the location of the perforation source, and B2 is the location of the microseismic source. Due to the presence of fracturing fluid, the propagation paths of the perforation signal and the microseismic signal are curved paths as shown by the dotted line. According to the polarization angle of the perforation, the inversion of the location of the perforation source is B1', and the inversion of the location of the microseismic source according to the polarization angle of the microseismic source is B2'. The propagation path is also similar, so the angle μ between the inversion source position B1' and the inversion microseismic source position B2' and the origin O of the coordinate system can be approximated as the angle μ between the perforation source and the microseismic source relative azimuth.

Wherein, the origin O of the coordinate system can be established on the geophone, that is, the geophone can be used as the coordinate origin. Of course, other locations can also be established.

Step 106: Obtain the location information of the perforation source and the location information of the geophone, and determine the perforation P according to the location information of the perforation source, the location information of the geophone, the first arrival time of the perforation P wave, and the preset relationship model. The layered velocity model of the wave signal in the underground medium, wherein the preset relationship model is the relationship model between position information, first arrival time and P-wave propagation velocity.

If the first arrival time of the perforation S-wave signal has been obtained, the same method can be used to determine a layered velocity model of the perforation S-wave signal in the underground medium. Otherwise, the S-wave velocity model is determined from the P-wave velocity model with a preset ratio of P-wave velocity to S-wave velocity. Wherein, the perforation signal refers to the signal after the acoustic wave signal emitted by the perforating gun is converted into an electrical signal, and the perforating gun is generally arranged at the perforation source.

Step 107, according to the location information of the geophone, the first arrival time of the microseismic P wave and the microseismic S wave, the velocity model, the preset relationship model and the relative azimuth, determine the position of the microseismic source under the preset search conditions.

Fig. 4 is the layered structure of the underground medium provided by Embodiment 1 of the present invention. As shown in Fig. 4, since the underground medium includes different medium layers, the propagation velocity of the P wave will change at different depths of the medium layer, Therefore, preferably, the velocity model is a layered velocity model, that is, the velocity of the P wave is a function of depth, and the velocity model is: v=V(Z), wherein, v is the propagation velocity of the P wave, and Z is P The depth of wave propagation, V is the functional relationship between the depth of P wave propagation and the propagation speed. In Fig. 4, the direction pointed by the coordinate axis is the depth direction of propagation.

Wherein, when the S wave determines the layered structure of the underground medium, the above-mentioned method can also be used, and the propagation velocity of the S wave can be brought into the v in the above formula, and the depth of the S wave propagation can be brought into the Z and S waves in the above formula The function between the depth of propagation and the propagation speed is brought into V in the above formula, and the layered model is determined according to the above method, which will not be repeated here.

In this embodiment, a rectangular coordinate system, where the origin of the coordinates does not coincide with the detector, is taken as an example for illustration. For example, if the position coordinates of the microseismic source are (X _m , Y _m , Z _m ), the position coordinates of the perforation source are (X _p , Y _p , Z _p ), and the position coordinates of the geophone are (X _r , Y _r , Z _r ), the first arrival time of the microseismic P wave signal sent from the microseismic source to the geophone is The first arrival time of the perforation P wave signal sent from the perforation source to the detector is The perforation P signal is v=V(Z) in the subsurface velocity model.

Since the position coordinates of the perforation source (X _p , Y _p , Z _p ) and the position coordinates of the geophone (X _r , Y _r , Z _r ) can be obtained, if the position coordinates of the perforation source (X _p , Y _p , Z _p ), the location coordinates of the geophone (X _r , Y _r , Z _r ), and the first arrival time of the perforation P wave signal Satisfy the preset relational model: Then, according to the preset model, the layered velocity model v=V(Z) of the P wave signal in the underground medium can be obtained through solution.

Since they are both P waves, the propagation speed of the perforation P wave signal in the underground medium is the same as that of the microseismic P wave signal in the depth direction of the underground medium, and then the layered velocity model of the microseismic P wave signal in the underground medium can be adopted by the The velocity model v=V(Z) obtained from the hole P wave signal acquisition.

The layered velocity model of the S-wave signal in the underlying medium can also adopt the same method as above, which will not be repeated here.

