• Geophysics and Geophysical Exploration
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• v.5 no.3
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• pp.145-149
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• 2002

The static correction, which is classified into refraction based static correction and reflection based residual static correction, removes distortions caused by irregularities of thickness or velocity in near-surface. Generally, refraction statics is a time consuming process because of high dependence on the interpreter's analysis. Therefore, for huge 3D seismic data, automatic static correction which minimizes the interpreter's analysis is required. In this research, we introduce an efficient method of refraction static correction for land 3D seismic survey.

• 한국지구물리탐사학회:학술대회논문집
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• 2009.05a
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• pp.73-87
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• 2009

Geophysical survey for unconformity-type uranium deposit applied to this study area in Athabaska Basin, Canada were carried out airborne TEM and magnetic, resistivity-induced polarization (DC-IP), puser seismic reflection and well-logging method. The results of airborne survey interpreted the lithological boundary, geological structures, and conductors. Also, these results decided to main targets for ground DC-IP survey. The Low resistivity and the high chargeability slices of 3D modeling interpreted from DC-IP survey response for conductors related to hydrothermal alteration zones and fault-controlled graphitic zones occurring at the unconformity-type uranium deposit, and they confirmed by diamond drilling. Seismic results interpreted to lake bottom surface, alluvium layer and intra-sandstone faults. We suggest the resonable field data acquisition of DC-IP method on the land or the lake in Athabaska Basin.

• Economic and Environmental Geology
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• v.9 no.1
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• pp.1-11
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• 1976

It is believed that geological survey, drilling and geophysical survey which was carried out on Tertiary deposits in Pohang is a valuable but through the studying of many Tertiary sediments in Japan discovered many questions on analysis of final report prepared by National geological survey. The main reason is: 1. The seismic sound velocity which have regulated in the final report prepared by geological survey for Tertiary deposits in Pohang was 1,500-2,000m/sec in spite of oil bearing sediments of same age in Japan are 2,000-3,800m/sec. These may means the requirement of reconsideration of seismic velocity for Tertiary deposits in Pohang and required to have a dipper drilling. 2. Stratigraphically, geophysically, and paleontologically, the Tertiary deposits in Pahang land area is similar with that of Nishiyama-Hunakawa formations of Akita oil field in Japan. Nishiyama-Hunakawa formation is the main oil bearing formation in Japan. 3. Those valcanic rock including andestitic rock and liparitic rock which have extensively distributed over either at land area or at sea bottom, assumed by geological survey as the base of Tertiary sediments. But in case of Japan many oil bearing deposits are in over laid by these kind of volcanic rock. Therefore a possible of same condition with Japan is presumable on Tertiary sediments in Pohang. 4. It is believed that the Tertiary sediments of land area in Pohang is the extension of offshore basin but is wandering that the final report submitted by geologic survey have not remain any word on report of ECAFE discribed so much problematics as followed: A. Although it was assumed that no great thickness exceeding 1,000 meters, or major structures would be encountered in the Tertiary offshore sequence, it was hoped that shallow hydrocarbon deposits might be found, because these sediment are lithologically similar to those of the same age in the producing area of the northwest Honshu region of Japan where hydrocarbon are extracted from depths of only 500 to 600 meters. B. Four possible hydrocarbon trap conditions are represented in the survey area: anticlinal folds, faults, pinch outs, along the igneous basement and lateral facies changes. C. Most of the prime possible reservoir area are beyond the 50 meter water depth mark, except for the structures in Yonil Bay. D. Despite the shallowness of the offshore basin, sufficient trap condition exist in the area to warrant further exploration for hydrocarbon. 5. All of the problems mentioned above have gave us a strong reasons to have us hesitating to make a final conclusion on Tertiary problems in Pohang, before to have a drill to a depth to 3,000 meters or more whatever it is the Tertiary or a Mesozoics below 1,000 meters.