CN103576188B - A kind of seismic source location method of release rate error impact - Google Patents

Abstract

The invention provides the seismic source location method of a kind of release rate error impact, belong to field of seismic exploration.The inventive method position by known focus, ask for the velocity error model of and velocity correlation, velocity error model being applied in object function, then scans all possible hypocentral location, finding the coordinate of the minimum point of the value making object function is exactly the coordinate of focus to be positioned.The inventive method eliminates the earthquake location accuracy strong dependency to rate pattern, it is possible to realize being accurately positioned of focus, detects the change of underground structure and fluid by being accurately positioned focus, and then instructs exploitation and the exploitation of oil, natural gas etc..

Description

A kind of seismic source location method of release rate error impact

Technical field

The invention belongs to field of seismic exploration, be specifically related to the seismic source location side of a kind of release rate error impact Method, is mainly used in resources-type exploitation field, including the field of seismic exploration such as coal, oil and natural gas, also Can be used for the monitoring of engineering geophysics and the earthquake location of routine.

Background technology

Earthquakes location is one of problem most basic in seismology, for study such as seismic activity structure, Ball internal structure, focus this type of seismology such as geometric construction in basic problem significant.Earthquake is fixed Position problem is summarized simply as follows: according to the station to earthquake observational data then, determine the space coordinates of focus And the origin time of earthquake, sometimes give result appraisal.Based on scientific algorithm and the intelligent number of computer technology Value automatic positioning method becomes the main stream approach of current seismic location, now widely used computer location side Method is the classical way of Geiger and the various linear methods set up on this basis: co-located method, phase To positioning mode, and dual residual error method etc..

Earthquakes location technology is not only applicable to earthquake field, has been introduced in oil and coal at the end of the nineties In the resource exploitation industries such as charcoal, in exploitation, the event such as rock rupture is compared with earthquake, because its energy is less, Referred to as microseism, the monitoring technology of microseism can be good at understanding the change of underground, the most by extensively Apply at aspects such as Reservoir performance monitoring, geothermal activities monitoring, coalfield dynamic monitoring, engineering dynamic monitorings, Oil field Production development is monitored in real time significant to oil field development by microseism method.

The location to focus such as micro-seismic monitoring in earthquake location, oil-gas exploration and engineering dynamic monitoring Technology, its ultimate principle is identical, i.e. according to the time of advent and the geological model being finally inversed by, by minimum Least square method, makes quadratic sum hourage of hourage that the hypocentral location of location calculated and actual observation Minimum.Determined by hypocentral location precision by two aspect controlling factors, (1) rate pattern, rate pattern The most accurate, seismic source location precision is the highest, and vice versa, the whilst on tour error that (2) reality is observed.First Individual factor is determined, due to the limitation of observation system, rate pattern inverting mainly by the completeness of observation data Often the most extremely difficult, mainly show as multi-solution and application condition be big, second factor is main and instrument and Relevant operator are correlated with, for objective unmodifiable factor.

Summary of the invention

It is an object of the invention to solve a difficult problem present in above-mentioned prior art, it is provided that a kind of release rate is by mistake The seismic source location method of difference impact, is a kind of method of earthquake locating to rate pattern error relative insensitivity, Eliminate the earthquake location accuracy strong dependency to rate pattern, detect ground by focus is accurately positioned Lower structure and the change of fluid, instruct exploitation and the exploitation of oil, natural gas etc..

The present invention is achieved by the following technical solutions:

A kind of seismic source location method of release rate error impact, the described method position by known focus, Ask for the velocity error model of and velocity correlation, velocity error model is applied in object function, so The all possible hypocentral location of rear scanning, the coordinate finding the point of the value minimum making object function is exactly to be positioned The coordinate of focus.

Described ask for one and be achieved in that with the velocity error model of velocity correlation

It is provided with n geophone station, takes known focus A (x_a, y_a, z_a), calculate focus A by formula (3) and arrive The calculating whilst on tour of each geophone station is T_i ^A,

${T_i}^A=\frac{{l_i}^A}{v}---\left(3\right)$

Wherein, T_i ^AFor the calculating whilst on tour of focus A to i-th geophone station, For focus A to i-th detection The distance of point, v is spread speed, then the velocity error model at i geophone station is:

${\mathrm{\ϵ}}_i=\frac{{T_i}^A}{{t_i}^A}---\left(6\right)$

Wherein The observation whilst on tour of each geophone station, ε is traveled to for focus A_iFor the speed at i geophone station Error rate.