Furthermore, after determining the relative azimuth angle μ between the perforation source and the microseismic source, since the position of the perforation source and the location of the geophone are known, if the known microseismic P-wave and microseismic S-wave signals are in the underground The velocity model in the medium can determine the position of the microseismic source according to the preset relationship model.

The microseismic source positioning method provided in this embodiment determines the relative azimuth between the perforation source and the microseismic source through the perforation polarization angle and the microseismic polarization angle, and uses the relative azimuth as a constraint condition to search and determine the microseismic source The position of the microseismic source can reduce the positioning deviation caused by the inversion of the microseismic source position in the prior art.

Embodiment two

This embodiment is based on the first embodiment, and this embodiment further explains step 101 in the above embodiment. Fig. 6 is a schematic flow chart of the positioning method of the microseismic source provided by Embodiment 2 of the present invention. As shown in Fig. 6, the method includes:

Generally speaking, both the perforation P-wave signal and the microseismic P-wave signal include east-west component signals and north-south component signals.

The north-south component signal is the direction of the X axis in Figure 3, the vertical component signal is the direction of the Z axis in Figure 3, and the east-west component signal is the direction of the Y axis in Figure 3.

Optionally, the east-west component signal of the perforation P-wave signal can be selected to determine the first arrival time. Of course, when determining the first arrival time of the microseismic P-wave signal, the east-west component signal of the microseismic P-wave signal can also be selected to determine the first arrival time of the microseismic to the moment.

Step 1011, acquiring a first average energy value of the perforation P-wave signal within a time window of a first preset length.

Wherein, FIG. 5 is a schematic diagram of a time window of a first preset length and a second preset time window provided by Embodiment 2 of the present invention. As shown in FIG. 5 , the horizontal axis in FIG. 5 is a time axis.

Specifically, the first average energy value within the time window 1 of the first preset length of the perforating P-wave signal is acquired starting from the moment when the acoustic wave signal is emitted by the perforating gun. Wherein, the first average energy value is determined according to the amplitude of the perforation P-wave signal.

Step 1012, slide the time window 2 of the second preset length along the time axis within the time window 1 of the first preset length, and obtain the second average energy of the perforation P-wave signal within the time window of the second preset length value, wherein the length of the time window of the second preset length is smaller than the length of the time window of the first preset length.

Step 1013: Determine the first arrival moment of the perforation P-wave signal according to the ratio of the second average energy value to the first average energy value.

Specifically, when the time window 2 of the second preset length is slid within the time window 1 of the first preset length, multiple second average energy values may be acquired during the continuous sliding process. The energy ratio is obtained by dividing the second average energy value by the first average energy value, and the time corresponding to the time window of the second preset length corresponding to the largest energy ratio is selected among multiple energy ratios, and this moment is taken as the first arrival time .

Wherein, the moment corresponding to the time window 2 of the second preset length may be the previous moment corresponding to the time window 2 of the second preset length, that is, the moment on the left side of the time window 2 of the second preset length in FIG. 5 The time corresponding to one end, of course, may also be the time corresponding to the right end of the time window 2 of the second preset length. Of course, there may be other ways to determine the first arrival time according to the length of the time window 2 of the second preset length, which will not be repeated here.

In addition, the length of the time window of the first preset length can be set according to the moment of the acoustic wave signal emitted by the perforating gun and the distance between the perforating gun and the detector, which can preliminarily determine the first arrival of the perforating P wave signal to the detector The time range of the moment.

Step 102, acquiring the microseismic signal sent by the microseismic source, and extracting the first arrival time of the microseismic P wave signal arriving at the geophone and the first arrival time of the microseismic S wave signal arriving at the geophone from the microseismic signal.

Among them, the method of extracting the first arrival time of the microseismic P-wave signal from the microseismic P-wave signal is the same as the method of extracting the first arrival time of the perforation P-wave signal.

Specifically, obtain the third average energy value of the microseismic P-wave signal within the time window of the third preset length; slide the time window of the fourth preset length along the time axis within the time window of the third preset length, and obtain A fourth average energy value of the microseismic P-wave signal within a time window of a fourth preset length, wherein the time window of the fourth preset length is shorter than the time window of the third preset length.

The first arrival moment of the microseismic P-wave signal is determined according to the ratio of the fourth average energy value to the third average energy value.

