粘聲波保幅逆時偏移方法研究
發(fā)布時間：2019-04-27 04:22
【摘要】：疊前逆時偏移以雙程波理論為基礎(chǔ),具有使地下復(fù)雜的速度場開展成像的能力,不僅對劇烈變化的速度場具有很好的適應(yīng)性,而且還能對復(fù)雜地形和陡傾角進(jìn)行成像,對復(fù)雜地質(zhì)目標(biāo)介質(zhì)(尤其是大傾角地區(qū))勘探有著重大的作用。目前地震勘探所使用的逆時偏移成像算子大部分都是在理想彈性各向同性介質(zhì)假設(shè)的條件下推導(dǎo)的,然而,地震勘探中面臨的實際地下介質(zhì)其實普遍存在著粘滯性,地震波經(jīng)過地下地層中,地下介質(zhì)并非是完全彈性介質(zhì),即使對透射損失、幾何擴(kuò)散等因素引起的衰減進(jìn)行進(jìn)行補(bǔ)償后,地震剖面里面中,深層的能量仍要弱于淺層。說明地震波在實際傳播經(jīng)過的路徑里存在能量的耗損,使得地震波的振幅發(fā)生衰減,相位產(chǎn)生畸變,使得地震資料信噪比低,深部變得模糊。因此,有必要研究基于粘聲介質(zhì)雙程波動方程理論,發(fā)展粘聲介質(zhì)逆時深度偏移方法,校正子波的空變特征,補(bǔ)償振幅衰減,以適應(yīng)實際地層地震勘探的要求。地震波成像是地震學(xué)的關(guān)鍵中間環(huán)節(jié),它前面與野外地震數(shù)據(jù)采集緊密相關(guān),后面為疊后波阻抗反演、疊前AVA/AVO反演等提供扎實的基礎(chǔ)數(shù)據(jù),對地震處理和成像的要求,不僅是把地表上記錄的反射波歸位到地下的正確位置上去,對于深度域成像,目標(biāo)是使反射系數(shù)直接歸位到它的正確深度和位置上去。還要求波的“振幅”大小與局部反射點的反射系數(shù)呈正相關(guān)關(guān)系;然后是估計地下巖石介質(zhì)的物性參數(shù),主要是速度和密度參數(shù),最終描述含油氣儲層。然而,常規(guī)逆時偏移成像往往存在低頻噪音,以及沒有補(bǔ)償?shù)卣鸩ㄔ趥鞑ミ^程中透射與反射產(chǎn)生的能量損失,還有,觀測系統(tǒng)的往往不規(guī)則,地震數(shù)據(jù)存在有限的頻帶,這都對制約著真振幅偏移成像。為了改善成像效果,實現(xiàn)保幅偏移成像,發(fā)展根據(jù)需要成像的介質(zhì)參數(shù),在反演的理論框架下建立最小二乘偏移的目標(biāo)函數(shù),并借助伴隨狀態(tài)法推導(dǎo)迭代反演算法,利用局部尋優(yōu)算子,構(gòu)建最小二乘逆時偏移的迭代反演方法,將有效提高復(fù)雜介質(zhì)條件下地質(zhì)體的成像精度,合理消除由于地層吸收、透射及幾何擴(kuò)散等作用對振幅、頻率及相位的影響作用,提高成像分辨率,改善振幅屬性,實現(xiàn)保幅、保真、高精度成像剖面�；谝陨侠碚摲治龅幕A(chǔ)上,本文基于標(biāo)準(zhǔn)線性固體粘彈性機(jī)制模型的粘聲介質(zhì)理論,實現(xiàn)粘聲介質(zhì)逆時深度偏移,并將粘聲介質(zhì)逆時偏移與最小二乘思路相結(jié)合,發(fā)展了帶有振幅補(bǔ)償?shù)恼陈暯橘|(zhì)最小二乘LSRTM。模型數(shù)據(jù)試算結(jié)果較好,驗證了粘聲介質(zhì)逆時偏移與最小二乘偏移能夠補(bǔ)償粘聲介質(zhì)對地震波吸收衰減,可以進(jìn)行保幅成像。
[Abstract]:Based on the two-way wave theory, the prestack inverse time migration has the ability of imaging the complex underground velocity field, which not only has good adaptability to the rapidly changing velocity field, but also can image the complex terrain and steep dip angle. It plays an important role in the exploration of complex geological target medium (especially in the area of large dip angle). At present, most of the inverse time migration imaging operators used in seismic exploration are derived under the assumption of ideal elastic isotropic medium. However, the actual underground medium faced by seismic exploration is generally viscous. After the seismic wave passes through the underground strata, the underground medium is not completely elastic. Even after compensating the attenuation caused by transmission loss and geometric diffusion, the energy in the deep layer of the seismic section is still weaker than that in the shallow layer. It is shown that there is energy loss in the path through which seismic wave propagates, which causes the amplitude of seismic wave to attenuate and the phase distorts, which makes the signal-to-noise ratio of seismic data low and the depth blurred. Therefore, it is necessary to develop the inverse time-depth migration method based on the two-way wave equation theory of the viscoelastic