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題名 | 震測資料重合前深度移位處理速度模型建立之研究 |
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作者 | 陳奇呈; 黃昌盛; | 書刊名 | 石油鑽採工程 |
卷期 | 39 1998.12[民87.12] |
頁次 | 頁104-124 |
分類號 | 457.2 |
關鍵詞 | 震測資料重合; 深度移位處理; 速度模型; |
語文 | 中文(Chinese) |
中文摘要 | 在地質構造簡單及側向速度變化不大地區,一般時間移位處理即可獲得令人滿意 的結果。但是當側向速度有強烈的變化時,一般時間移位甚或重合前時間移位處理便不能提 供準確的移位結果,此時便需使用重合前深度移位處理。 時間移位與深度移位的差異可用繞射模型加以說明。當速度有沿側向變化,繞射曲線頂點不 會與繞射點位置一致,時間移位處理會將能量收斂至繞射曲線頂點位置,而非實際繞射點位 置。深度移位之所以能得到較佳品質主要是它所累加之能量是沿著正確的繞射曲線,而非大 略估計之曲線,所以深度移位處理可將能量收斂至正確位置上。 重合前深度移位處理是一種以建立模型方式進行之過程,因此在剖面上選取速度層面再分析 速度建立模型,是整個處理過程最關鍵重要的部分。鑑於錯誤的地質及速度模型可能導致不 良處理結果,因此需要透過不斷的更新修正地質模型及速度模型來得到最合理的結果,亦即 所得到的深度剖面必須與速度模型與地質模型相吻合才是最正確可信的結果。重合前深度移 位實際上並非只是單純一般的資料處理而已,它也包括了部分地區解釋的成份在內,且唯有 地質解釋人員與處理人員充分合作才可得到一張具地質意義又兼具合理速度變化,可信度高 的深度剖面。 |
英文摘要 | Although time migration algorithms are accurate in most areas with mild lateral velocity variations, the situation is different when strong lateral velocity variations are encountered. In that case, time migration algorithms no longer provide adequate accuracy and pre-stack depth migration, rather than post-stack time migration, must be done. The main difference between time and depth migration is in the way lateral velocity variations are handled. Time migration does not handle the lateral velocity variations correctly, while depth migration attempts to work accurately in these circumstances. They differ in image quality and lateral positioning. Better focusing is achieved through depth migration, which sum energy along the true curve rather than an approximate curve. When the velocity varied laterally, the apex of the diffraction point does not coincide with the diffraction point. Time migration positions the image at the apex, thus laterally mispositioning the event. Depth migration positions the event correctly. Pre-stack depth migration is a model-base approach to integrated interpretation and analysis. One should interactively evaluate the process using model verification procedures and refine velocity model parameters until the optimal solution is obtained. This model base imaging approach that represents a full integration of geology and geophysics is a parallel method intimately binds the interpretation and processing steps. This approach can produce reliable and accurate results because it cvreates the most accurate earth models, representing subsurface structure as well as velocity. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。