Wherein, the length of the time window of the third preset length is different from the length of the time window of the first preset length

Step 103, determining the perforation polarization angle according to the perforation P-wave signal.

Wherein, determining the perforation polarization angle according to the perforation P wave signal specifically includes:

Step 1031, selecting the east-west component signal and north-south component signal of the perforation P-wave signal within a preset time length after the first arrival time of the perforation.

Step 1032, calculate the covariance matrix of the two component signals according to the east-west component signal and the north-south component signal.

Step 1033, the elements in the covariance matrix determine the perforation polarization angle.

Step 104, determining the microseismic polarization angle according to the microseismic P-wave signal.

specific,

u _i (t), u _j (t): two horizontal components of the perforation signal,

θ: is the perforation polarization angle,

c _ij : covariance matrix elements,

T: perforation period.

Among them, the method of determining the microseismic polarization angle according to the microseismic P wave signal is similar to the method of determining the perforation polarization angle, that is, the east-west component signal and the north-south component signal of the microseismic P-wave signal within a preset time period after the first arrival of the microseismic signal are selected. , further, calculate the covariance matrix of the two component signals according to the east-west component signal and the north-south component signal, and determine the microseismic polarization angle according to the elements in the covariance matrix.

Step 105, obtaining the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle.

Step 106: Obtain the position information of the perforation source and the position information of the geophone, and determine that the perforation P-wave signal is in the underground A layered velocity model of the medium, wherein the preset relationship model is a relationship model among position information, first arrival time, and P-wave propagation velocity.

Step 107, according to the location information of the geophone, the first arrival time of the microseismic P wave and the microseismic S wave, the velocity model, the preset relationship model and the relative azimuth, determine the position of the microseismic source under the preset search conditions.

Specifically, after determining the subsurface velocity model v=V(Z) of the perforation P-wave signal, the velocity model v=V(Z), the position coordinates of the geophone (X _r , Y _r , Z _r ) and the microseismic P first arrival time of the wave signal and the first arrival moment of the microseismic S wave signal Substituting into the preset relational model F, it can be based on Determine the position coordinates of the microseismic source and the first arrival time of the microseismic The relationship between the location coordinates of the microseismic source and the first arrival time of the microseismic relationship between.

Due to the moment of the first arrival of the microearthquake There may be multiple position coordinates of the corresponding microseismic source. Therefore, the relative azimuth angle can be used as a constraint. The location coordinates of the microseismic sources are searched.

According to the position information of the geophone, the position coordinates (X _m0 , Y _m0 , Z _m0 ) of the searched initial microseismic source are set within a preset spatial range, wherein the preset spatial range is determined according to the relative azimuth.

Substitute the position coordinates of the geophone (X _r , Y _r , Z _r ) and the position coordinates of the initial microseismic source (X _m0 , Y _m0 , Z _m0 ) (X _n0 , Y _n0 , Z _n0 ) into the preset relationship model F, to obtain the theoretical first arrival moment corresponding to the position of the initial microseismic source that is based on Sure

If the theoretical first arrival time of microseismic P wave and the moment of first arrival of microseismic P wave The square of the difference between , and the theoretical first arrival time of the microseismic S wave and the moment of first arrival of microseismic S wave The sum of the squares of the differences is less than or equal to the first preset threshold, namely Then determine the position of the initial microseismic source as the position of the target microseismic source, where l is the first preset threshold.

The sum of the squares of the above theoretical first arrival times is greater than the preset threshold, that is, Then re-determine the position of the initial microseismic source within the preset spatial range until the target microseismic source whose sum of the squares of the above theoretical first arrival times is less than or equal to the preset threshold is found.

Among them, what needs to be explained is that if there are multiple detectors, the theoretical first arrival time of each detector The microseismic first arrival time corresponding to the theoretical first arrival time of each geophone The sum of the squares of the differences is less than or equal to the second preset threshold as a constraint condition, that is Re-determine the position of the initial microseismic source within the preset spatial range until the sum of the squares of the difference between the theoretical first arrival time and the first arrival time of each geophone is found to be less than or equal to the target microseismic source corresponding to the second preset threshold, Wherein, i is the serial number of the detector, and λ is the second preset threshold.