Described velocity error model is applied in object function, then scans all possible hypocentral location, Finding the coordinate of the minimum point of the value making object function is exactly that the coordinate of focus to be positioned is achieved in that

Any one focus to be positioned is handled as follows:

(1) from the observation whilst on tour of this focus to each geophone station, minimum observation whilst on tour, this minimum are found Observation geophone station corresponding to whilst on tour is set to geophone station K, then calculates the sight to each geophone station of this focus Surveying whilst on tour and this focus time difference observed between whilst on tour to geophone station K, this time difference is observation trip The row time difference；

(2) in given scope, according to described velocity error model and formula (5), each shake is calculated Source is to the calculating hourage of each geophone station, and asks for each focus calculating whilst on tour to each geophone station And each focus is to the time difference calculated between whilst on tour of geophone station K, and this time difference is for calculating travel-time difference；

$T_i=\frac{l_i}{{\mathrm{v\ϵ}}_i}---\left(5\right)$

(3) the calculating travel-time difference that the observation travel-time difference obtained with step (1) and step (2) obtain it Between the quadratic sum of difference be object function, the institute in traversal given range a little, makes the value of described object function The coordinate of minimum point is the coordinate of focus to be positioned.

Compared with prior art, the invention has the beneficial effects as follows: the inventive method eliminates earthquake location accuracy Strong dependency to rate pattern, it is possible to realize being accurately positioned of focus, by focus is accurately positioned from And detect the change of underground structure and fluid, instruct exploitation and the exploitation of oil, natural gas etc..

Accompanying drawing explanation

Fig. 1 is the model in the embodiment of the present invention 2.

Fig. 2 is the hourage observed in the embodiment of the present invention 2.

Fig. 3 is the section of the focus A that in the embodiment of the present invention 2, certain real data observes.

Fig. 4 is the section of the focus B that in the embodiment of the present invention 2, certain real data observes.

Fig. 5-1 is that Fig. 3 carries out in the embodiment of the present invention 2 hourage of pickup after residual correction.

Fig. 5-2 is that Fig. 4 carries out in the embodiment of the present invention 2 hourage of pickup after residual correction.

Fig. 6 is the step block diagram of the inventive method.

Detailed description of the invention

Below in conjunction with the accompanying drawings the present invention is described in further detail:

The first step: seismic source location method (prior art)

If the observation of n geophone station is t when arriving₁, t₂..., t_n, seek focus (x₀, y₀, z₀) and origin time of earthquake t₀, make Obtain object function

$\mathrm{\φ}(t_0,x_0,y_0,z_0)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{r}_i^2---\left(1\right)$

Minimum, wherein r_iFor then residual error；

r_i=t_i-t₀-T_i(x₀, y₀, z₀) (2)

T_iCalculating whilst on tour for focus to i-th geophone station.

$T_i=\frac{l_i}{v}---\left(3\right)$

Wherein l_iFor the distance of focus to the i-th geophone station, v is spread speed, make object function minimalization namely

${\▿}_{\mathrm{\θ}}\mathrm{\φ}\left(\mathrm{\θ}\right)=0---\left(4\right)$

(4) formula is to the variable θ derivation in function phi so that it is derivative is zero.

Wherein

$\mathrm{\θ}={(t_0,x_0,y_0,z_0)}^T,{\▿}_{\mathrm{\θ}}={(\frac{\∂}{{\∂t}_0},\frac{\∂}{{\∂tx}_0},\frac{\∂}{{\∂y}_0},\frac{\∂}{{\∂z}_0})}^T$

Given range Ω (its scope be according to location in practical situation determined by, such as seismic prospecting In, in well, inject fracturing liquid, by the way of pressure break, make stratum crushing, thus produce small focus, Stratum crushing scope is generally within 300 meters, and at most not over 500 meters, therefore given scope is Scope with 300 meters of pressure break center) in, traveling through all of θ value, φ minimum is asks for focal point (x₀, y₀, z₀)。

Second step: velocity error is set up and correction (innovation of the present invention)

In actual applications, the speed v in formula (3) is difficult to ask accurate, thus causes T_iError, finally leads Cause seismic source location is forbidden, and in order to overcome the problems referred to above, introduces velocity error parameter, formula (3) is rewritten as:

$T_i=\frac{l_i}{v{\mathrm{\ϵ}}_i}---\left(5\right)$

Wherein ε_iFor the velocity error ratio at i geophone station, { ε_i(i=1, n) } it is the error collection of all geophone stations Closing, this error set is referred to as error model.Asking for of error model, takes certain focal point oriented A(x_a, y_a, z_a), it is T by the calculating whilst on tour of formula (3) calculating focus A to each geophone station_i ^A, that Velocity error function at i geophone station is:

${\mathrm{\ϵ}}_i=\frac{{T_i}^A}{{t_i}^A}---\left(6\right)$

Wherein (namely t_i-t₀) it is the focus A observation whilst on tour that travels to each geophone station.Application Formula (5), (6) establish error model, and by error model, release rate model is forbidden the shadow caused Ringing, be greatly improved seismic source location precision, the selection principle of usual focus A is: precision in all seismic source location The point best with reliability (artificial experience judges, usually amplitude is strong, interference less, identification degree high), or Person is obtained position and the time of its observation of focus A by the mode of artificial excitation.Calculating whilst on tour is to calculate institute The hourage obtained, representing with capitalization T, observation whilst on tour is that actual observation obtains, and uses lower case t Represent.

As shown in Figure 6, the specifically comprising the following steps that of the inventive method

Known geophone station number is n, and focus is expressed as A, B and (the most judges A by artificial experience It is precision and the best point of reliability in all seismic source location), if focus A arrives the observation travelling of geophone station Shi Wei Focus B arrives the observation whilst on tour of geophone station Model velocity is v, Focus A, B are positioned such that:

(1) (the observation whilst on tour of each focus is to arrive the observation whilst on tour of each geophone station at focus A Known conditions, be to be obtained by identification technology in engineering) in find minimum observation trip During row If this geophone station is K, and take the difference of each observation whilst on tour and minima:

(A in formula represents focus A)

(2) in the range of given Ω, each focus is asked for each geophone station according to formula (3) Calculate whilst on tour T_i ^A, and take calculate whilst on tour with to geophone station K calculate whilst on tour time Between poor: ${\mathrm{\ΔT}}_i={T_i}^A-T_K^A$

(3) full search method is utilized to find out formula Minima, it is corresponding The coordinate of point is the coordinate of focus A；, determine focus A by step (1) to (3) Coordinate；

(4) error model { ε is calculated according to formula (6)_i(i=1, n) } (determine error by this step, use Calculating in step (6))；

(5) focus B is repeated step (1)；

(6) in the range of given Ω, each focus is asked for each geophone station according to formula (5) Calculate T hourage_i ^B, and take each geophone station calculate hourage and geophone station K time Between poor: ${\mathrm{\ΔT}}_i={T_i}^B-T_K^B$

(7) repeat step (3), obtain the coordinate of B.Full search method first supposing, certain point is exactly B Point, then l_iValue can try to achieve, a lot of such postulated point can be sought out in Ω scope, But make the only one of which that the value of formula (1) is minimum, then this point is exactly real B Point.

Successively all focus are completed location.

The effect of the present invention is verified by following two embodiment (theoretical model, a real data) Really:

Embodiment 1:

Embodiment 1 uses theoretical model to test.Fig. 1 is the model diagram in embodiment 1, totally five layers, The speed of every layer is V1, V2, V3, V4, V5, places two focus A, B, and wherein asterisk is focus A, Circle is focus B, and A point is located at (1100,1200) position, and B point is located at (950,1350) place, ground Observation position is (10～1000) rice, and in figure shown in arrow, A is known point, and B is the point needing location.

Fig. 2 is the hourage (i.e. when the observation of A and B arrives, step 1,2,3 all use) observed, The curve that in Fig. 2, series 1 is A point, the curve that series 2 is B point, (in Fig. 2, thick line (above) is Serial 2) unit of time is the second.Table 1 is under given different model, utilize the present invention location to focus B point, Only velocity variations in model, the degree of depth of every layer of model is constant.As it can be seen from table 1 it is correct at rate pattern Time (rate pattern 1 in table 1), focus B position error is 0, at rate pattern error monolayer 25% Time (rate pattern 2 in table 1), the focus B depth error 0 of location, lateral error is 5 meters, in speed When degree model error is the biggest (rate pattern 3 in table 1 and model 4), the depth localization error of focus is maximum Being 5 meters, lateral error is 20 meters to the maximum.By exploration means, actual rate pattern error is usually Controlling 10%, therefore, the precision of the seismic source location of the present invention is the highest.

Table 1

When being embodied as, it is possible to use c programming language, realize this with (SuSE) Linux OS system for platform Method described in invention, and trial effect is good；Simply a kind of side to seismic source location that the present invention provides Method, unrelated with programming language and operating system.

