阅读说明：本技术 一种基于时间推移技术的地面磁共振反演方法 (A kind of ground magnetic resonance inversion method based on time lapse technique ) 是由 蒋川东 王�琦 田宝凤 易晓峰 郜泽霖 魏晋 杨雨桥 于 2019-08-13 设计创作，主要内容包括：本发明为一种基于时间推移技术的地面磁共振反演方法。该方法包括：每隔固定时间t,进行一次地面磁共振测量,得到t<Sub>1</Sub>,t<Sub>2</Sub>,…,t<Sub>N</Sub>时间对应共测量得到N组三维地面磁共振数据；对第一次测量t<Sub>1</Sub>时间对应得到的三维地面磁共振信号进行QT反演,得到含水量；按照测量的时间顺序,分别对t<Sub>2</Sub>～t<Sub>N</Sub>次测量得到的三维地面磁共振信号进行反演,在对时间t<Sub>n</Sub>测量数据反演时,将t<Sub>n-1</Sub>得到的含水量结果作为先验约束信息,以实现时间推移QT反演；最终得到的三维地面磁共振信号进行反演的结果,得到不同测量时间对应的含水量。发明提出将上一测量时间的反演结果作为该测量时间的先验约束信息,利用多个不同测量时间反演结果,描绘地下水随时间的变化情况,实现地下水的监测。(The present invention is a kind of ground magnetic resonance inversion method based on time lapse technique.This method comprises: carrying out a ground magnetic resonance measurement every set time t, obtaining t 1 ,t 2 ,…,t N Time, corresponding measurement altogether obtained the three-dimensional ground MR data of N group；T is measured to first time 1 Time, corresponding obtained three-dimensional ground magnetic resonance signal carried out QT inverting, obtained water content；According to the time sequencing of measurement, respectively to t 2 ~t N The secondary obtained three-dimensional ground magnetic resonance signal that measures carries out inverting, to time t n When measurement data inverting, by t n‑1 Obtained water content result is as prior-constrained information, to realize that the time elapses QT inverting；Finally obtained three-dimensional ground magnetic resonance signal carry out inverting as a result, obtaining the corresponding water content of different time of measuring.Invention proposes using the inversion result of a upper time of measuring as the prior-constrained information of the time of measuring, using multiple and different time of measuring inversion results, describes underground water and changes with time situation, realize the monitoring of underground water.)

1. a kind of ground magnetic resonance inversion method based on time lapse technique, which is characterized in that this method comprises:

Every set time t, a ground magnetic resonance measurement is carried out, t is obtained₁,t₂,…,t_NTime, corresponding measurement altogether obtained N group Three-dimensional ground MR datat_nWhen indicating that n-th three-dimensional measurement is corresponding Between, n=1,2 ..., N；

T is measured to first time₁Time, corresponding obtained three-dimensional ground magnetic resonance signal carried out QT inverting, obtained water content For the water content of corresponding k-th of the unit of first time measurement result；

According to the time sequencing of measurement, respectively to t₂~t_NThe secondary obtained three-dimensional ground magnetic resonance signal that measures carries out inverting, right Time t_nWhen measurement data inverting, by t_n-1Obtained water content result is as prior-constrained information, to realize that time passage QT is anti- It drills；

T is measured according to first time₁Time, corresponding obtained three-dimensional ground magnetic resonance signal carried out QT inversion resultAnd t₂~ t_NIt is secondary to measure that obtained three-dimensional ground magnetic resonance signal carries out inverting as a result, obtaining the corresponding water content of different time of measuring

2. according to the method for claim 1, which is characterized in that measurement t₁The ground MR data of timeInverting Shown in objective function such as formula (1):

Wherein C_VFor the covariance of MR data error,For modelCorresponding forward modeling is as a result, λ₁It is thick for model The corresponding regularization factors of rugosity, roughness matrix of the C between the adjacent 3 subdivision units of Earth model:

3. according to the method for claim 2, which is characterized in that

t₂~t_NThe ground MR data that time measurement obtainsInversion objective function such as formula (2) shown in:

Wherein C_TFor prior information diagonal matrix, diagonal entry C_T(i,i)For the variance of the corresponding uncertainty of i-th of prior information, λ₂Corresponding regularization factors, n value are as follows: 2~N are constrained for time passage.