The microseismic source positioning method provided in this embodiment determines the relative azimuth between the perforation source and the microseismic source through the perforation polarization angle and the microseismic polarization angle, and uses the relative azimuth as a constraint condition to search and determine the microseismic source The position of the microseismic source can reduce the positioning deviation caused by the inversion of the microseismic source position in the prior art.

Embodiment three

This embodiment provides a microseismic source positioning device, which is used to implement the microseismic source positioning method in the above-mentioned embodiment 1 and embodiment 2, wherein, Fig. 7 shows the structure of the microseismic source positioning device provided by the third embodiment of the present invention Schematic diagram, as shown in FIG. 7 , the microseismic source positioning device includes: an acquisition module 71 , a polarization angle determination module 72 , a velocity model determination module 73 and a positioning module 74 .

The acquisition module 71 is configured to acquire the perforation signal sent by the perforation source, and extract the first arrival time of the perforation P-wave signal to the detector from the perforation signal.

The acquisition module 71 is also used to acquire the microseismic signal sent by the microseismic source, and extract the first arrival time of the microseismic P wave signal to the geophone and the first arrival time of the microseismic S wave signal to the geophone from the microseismic signal.

The polarization angle determination module 72 is connected with the acquisition module 71, and is used to determine the perforation polarization angle according to the perforation P wave signal;

The polarization angle determination module 72 is also used to determine the microseismic polarization angle according to the microseismic P wave signal;

The polarization angle determination module 72 is also used to obtain the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle.

The velocity model determination module 73 is used to obtain the position information of the perforation source and the position information of the geophone, and determine the P wave according to the position information of the perforation source, the position information of the geophone, the first arrival time of the perforation and the preset relationship model The layered velocity model of the signal in the underground medium, wherein the preset relationship model is the relationship model between position information, first arrival time and P-wave propagation velocity.

Preferably, the velocity model determined by the velocity model determination module 73 is a layered velocity model.

The positioning module 74 is respectively connected with the polarization angle determination module 72 and the velocity model determination module 73, and is used to base on the position information of the geophone, the first arrival time of the microseismic P wave and the microseismic S wave, the velocity model, the preset relationship model and relative Azimuth, to determine the location of microseismic sources under preset search conditions.

Specifically, the execution process of the acquisition module 71, the polarization angle determination module 72, the velocity model determination module 73 and the positioning module 74 can refer to the method in the first embodiment above, and will not be repeated here.

In the positioning device of the microseismic source provided in this embodiment, the polarization angle determination module 72 determines the relative azimuth between the perforation source and the microseismic source through the perforation polarization angle and the microseismic polarization angle, and the positioning module 74 uses the relative azimuth as the Constraint conditions, the location of the microseismic source can be searched and determined, and the positioning deviation caused by the inversion of the microseismic source position in the prior art can be reduced.

Embodiment four

In this embodiment, on the basis of the third embodiment above, further supplements and explanations are made for the positioning device of the microseismic source.

As shown in FIG. 7 , the acquisition module 71 extracts the first arrival moment when the perforation P-wave signal arrives at the geophone, and specifically acquires the first average energy value of the perforation P-wave signal within a time window of a first preset length. , and slide the time window of the second preset length along the time axis within the time window of the first preset length, and obtain the second average energy value of the perforation P-wave signal within the time window of the second preset length, wherein , the length of the time window of the second preset length is less than the length of the time window of the first preset length, and finally the initial value of the perforation P-wave signal is determined according to the ratio of the second average energy value to the first average energy value to the moment.

Optionally, the perforation P-wave signal includes an east-west component signal and a north-south component signal; correspondingly, the polarization angle determination module 72 is specifically used to: select the perforation P-wave signal within a preset time length after the initial arrival time of the perforation East-west component signals and north-south component signals, the covariance matrix of the two component signals is calculated according to the east-west component signals and north-south component signals, and the perforation polarization angle is determined according to the elements in the covariance matrix.

specific,

u _i (t), u _j (t): two horizontal components of the perforation signal,

θ: is the perforation polarization angle,

c _ij : covariance matrix elements,

T: perforation period.

