本文選題：OBS + 多次波�。� 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：隨著海上油氣勘探的發(fā)展,過(guò)去的地震采集技術(shù)已經(jīng)很難滿足當(dāng)下人們對(duì)油氣開(kāi)采的需求,OBS作為新的地震采集技術(shù)引起了廣泛的關(guān)注。不論是在利用拖纜數(shù)據(jù)采集還是利用OBS地震數(shù)據(jù)采集方法,海上油氣勘探中的多次波問(wèn)題始終是地震數(shù)據(jù)處理的關(guān)鍵技術(shù)之一。經(jīng)過(guò)研究發(fā)現(xiàn)多次波與一次波一樣攜帶了大量的地下信息,尤其是在構(gòu)造復(fù)雜地區(qū),多次波數(shù)據(jù)卻能夠更好的成像。在OBS(海洋地震儀)勘探中,由于是將OBS置于海底,并且其每個(gè)OBS的間隔通常是大于200米的,在利用常規(guī)一次波進(jìn)行偏移成像時(shí),其海底淺層的成像受海底異常體影響大,成像效果很糟糕。然而,我們利用多次波進(jìn)行成像時(shí),不僅能夠獲得較為寬廣的照明,對(duì)海底能夠進(jìn)行很好的成像,并且能夠有利于淺層地區(qū)的成像,獲得較好的偏移效果。尤其是在OBS數(shù)據(jù)缺失的時(shí)候,由于多次波旅行時(shí)較長(zhǎng),受海底異常體影響小,能夠獲得比一次波更加可靠連續(xù)的成像結(jié)果。因此,我們?cè)谒衔锟碧交蛘呤呛５追�(wěn)定性研究時(shí),利用多次波成像的特點(diǎn),可以為我們更好的完成地球物理調(diào)查任務(wù)。就利用多次波數(shù)據(jù)提高成像精度的方法研究而言,本次論文主要從OBS多分量數(shù)據(jù)的波場(chǎng)分離、射線追蹤速度建模、逆時(shí)偏移三個(gè)方面入手來(lái)實(shí)現(xiàn)。首先介紹了OBS的勘探原理以及多次波的識(shí)別與衰減,然后介紹了逆時(shí)疊前深度偏移的原理及實(shí)現(xiàn),最后利用射線追蹤建立速度模型并實(shí)現(xiàn)了逆時(shí)偏移。在研究的過(guò)程中先探討了的一次波與多次波在理論模型中逆時(shí)疊前深度偏移的結(jié)果,再對(duì)影響成像精度的因素進(jìn)行了探討,對(duì)比分析了一次波和多次波的成像結(jié)果,最后研究了由于OBS的位置和子波的頻率或延遲等對(duì)多次波成像結(jié)果所造成的的影響。經(jīng)過(guò)理論模型與實(shí)測(cè)數(shù)據(jù)的研究,我們發(fā)現(xiàn)其利用多次波數(shù)據(jù)確實(shí)能夠提高海底淺層的成像,有利于我們水合物的勘探,且逆時(shí)偏移能夠在大傾角處成像比單程波更具有優(yōu)勢(shì)。逆時(shí)偏移方法能夠適應(yīng)于OBS特殊的觀測(cè)系統(tǒng),它不需要保證炮點(diǎn)和檢波點(diǎn)在同一基準(zhǔn)面上,成像更具有靈活性。
[Abstract]:With the development of offshore oil and gas exploration, the past seismic acquisition technology has been difficult to meet the current demand for oil and gas production. As a new seismic acquisition technology, OBS has attracted wide attention.Whether using towed cable data acquisition or OBS seismic data acquisition method, the multiple wave problem in offshore oil and gas exploration is always one of the key techniques of seismic data processing.It is found that multiple waves carry a lot of underground information just like primary waves, especially in complex structures, but multiple data can be better imaged.In ocean seismograph exploration, because the OBS is placed on the seabed and the interval of each OBS is usually more than 200m, the imaging of the shallow layer of the seabed is greatly affected by the seabed anomaly when the conventional primary wave is used for migration imaging.The imaging is very poor.However, when we make use of multiple waves, we can not only obtain broad illumination, but also make good imaging of the seabed, which is beneficial to the imaging of shallow area and obtain better migration effect.Especially in the absence of OBS data, because of the long travel time of multiple waves and the small influence of seafloor anomaly, we can obtain more reliable and continuous imaging results than the first wave.Therefore, in hydrate exploration or submarine stability research, we can make use of the characteristics of multiple wave imaging to complete the geophysical survey for us.As far as the method of improving imaging accuracy is concerned, this paper mainly focuses on three aspects: wave field separation of OBS multi-component data, ray tracing velocity modeling and inverse time migration.This paper first introduces the exploration principle of OBS and the recognition and attenuation of multiple waves, then introduces the principle and realization of inverse time prestack depth migration. Finally, the velocity model is established by ray tracing and the inverse time migration is realized.In the course of the study, the results of the inversion prestack depth migration of the primary wave and the multiple wave in the theoretical model are discussed first, and then the factors affecting the imaging accuracy are discussed, and the imaging results of the primary wave and the multiple wave are compared and analyzed.Finally, the effects of the position of OBS and the frequency or delay of wavelet on the imaging results are studied.Through the study of theoretical model and measured data, we find that the multiple wave data can really improve the imaging of shallow seabed, which is beneficial to the exploration of hydrate, and the inverse time migration is more advantageous than the single-pass wave in imaging at large dip angle.The inverse time migration method can be adapted to the special observation system of OBS. It does not need to ensure that the shot point and the detection point are on the same datum level and the imaging is more flexible.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P631.46

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 唐文;王尚旭;;子波延遲對(duì)逆時(shí)偏移成像精度的影響[J];石油天然氣學(xué)報(bào);2012年11期

，

本文編號(hào)：1737453