Embodiment 2:

Fig. 3 is the section of the focus A that certain real data observes, two survey line (detections of different azimuth The arrangement mode of point, the cymoscope of two lines receives altogether, and a survey line refers to arrange along a certain straight line to be permitted Many cymoscopes) signal that obtains, wherein A point position is known as (3353126.0,338361.0,2145.1).

Fig. 4 is the section of the focus B that certain real data observes, focus B location is unknown.

Fig. 5-1 be Fig. 3 is carried out residual correction (residual correction is a kind of correction means in seismic prospecting, It is mathematically to eliminate time difference change small in seismic channel, makes the time graph more smooth) trip picked up afterwards The row time, Fig. 5-2 be Fig. 4 is carried out residual correction after pickup hourage (Fig. 3 and Fig. 4 is carried out After residual correction pickup hourage be in Fig. 5-1 and Fig. 5-2 time graph, i.e. real data In A (Fig. 3) and the hourage of B (Fig. 4)), unit of time is millisecond.

Specifically, it is thus achieved that the arrival whilst on tour of focus A and focus B, by the inventive method step 1～6 Can obtain the location to focus B, its medium velocity is 4800m/s, log data provide.

The result utilizing the inventive method to position focus B is as shown in table 2:

	X	Y	Z
				Focus A	3353126.0	338361.0	2145.1
Focus B	3353126.0	386341.0	2125.0

Table 2

Embodiment 1 is theoretical model, and rate pattern is known, and focal point A and B is known, A and The observation whilst on tour of B is also known, and in real data i.e. embodiment 2, the observation whilst on tour of A and B is Known, focus A is known, but rate pattern and focus B are unknown, and the location positioning of B is purpose, Meanwhile, in theoretical model, assume that B location and rate pattern are unknown, are used for testing and checking the present invention Effect and the precision of location, because the accuracy of real data cannot be checked.

Technique scheme is one embodiment of the present invention, for those skilled in the art, On the basis of the invention discloses application process and principle, it is easy to make various types of improvement or deformation, Being not limited solely to the method described by the above-mentioned detailed description of the invention of the present invention, the most previously described mode is simply Preferably, and not restrictive meaning.

Claims (1)

1. the seismic source location method of a release rate error impact, it is characterised in that: described method is by known shake The position in source, asks for the velocity error model of and velocity correlation, velocity error model is applied to target In function, then scan all possible hypocentral location, find the coordinate of the point of the value minimum making object function It it is exactly the coordinate of focus to be positioned；

Described ask for one and be achieved in that with the velocity error model of velocity correlation

It is provided with n geophone station, takes known focus A (x_a,y_a,z_a), calculate focus A by formula (3) and arrive The calculating whilst on tour of each geophone station is T_i ^A,

${T_i}^A=\frac{l_i^A}{v}---\left(3\right)$

Wherein, T_i ^AFor the calculating whilst on tour of focus A to i-th geophone station,For focus A to i-th detection The distance of point, v is spread speed, then the velocity error model at i geophone station is:

${\mathrm{\ϵ}}_i=\frac{{T_i}^A}{t_i^A}---\left(6\right)$

WhereinThe observation whilst on tour of i-th geophone station, ε is traveled to for focus A_iFor the speed at i geophone station Degree error rate,

Described velocity error model is applied in object function, then scans all possible hypocentral location, Finding the coordinate of the minimum point of the value making object function is exactly that the coordinate of focus to be positioned is achieved in that

Any one focus to be positioned is handled as follows:

(1) from the observation whilst on tour of this focus to each geophone station, minimum observation whilst on tour, this minimum are found Observation geophone station corresponding to whilst on tour is set to geophone station K, then calculates the sight to each geophone station of this focus Surveying whilst on tour and this focus time difference observed between whilst on tour to geophone station K, this time difference is observation trip The row time difference；

(2) in given scope, according to described velocity error model and formula (5), each shake is calculated Source to the calculating whilst on tour of each geophone station, and ask for each focus to each geophone station calculating whilst on tour with Each focus is to the time difference calculated between whilst on tour of geophone station K, and this time difference is calculating travel-time difference,

$T_i=\frac{l_i}{{\mathrm{v\ϵ}}_i}---\left(5\right)$

Wherein, T_iRepresent the focus calculating whilst on tour to i-th geophone station, l_iRepresent that focus is examined to i-th The distance of wave point；

(3) the calculating travel-time difference that the observation travel-time difference obtained with step (1) and step (2) obtain it Between the quadratic sum of difference be object function, the institute in traversal given range a little, makes the value of described object function The coordinate of minimum point is the coordinate of focus to be positioned.