The positioning module 74 is specifically used to set the position coordinates of the initial microseismic source to be searched within a preset spatial range according to the position information of the geophone, and the preset spatial range is determined according to the relative azimuth;

Substituting the position information of the geophone and the position information of the initial microseismic source into the preset relationship model to obtain the theoretical first arrival time of P wave and S wave corresponding to the position of the microseismic source;

If the square of the difference between the theoretical first arrival time corresponding to the microseismic P wave and the first arrival time corresponding to the microseismic P wave, the square of the difference between the theoretical first arrival time corresponding to the S wave and the first arrival time of the microseismic wave corresponding to the S wave, and, that is, the sum of the squares is less than or equal to the preset threshold, then it is determined that the position of the initial microseismic source is the position of the target microseismic source;

If the sum of the squares at the theoretical first arrival time is greater than the preset threshold, then re-determine the position of the initial microseismic source within the preset space until the search results in the sum of the squares at the theoretical first arrival time being less than or equal to the preset threshold Corresponding target microseismic source.

The execution process of the acquisition module 71 , the polarization angle determination module 72 , the velocity model determination module 73 and the positioning module 74 in the microseismic source positioning device provided in this embodiment can refer to the second embodiment, and will not be repeated here.

In the positioning device of the microseismic source provided in this embodiment, the polarization angle determination module 72 determines the relative azimuth between the perforation source and the microseismic source through the perforation polarization angle and the microseismic polarization angle, and the positioning module 74 uses the relative azimuth as the Constraint conditions, the location of the microseismic source can be searched and determined, and the positioning deviation caused by the inversion of the microseismic source position in the prior art can be reduced.

Embodiment five

This embodiment also provides a method for positioning a microseismic source. On the basis of the first and second embodiments above, as shown in FIG. 8, the method includes:

Step 801, acquiring a first average energy value of a perforation P-wave signal within a time window of a first preset length.

Step 802, within the time window 1 of the first preset length, slide the time window 2 of the second preset length along the time axis, and obtain the second average energy of the perforation P-wave signal within the time window of the second preset length value, wherein the length of the time window of the second preset length is smaller than the length of the time window of the first preset length.

Step 803: Determine the first arrival moment of the perforation P-wave signal according to the ratio of the second average energy value to the first average energy value.

Step 804, obtain the position information of the perforation source and the position information of the geophone, and determine the position of the P wave signal in the underground medium according to the position information of the perforation source, the position information of the geophone, the first arrival time of the perforation and the preset relationship model. A layered velocity model, wherein the preset relationship model is the relationship model between position information, first arrival time and P-wave propagation velocity;

If the first arrival time of the S-wave signal has been obtained, the perforation S-wave can also use the same method to determine a layered velocity model of the S-wave signal in the underground medium. Otherwise, the S-wave velocity model is determined from the P-wave velocity model with a preset ratio of P-wave velocity to S-wave velocity.

Step 805, acquiring the microseismic signal sent by the microseismic source, and extracting the first arrival time of the microseismic P and S wave signals arriving at the geophone from the microseismic signal.

Step 806, acquiring the east-west component signal and north-south component signal of the perforation P-wave signal within a preset time length after the first arrival time of the perforation.

Step 807, calculate the covariance matrix of the two component signals according to the east-west component signal and the north-south component signal.

Step 808, the elements in the covariance matrix determine the perforation polarization angle.

Step 809, determining the microseismic polarization angle according to the microseismic P-wave signal.

Step 810, obtain the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle.

Step 811, according to the location information of the geophone, the first arrival time of microseismic P-wave and microseismic S-wave, velocity model, relationship model and relative azimuth, determine the position of the microseismic source under preset search conditions.

For the specific implementation manner of each step, reference may be made to Embodiment 1 and Embodiment 2, and details are not repeated here.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, passengers of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some 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 various embodiments of the present invention.

