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題名 | 非水平基準面擬似譜法逆時移位技術研究「重合後」=Nonflat Datum Pseudospectral Reverse Time Migration(Post-Stack) |
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作者 | 徐祥宏; 李重毅; 宣大衡; | 書刊名 | 探採研究彙報 |
卷期 | 21 1998.11[民87.11] |
頁次 | 頁137-144 |
分類號 | 457.2 |
關鍵詞 | 重合後深度移位; 非水平基準面擬似譜法重合後逆時移位; 靜態修正; 浮動基準面; Post-stack depth migration; Nonflat datum pseudospectral reverse time migration; Static correction; Floating datum; |
語文 | 中文(Chinese) |
中文摘要 | 當地下構造形貌複雜具有顯著橫向速度變化時,傳統重合後時間移位之成像無法 適應橫向之速度變化,因此經重合後時間移位之震波影像,存在有某種程度之失真,相對地 ,於此情形下,配合可靠之地層震波速度,重合後深度移位可提供更準確之地下震波影像, 逆時移位為一高適性之深度移位技術,對於地層傾角較大,速度對比較強烈之複雜地下構造 ,逆時移位之應用具有相當之可適性,重合後逆時╱深度移位係利用最終重合剖面進行移位 處理, 傳統 CMP 重合處理之主要目的即是在獲得品質足敷所需之最終重合剖面,而靜態修 正是陸上震測資料一重要之前處理,由於麓山帶地區不僅地下構造較為複雜,其地表地形之 起伏變化亦較大,因此傳統靜態修正會有所缺失產生,浮動基準面靜態修正法可大幅改進此 缺失,然而浮動基準面為一不規則之基準面,對在此不規則之基準面上所得之最終重合剖面 進行深度移位處理時,此一非水平基準面會引進數值計算上之困擾,本文參考有關理論與方 法,自行發展與建立非水平基準面擬似譜法重合後逆時移位技術,經由多種含不規則基準面 地質模型之合成震波資料測試結果,顯示此非水平基準面重合後逆時移位技術具有相當良好 之準確度與可靠性,可配合浮動基準面靜態修正法作為麓山帶震測資料重合後深度移位處理 之用。 |
英文摘要 | Imaging of conventional post-stack time migration can not accommodate itself to lateral velocity variations. Thus the seismic image obtained from conventional post-stack time migration contains distortion to certain degree, as the structural geometry of the subsurface is complicated to have remarkable lateral velocity variations. To the contrary, by combining with reliable seismic velocities of strata post-stack depth migration can provide more accurate seismic image of the subsurface in the abovementioned case. Revere time migration is a robust depth migration technique. The application of reverse time migration is fairly suitable for complex structures with steeper dips and stronger velocity contrasts. The final stack sections are migrated by the post-stack reverse time/detph migration. The main objective of the conventional CMP stacking processing is to obtain the final stack section with enough quality. Static correction is an important preprocessing for onshore seismic data. In foothill areas not only structures in the subsurface are more complex but also topographic reliefs on the surface are more severe. Therefore the conventional static correction will yield drawbacks. The floating datum static correction can greatly correct the drawbacks. Because floating datum is an irregular datum, this nonflat datum will introduce numerical problems for depth migration of the final stack section obtained on it. According to the related theories and methods, a technique of nonflat datum pseudospectral post-stack reverse time migration has been developed and established. From migration tests of synthetic data of various geological models, the results reveal that this nonflat datum post-stack reverse time migration technique has fairly good accuracy as well as reliability, and can combine with floating datum static correction to be used as post-stack depth migration of seismic data in foothill areas. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。