4. according to the method for claim 1, which is characterized in that solve formula (1) and formula (2) obtains different time of measuring and corresponds to Water content

Technical field

The invention belongs to Geophysical Data Processing and inversion interpretation fields, specifically elapse skill based on the time for one kind The ground magnetic resonance inversion method of art.

Background technique

Geophysical method of the ground magnetic resonance as a kind of direct quantitative evaluation of subterranean water-bearing layer Hydrological characteristic parameter, mesh Before have been widely used in fwaater resources protection and underground disaster water source exploration.But at present it is simple two dimension, 3-d inversion Method, inversion result can not describe underground water and change with time, and cannot achieve the monitoring to underground water, therefore research is based on The time ground magnetic resonance inversion method of passage is of great significance.

CN103984033A discloses a kind of ground nuclear magnetic resonance two-dimensional inversion method.This method utilizes Stacking Transformation method Two-dimentional forward model is subjected to dimension-reduction treatment, is abstracted as matrix equation solving model, and with least square singular value decomposition Inverting solution is carried out with the red method combined of improved stochastic gradient descent method, to realize two dimensional inversion, this method is single The inversion result of one time measurement data.

CN108897051A discloses a kind of high-resolution ground nuclear magnetic resonance imaging method.This method applies wave first Field transformation obtains each receiving coil on survey line and intends seismic wave field discrete data, and intends seismic wave to receiving coil each on survey line Field discrete data seeks deconvolution, eliminates the pulse width effect of wave field transformation.Secondly by reference point each within the scope of synthetic aperture Superposition improves detection signal-to-noise ratio, obtains the virtual seismic wave occasion of synthetic aperture on survey line into value.It is finally inclined using kirchhoff Imaging theory is moved, solves and intends seismic wave equation, realization underground water-bearing structure migration imaging, but the inverting that this method obtains As a result it can not describe underground water to change with time, cannot achieve the monitoring to underground water.

CN105785455A discloses a kind of two-dimentional ground nuclear magnetic resonance inversion method based on B-spline interpolation.This method It is laid with less coil, only acquires the signal of several measuring points, in conjunction with the inversion method of spline interpolation, is obtained with array coil The obtained explanation results of half mulching are suitable for non-laminar uneven water body detection.

This method solve two dimensional NMR detection wiring time is long, the low problem of detection efficient, but this method is still It so cannot achieve the monitoring to underground water.

Summary of the invention

Technical problem to be solved by the present invention lies in provide a kind of ground magnetic resonance inverting based on time lapse technique Method can describe underground water and change with time situation, realize the monitoring of underground water.

The invention is realized in this way

A kind of ground magnetic resonance inversion method based on time lapse technique, which is characterized in that this method comprises:

Every set time t, a ground magnetic resonance measurement is carried out, t is obtained₁,t₂,…,t_NTime, corresponding measurement altogether obtained The three-dimensional ground MR data of N groupt_nIndicate that n-th three-dimensional measurement is corresponding Time, n=1,2 ..., N；

T is measured to first time₁Time, corresponding obtained three-dimensional ground magnetic resonance signal carried out QT inverting, obtained water content For the water content of corresponding k-th of the unit of first time measurement result；

According to the time sequencing of measurement, respectively to t₂~t_NThe secondary obtained three-dimensional ground magnetic resonance signal that measures carries out inverting, To time t_nWhen measurement data inverting, by t_n-1Obtained water content result is as prior-constrained information, to realize that the time elapses QT inverting；