medium, to correct the spatial variation characteristics of the wavelet and compensate the amplitude attenuation in order to meet the requirements of seismic exploration in the actual formation. Seismic wave imaging is a key intermediate link in seismology, which is closely related to field seismic data acquisition in front of it, and provides solid basic data for post-stack impedance inversion, prestack AVA/AVO inversion and so on, which requires seismic processing and imaging. It is not only to relocate the reflected wave recorded on the surface to the correct position underground, but also to relocate the reflection coefficient directly to its correct depth and position for depth-domain imaging. It is also required that the amplitude of the wave is positively correlated with the reflection coefficient of the local reflection point, and then the physical parameters of the underground rock medium, mainly the velocity and density parameters, are estimated, and finally the oil-bearing reservoir is described. However, the conventional inverse time migration imaging often has low frequency noise and does not compensate for the energy loss caused by transmission and reflection of seismic waves in the process of propagation. Moreover, the observation system is often irregular and the seismic data have a limited frequency band. This is all restricted to true amplitude migration imaging. In order to improve the imaging effect and realize the amplitude-preserving migration imaging, according to the need of imaging medium parameters, the objective function of least square migration is established in the framework of inversion theory, and the iterative inversion algorithm is deduced by means of adjoint state method. By using the local optimization operator, the iterative inversion method of least square inverse time migration is constructed, which will effectively improve the imaging accuracy of geological bodies under complex medium conditions, and reasonably eliminate the amplitude due to the action of stratum absorption, transmission and geometric diffusion, etc. The influence of frequency and phase can improve imaging resolution and amplitude attribute, and realize preserving, fidelity and high precision imaging profile. Based on the above theoretical analysis, based on the viscoelastic mechanism model of standard linear solid, this paper realizes the inverse time depth migration of the viscoelastic medium, and combines the inverse time migration of the viscoelastic medium with the least square method. The least squares LSRTM. with amplitude compensation for viscoelastic media is developed. The experimental results show that the inverse time migration and least square migration of the viscoelastic medium can compensate the absorption and attenuation of seismic waves and can be used for amplitude-preserving imaging.
