本文選題：繞射波分離 + 繞射目標(biāo)成像　； 參考：《中國(guó)石油大學(xué)(華東)》2015年碩士論文

【摘要】：隨著對(duì)構(gòu)造、巖性油氣藏的精細(xì)勘探和進(jìn)一步開發(fā),地下復(fù)雜構(gòu)造尤其是小尺度地質(zhì)體的高分辨率成像作為高精度地震解釋的重要前提,在油氣勘探中的作用日益顯著。作為當(dāng)前地震解釋的主要目標(biāo),斷層、尖滅、河道、裂縫、鹽丘邊界以及碳酸鹽巖縫洞儲(chǔ)集體等地質(zhì)構(gòu)造在地震剖面上通常表現(xiàn)為豐富的繞射地震響應(yīng)。然而,常規(guī)地震處理技術(shù)將鏡面反射波作為主要研究對(duì)象,繞射波往往被忽略或者視為干擾噪音濾除;即使將其偏移歸位,能量較弱的繞射波成像結(jié)果也會(huì)被強(qiáng)反射能量淹沒。由于在處理過程中丟失了繞射波所攜帶的高分辨率信息,常規(guī)地震處理得到的成像分辨率較低。因此,充分利用地震資料中的繞射波信息,實(shí)現(xiàn)繞射波單獨(dú)成像,提高小尺度地質(zhì)目標(biāo)體的成像分辨率及識(shí)別精度對(duì)于復(fù)雜地質(zhì)條件下的高精度地震解釋具有非常重要的研究意義和社會(huì)價(jià)值。本文通過分析繞射波在不同地震道集中的響應(yīng)特征,對(duì)繞射波分離關(guān)鍵技術(shù)進(jìn)行研究,提出了針對(duì)繞射波的高分辨率地震成像技術(shù),進(jìn)而服務(wù)于復(fù)雜地質(zhì)條件下的高精度地震解釋。本文首先介紹了傾角域繞射波分離與成像方法,主要包括以下幾個(gè)方面:(1)依據(jù)高斯束角度域疊前偏移思路,推導(dǎo)并實(shí)現(xiàn)了傾角域共成像點(diǎn)道集(CIG)的提取;(2)實(shí)現(xiàn)了基于相似譜掃描的傾角域繞射波分離方法,該方法可在傾角域較好的壓制反射同相軸穩(wěn)相頂點(diǎn)附近用于相干疊加的反射能量,得到的繞射波單獨(dú)成像結(jié)果可有效突出繞射能量,進(jìn)而提高繞射目標(biāo)的成像分辨率;(3)針對(duì)基于相似譜掃描的繞射波提取算法在壓制反射頂點(diǎn)附近的反射能量時(shí),反射切除半徑只能是固定值,影響波場(chǎng)分離效果,提出了基于反射能量預(yù)測(cè)的傾角域繞射波提取方法,該方法可在很好保留繞射波的前提下最大限度的壓制反射波,最終繞射波單獨(dú)成像結(jié)果的分辨率和精度都進(jìn)一步提高。鑒于傾角域繞射波分離方法對(duì)低信噪比資料的適應(yīng)性不足等缺點(diǎn),提出了基于反穩(wěn)相濾波的繞射波分離與成像方法,該方法通過在傳統(tǒng)的克希霍夫偏移算子中引入反穩(wěn)相濾波器,使?jié)M足Snell定律的鏡面反射波得到有效壓制,實(shí)現(xiàn)繞射波的提取。數(shù)值試算證明該繞射波提取方法對(duì)斷階等小尺度繞射目標(biāo)具有更好的分辨能力,成像精度更高。另外,針對(duì)邊界繞射波特有的極性反轉(zhuǎn)現(xiàn)象,在繞射波成像過程中引入極性校正因子,可以使邊界繞射波完全收斂,進(jìn)而提高斷階邊界的識(shí)別精度。
[Abstract]:With the fine exploration and further development of structures and lithologic reservoirs, the high-resolution imaging of complex underground structures, especially small scale geological bodies, as an important prerequisite for high-precision seismic interpretation, plays an increasingly important role in oil and gas exploration. As the main target of seismic interpretation at present, geological structures such as faults, pinches, river channels, fractures, salt dome boundaries and carbonate fractures and caverns are usually characterized by abundant diffraction seismic responses on seismic profiles. However, conventional seismic processing technology takes specular reflection as the main object of study. Diffraction waves are often ignored or regarded as interference noise filtering, and even if they are shifted back, the imaging results of weak diffraction waves will be submerged by strong reflection energy. Due to the loss of high resolution information carried by diffraction waves in the process of processing, the imaging resolution of conventional seismic processing is relatively low. Therefore, we can make full use of the diffraction wave information in seismic data to realize the imaging of diffraction wave separately. It is of great significance and social value to improve the imaging resolution and recognition accuracy of small scale geological objects for high-precision seismic interpretation under complex geological conditions. By analyzing the response characteristics of diffraction wave in different seismic trace concentration, the key technology of diffraction wave separation is studied in this paper, and a high resolution seismic imaging technique for diffraction wave is proposed. Then it can be used for high precision seismic interpretation under complex geological conditions. In this paper, we first introduce the method of obliquity domain diffraction wave separation and imaging, including the following aspects: 1) according to the prestack migration of Gao Si beam angle domain, The extraction of common imaging point gathers in dip domain is derived and realized. (2) the method of diffraction wave separation in dip domain based on similar spectrum scanning is realized. This method can be used to suppress the reflection energy of coherent superposition near the vertex of coaxial stable phase in the obliquity domain, and the diffraction wave imaging results can effectively highlight the diffraction energy. Then the imaging resolution of diffraction target is improved. (3) for the diffraction wave extraction algorithm based on similar spectral scanning, when the reflection energy near the reflection point is suppressed, the reflection cutting radius can only be a fixed value, which affects the separation effect of the wave field. Based on the prediction of reflection energy, an obliquity domain diffraction wave extraction method is proposed. The method can suppress the reflected wave in maximum extent on the premise of keeping the diffraction wave well, and the resolution and accuracy of the individual imaging result of the diffraction wave are further improved. In view of the inadaptability of the obliquity domain diffraction wave separation method to the low signal-to-noise ratio (SNR) data, a method of diffraction wave separation and imaging based on inverse stable phase filtering is proposed. By introducing an inverted phase filter into the traditional Kirchhoff migration operator, the mirror reflection wave satisfying Snell's law can be effectively suppressed and the diffraction wave can be extracted. Numerical results show that the proposed method has better resolution ability and higher imaging accuracy for small scale diffraction targets. In addition, the polarity correction factor is introduced in the imaging process of diffraction wave, which can make the boundary diffraction wave converge completely and improve the recognition accuracy of broken order boundary.
【學(xué)位授予單位】：中國(guó)石油大學(xué)(華東)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P631.4;P618.13

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本文編號(hào)：1899205