T is measured according to first time₁Time, corresponding obtained three-dimensional ground magnetic resonance signal carried out QT inversion resultAnd t₂~t_NIt is secondary to measure that obtained three-dimensional ground magnetic resonance signal carries out inverting as a result, to obtain different time of measuring corresponding aqueous Amount

Further, t is measured₁The ground MR data of timeInversion objective function such as formula (1) shown in:

Wherein C_VFor the covariance of MR data error,For modelCorresponding forward modeling is as a result, λ₁For mould The corresponding regularization factors of type roughness, roughness matrix of the C between the adjacent 3 subdivision units of Earth model:

Further, t₂~t_NThe ground MR data that time measurement obtainsInversion objective function such as formula (2) institute Show:

Wherein C_TFor prior information diagonal matrix, diagonal entry C_T(i,i)For the corresponding uncertainty of i-th of prior information Variance, λ₂Corresponding regularization factors, n value are as follows: 2~N are constrained for time passage.

Further, formula (1) and formula (2) are solved and obtains the corresponding water content of different time of measuring

Compared with prior art, the present invention beneficial effect is:

The present invention is based on the ground magnetic resonance inversion methods of time lapse technique, it is intended to be based on time lapse technique, propose Using the inversion result of a upper time of measuring as the prior-constrained information of the time of measuring, multiple and different time of measuring invertings are utilized The situation as a result, description underground water changes with time, realizes the monitoring of underground water.

Detailed description of the invention

Fig. 1 is the flow chart of the ground magnetic resonance inversion method based on time lapse technique；

Fig. 2 is that the 1st hour measurement obtains magnetic resonance number based on the ground magnetic resonance signal inversion result (a) that the time elapses According to inversion result (b) be the inversion result (c) that the 3rd hour measurement obtains MR data be that the 5th hour measurement obtains The inversion result of MR data；

QT inverting (conventional method) result (a) of the ground Fig. 3 magnetic resonance signal is that the 1st hour measurement obtains magnetic resonance number According to inversion result (b) be the inversion result (c) that the 3rd hour measurement obtains MR data be that the 5th hour measurement obtains The inversion result of MR data.

Specific embodiment

In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to embodiments, to the present invention It is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not used to Limit the present invention.

Shown in Figure 1, a kind of ground magnetic resonance inversion method based on time lapse technique, this method includes,

Step 1: ground magnetic resonance tool and three-dimensional battle array are utilized every one section of regular time t in same experiment place Column measurement method carries out one-shot measurement, by time t_NAfter=N × t, t₁,t₂,…,t_NTime, corresponding measurement altogether obtained N group three Ground magnetic resonance signal is tieed up,t_nIndicate the n-th three-dimensional measurement corresponding time, N=1,2 ..., N.

Step 2: t is measured to first time first₁Time, corresponding obtained three-dimensional ground magnetic resonance signal carried out QT inverting, Obtain water content For the water content of corresponding k-th of the unit of first time measurement result.Secondly According to the time sequencing of measurement, respectively to t₂~t_NThe secondary obtained three-dimensional ground magnetic resonance signal that measures carries out inverting, to the time t_nWhen measurement data inverting, by t_n-1Obtained water content result is as prior-constrained information, to realize that the time elapses QT inverting. Finally obtain the corresponding water content of different time of measuring

Measure t₁The ground MR data of timeInversion objective function such as formula (1) shown in:

Wherein C_VFor the covariance of MR data error,For modelCorresponding forward modeling is as a result, λ₁For The corresponding regularization factors of model roughness, roughness matrix of the C between the adjacent 3 subdivision units of Earth model:

t₂~t_NThe ground MR data that time measurement obtains(refer to t₂~t_NThe a certain group of number that time measurement obtains According to) inversion objective function such as formula (2) shown in:

Wherein C_TFor prior information diagonal matrix, diagonal entry C_T(i,i)For the corresponding uncertainty of i-th of prior information Variance, λ₂Corresponding regularization factors, n value are as follows: 2~N are constrained for time passage.

The corresponding water content of different time of measuring can be obtained in solution formula (1) and formula (2)