Claims (10)

1. A method for positioning a microseismic source, comprising: Obtain the perforation signal sent by the perforation source, and extract the first arrival time of the perforation P wave signal from the perforation signal when it arrives at the detector; Obtain the microseismic signal sent by the microseismic source, and extract the first arrival time when the microseismic P wave signal arrives at the geophone and the first arrival time when the microseismic S wave signal arrives at the geophone from the microseismic signal; determining the perforation polarization angle according to the perforation P wave signal; determining the microseismic polarization angle according to the microseismic P wave signal; Obtain the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle; obtain the position information of the perforation source and the position information of the geophone, and obtain the position information of the perforation source according to the position information of the perforation source , the position information of the geophone, the first arrival time of the perforation P wave and the preset relationship model to determine the velocity model of the P wave signal, wherein the preset relationship model is the relationship between the position information, the first arrival time and the P wave propagation velocity relational model; According to the location information of the geophone, the first arrival time of the microseismic P wave and the microseismic S wave, the velocity model, the preset relationship model and the relative azimuth, the location of the microseismic source is determined under the preset search conditions. 2. The method according to claim 1, characterized in that, utilizing the long and short time window method to extract the first arrival moment of the perforation P-wave signal arriving at the detector, specifically comprising: Acquiring a first average energy value of the perforation P-wave signal within a time window of a first preset length; sliding a time window of a second preset length along the time axis within the time window of the first preset length, and acquiring a second average energy value of the perforation P-wave signal within the time window of the second preset length , wherein the length of the time window of the second preset length is less than the length of the time window of the first preset length; The first arrival moment of the perforation P-wave signal is determined according to the ratio of the second average energy value to the first average energy value. 3. The method according to claim 1, wherein the perforation P-wave signal comprises east-west and north-south component signals; The determining the polarization angle of the perforation source according to the perforation P-wave signal includes: Select the east-west and south-north component signals of the perforation P-wave signal within the preset time length after the first arrival time of the perforation; According to described east-west direction, north-south direction component signal calculates the covariance matrix of two direction signals; determining the perforation polarization angle based on elements in the covariance matrix; <mrow><msub><mi>c</mi><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>=</mo><munderover><mo>&amp;Integral;</mo><mn>0</mn><mi>T</mi></munderover><msub><mi>u</mi><mi>i</mi></msub><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><msub><mi>u</mi><mi>j</mi></msub><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mi>d</mi><mi>t</mi></mrow> <mrow><mi>&amp;theta;</mi><mo>=</mo><msup><mi>cot</mi><mrow><mo>-</mo><mn>1</mn></mrow></msup><mrow><mo>(</mo><mfrac><mrow><msub><mi>c</mi><mn>22</mn></msub><mo>-</mo><msub><mi>c</mi><mn>11</mn></msub><mo>+</mo><msqrt><mrow><msup><mrow><mo>(</mo><msub><mi>c</mi><mn>11</mn></msub><mo>-</mo><msub><mi>c</mi><mn>22</mn></msub><mo>)</mo></mrow><mn>2</mn></msup><mo>+</mo><mn>4</mn><msubsup><mi>c</mi><mn>12</mn><mn>2</mn></msubsup></mrow></msqrt></mrow><mrow><mn>2</mn><msub><mi>c</mi><mn>12</mn></msub></mrow></mfrac><mo>)</mo></mrow></mrow> u _i (t), u _j (t): two horizontal components of the perforation signal, θ: is the perforation polarization angle, c _ij : covariance matrix elements, T: perforation period. 4. method according to claim 1, is characterized in that, described according to the position information of geophone, microseismic P wave and microseismic S wave first arrival moment, velocity model, preset relationship model and relative azimuth angle, in The location of the microseismic source is determined under preset search conditions including: According to the position information of the geophone, the position coordinates of the initial microseismic source searched are set within a preset spatial range, and the preset spatial range is determined according to the relative azimuth; Substituting the position information of the geophone and the position information of the initial microseismic source into the preset relationship model to obtain the theoretical first arrival time of P wave and S wave corresponding to the position of the microseismic source; If the square of the difference between the theoretical first arrival time corresponding to the microseismic P wave and the first arrival time corresponding to the microseismic P wave, the square of the difference between the theoretical first arrival time corresponding to the microseismic S wave and the first arrival time corresponding to the microseismic S wave, , that is, the sum of the squares is less than or equal to the preset threshold, then it is determined that the position of the initial microseismic source is the position of the target microseismic source; If the sum of the squares at the theoretical first arrival time is greater than the preset threshold, then re-determine the position of the initial microseismic source within the preset space until the search finds that the sum of the squares at the theoretical first arrival time is less than or equal to the preset threshold Corresponding target microseismic source. 