【學(xué)位授予單位】：中國石油大學(xué)(華東)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.4
本文編號：2466684
[Abstract]:Based on the two-way wave theory, the prestack inverse time migration has the ability of imaging the complex underground velocity field, which not only has good adaptability to the rapidly changing velocity field, but also can image the complex terrain and steep dip angle. It plays an important role in the exploration of complex geological target medium (especially in the area of large dip angle). At present, most of the inverse time migration imaging operators used in seismic exploration are derived under the assumption of ideal elastic isotropic medium. However, the actual underground medium faced by seismic exploration is generally viscous. After the seismic wave passes through the underground strata, the underground medium is not completely elastic. Even after compensating the attenuation caused by transmission loss and geometric diffusion, the energy in the deep layer of the seismic section is still weaker than that in the shallow layer. It is shown that there is energy loss in the path through which seismic wave propagates, which causes the amplitude of seismic wave to attenuate and the phase distorts, which makes the signal-to-noise ratio of seismic data low and the depth blurred. Therefore, it is necessary to develop the inverse time-depth migration method based on the two-way wave equation theory of the viscoelastic medium, to correct the spatial variation characteristics of the wavelet and compensate the amplitude attenuation in order to meet the requirements of seismic exploration in the actual formation. Seismic wave imaging is a key intermediate link in seismology, which is closely related to field seismic data acquisition in front of it, and provides solid basic data for post-stack impedance inversion, prestack AVA/AVO inversion and so on, which requires seismic processing and imaging. It is not only to relocate the reflected wave recorded on the surface to the correct position underground, but also to relocate the reflection coefficient directly to its correct depth and position for depth-domain imaging. It is also required that the amplitude of the wave is positively correlated with the reflection coefficient of the local reflection point, and then the physical parameters of the underground rock medium, mainly the velocity and density parameters, are estimated, and finally the oil-bearing reservoir is described. However, the conventional inverse time migration imaging often has low frequency noise and does not compensate for the energy loss caused by transmission and reflection of seismic waves in the process of propagation. Moreover, the observation system is often irregular and the seismic data have a limited frequency band. This is all restricted to true amplitude migration imaging. In order to improve the imaging effect and realize the amplitude-preserving migration imaging, according to the need of imaging medium parameters, the objective function of least square migration is established in the framework of inversion theory, and the iterative inversion algorithm is deduced by means of adjoint state method. By using the local optimization operator, the iterative inversion method of least square inverse time migration is constructed, which will effectively improve the imaging accuracy of geological bodies under complex medium conditions, and reasonably eliminate the amplitude due to the action of stratum absorption, transmission and geometric diffusion, etc. The influence of frequency and phase can improve imaging resolution and amplitude attribute, and realize preserving, fidelity and high precision imaging profile. Based on the above theoretical analysis, based on the viscoelastic mechanism model of standard linear solid, this paper realizes the inverse time depth migration of the viscoelastic medium, and combines the inverse time migration of the viscoelastic medium with the least square method. The least squares LSRTM. with amplitude compensation for viscoelastic media is developed. The experimental results show that the inverse time migration and least square migration of the viscoelastic medium can compensate the absorption and attenuation of seismic waves and can be used for amplitude-preserving imaging.
【學(xué)位授予單位】：中國石油大學(xué)(華東)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.4
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 吳國忱;秦海旭;;各向同性彈性波隨機(jī)邊界逆時偏移[J];地球物理學(xué)進(jìn)展;2014年04期
2 郭見樂;;基于粘滯性聲波方程的吸收補(bǔ)償方法[J];物探與化探;2014年03期
3 杜啟振;朱釔同;張明強(qiáng);公緒飛;;疊前逆時深度偏移低頻噪聲壓制策略研究[J];地球物理學(xué)報;2013年07期
4 田坤;黃建平;李振春;李娜;孔雪;李慶洋;;實現(xiàn)復(fù)頻移完全匹配層吸收邊界條件的遞推卷積方法[J];吉林大學(xué)學(xué)報(地球科學(xué)版);2013年03期
5 孫天真;谷玉田;張惠欣;劉瑞合;;基于粘聲介質(zhì)的反Q濾波疊前深度偏移方法研究[J];石油物探;2013年03期
6 張瑾;劉財;馮fE;王典;于月;;波場延拓反Q濾波的正則化方法[J];世界地質(zhì);2013年01期
7 嚴(yán)紅勇;劉洋;;Kelvin-Voigt黏彈性介質(zhì)地震波場數(shù)值模擬與衰減特征[J];物探與化探;2012年05期
8 王保利;高靜懷;陳文超;張喚蘭;;地震疊前逆時偏移的有效邊界存儲策略[J];地球物理學(xué)報;2012年07期
9 王文闖;李合群;;混合法Q吸收補(bǔ)償[J];石油地球物理勘探;2012年02期
10 龍桂華;趙宇波;李小凡;高琴;王周;;三維交錯網(wǎng)格有限差分地震波模擬的GPU集群實現(xiàn)[J];地球物理學(xué)進(jìn)展;2011年06期
，本文編號：2466684
本文鏈接：http://sikaile.net/kejilunwen/diqiudizhi/2466684.html
最近更新
教材專著
