英文篇名
Geological Advisor, Occidental International Exploration and Production Company
作者
牟敦堅
摘要
反射震測學(Reflection Seismology)自從J.C.Karcher在一九一九年申請其發明專利權以來,七十年中,由於石油與天然氣探勘和開發對此科學之依賴與需求,不斷的研究發展,在技術上創造了無數次重大的突破(Allen,1980)。其重要功能也從早年的僅僅能提供一些地下地質構造的模糊輪廓,到近年來使用各種高解析度的震測資料,讓地質工作者不但可以清晰的看到地下數米至數千米深處的斷層與構造,還能夠藉著其中蘊藏的豐富地質情報,做出許多極具實用性的地層和岩性的解釋。
雖然到目前為止,反射震測絕大部份是應用在油氣探勘及採油工程上,但是隨著高解析度震測技術的進展,和小型電腦處理大量資料能力的提昇及成本的降低,從事一般道路、橋樑、港灣等重大建設,以及地下水保育、開發,廢料和污染物堆棄等等的工程人員,也逐漸開始嘗試運用反射震測來獲取種種不同的地下地質資料。以往工程地質人員多只能依賴地表的露頭和地下的鑽孔來提供這類資料給工程單位,然而由有限的採樣點做出的地質解釋,不但需要耗費可觀的時間與金錢,遇到地質稍微複雜或多為風化沈積物所覆蓋的區域時,甚至往往無法預測出正確的地質全貌。反之,反射震測在海上和地形不很崎嶇的陸地上(如沈積盆地或沖積平原),短時間內不但可以收集大量的反射資料,更重要的是,這種由線聯結成面的資料,配合上少許關鍵位置的鑽孔和正確的地質解釋,還能讓整個區域的地質狀況詳細的呈現在地質與工程人員的眼前。在重大工程施工以前如果能夠對施工區域的地質預先有了全盤的掌握,工程師們方可做出周密的計畫及正確的成本評估,進而在施工當中得以迴避開各種可能遭遇的問題,節約下可觀的開支,加速工程的進度,而且能夠確定工程在完工以後,不易於受到自然災害的破壞,其對地質環境的影響也被減至最低程度。
英文摘要
Advances in reflection seismology have continued during the last several decades at a rather rapid pace. Numerous technological breakthroughs were developed originally to meet the needs from the petroleum industry, but in recent years the number of uses of engineering seismology has grown tremendously. Applications now include studies of pipeline and highway routings, and site selections for dams, power plants(nuclear or otherwise), high-rise buildings, tunnels, subways, sewage plants, underground waste disposal, water or petroleum storage facilities, and utilization and conservation of groundwater resources.
Adequately processed, multi-fold reflection seismic can provide a large amount of useful geological information in the subsurface. By correct interpretation, various types of physical characters of reflections, such as velocity, amplitude, phase, frequency, continuity, and geometry, can be translated into lithology, depositional environment, porosity, rock hardness, fluid content, as well as structural information like faulting and bed dipping angle. Good understanding of the subsurface geology before and during any engineering project will in turn warrant a trouble-free and cost-efficient operation from the planning till the end.