5. The method according to claim 1, wherein the velocity model is a layered velocity model. 6. A positioning device for a microseismic source, comprising: The obtaining module is used to obtain the perforation signal sent by the perforation source, and extract the first arrival time of the perforation P wave signal from the perforation signal when it arrives at the detector; The acquisition module is also used to obtain the microseismic signal sent by the microseismic source, and extract the first arrival time of the microseismic P wave signal arriving at the geophone and the first arrival time of the microseismic S wave signal arriving at the geophone from the microseismic signal; a polarization angle determining module, configured to determine the perforation polarization angle according to the perforation P-wave signal; The polarization angle determination module is also used to determine the microseismic polarization angle according to the microseismic P-wave signal; The polarization angle determination module is also used to obtain the relative azimuth between the perforation source and the microseismic source according to the perforation polarization angle and the microseismic polarization angle; The positioning module is used to determine the position of the microseismic source under preset search conditions according to the position information of the geophone, the first arrival time of the microseismic P wave and the microseismic S wave, the velocity model, the preset relationship model and the relative azimuth. 7. The device according to claim 6, wherein the acquisition module is specifically configured to acquire a first average energy value of the perforation P-wave signal within a time window of a first preset length; sliding a time window of a second preset length along the time axis within the time window of the first preset length, and acquiring a second average energy value of the perforation P-wave signal within the time window of the second preset length , wherein the length of the time window of the second preset length is less than the length of the time window of the first preset length; The first arrival moment of the perforation P-wave signal is determined according to the ratio of the second average energy value to the first average energy value. 8. The device according to claim 6, wherein the perforation P-wave signal comprises an east-west component signal, a north-south component signal and a vertical component signal; correspondingly, the polarization angle determination module is specifically used for: Select the east-west and south-north component signals of the perforation P-wave signal within the preset time length after the first arrival time of the perforation; According to described east-west direction, north-south direction component signal calculates the covariance matrix of two direction signals; determining the perforation polarization angle based on elements in the covariance matrix; in, <mrow><mi>&amp;theta;</mi><mo>=</mo><msup><mi>cot</mi><mrow><mo>-</mo><mn>1</mn></mrow></msup><mrow><mo>(</mo><mfrac><mrow><msub><mi>c</mi><mn>22</mn></msub><mo>-</mo><msub><mi>c</mi><mn>11</mn></msub><mo>+</mo><msqrt><mrow><msup><mrow><mo>(</mo><msub><mi>c</mi><mn>11</mn></msub><mo>-</mo><msub><mi>c</mi><mn>22</mn></msub><mo>)</mo></mrow><mn>2</mn></msup><mo>+</mo><mn>4</mn><msubsup><mi>c</mi><mn>12</mn><mn>2</mn></msubsup></mrow></msqrt></mrow><mrow><mn>2</mn><msub><mi>c</mi><mn>12</mn></msub></mrow></mfrac><mo>)</mo></mrow><mo>;</mo></mrow> u _i (t), u _j (t): two horizontal components of the perforation signal, θ: is the perforation polarization angle, c _ij : covariance matrix elements, T: perforation period. 9. The device according to claim 6, wherein the positioning module is specifically used to set the position information of the initial microseismic source to be searched within a preset space range according to the position information of the geophone, and the The preset spatial range is determined according to the relative azimuth; Substituting the position information of the geophone and the position information of the initial microseismic source into the preset relationship model to obtain the theoretical first arrival time of P wave and S wave corresponding to the position of the microseismic source; If the square of the difference between the theoretical first arrival time corresponding to the microseismic P wave and the first arrival time corresponding to the microseismic P wave, the square of the difference between the theoretical first arrival time corresponding to the microseismic S wave and the first arrival time corresponding to the microseismic S wave, , that is, the sum of the squares is less than or equal to the preset threshold, then it is determined that the position of the initial microseismic source is the position of the target microseismic source; If the sum of the squares at the theoretical first arrival time is greater than the preset threshold, then re-determine the position of the initial microseismic source within the preset space until the search results in the sum of the squares at the theoretical first arrival time being less than or equal to the preset threshold Corresponding target microseismic source. 10 . The device according to claim 6 , wherein the velocity model determined by the velocity model determination module is a layered velocity model. 11 .