SEISMIC PROCESSING OF UMIAT BASIN, ALASKA

Abstract

Seismic survey plays an important role in exploration of oil and gas. It stands miles ahead of various other methods that are used to resolve the interior of the earth in terms of expenditure as well as accuracy, resolution and penetration. The main aim of seismic survey is to produce detailed images of subsurface of the earth resembling with the geological structure beneath the Earth's surface and use this information for exploration of oil and gas. It is a method of prospecting that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. This method is used for a detailed study of the subsurface of Umiat Basin. Umiat basin is located in North Slope, Alaska and has Prudhoe Bay Oil Field nearby making this basin a prospect for oil and gas accumulation. The stratigraphy of the basin consists of many shale sequences like Kingak Shale, pebble shale unit, Hue Shale and many more which can act as the source rock for oil and gas generation. Moreover, the tectonic and orogenic setting of the basin is suitable for migration and trapping of oil. Thus, five profiles of seismic data were chosen for processing in Paradigm software to get a zero-offset section of each of the profile. For processing of seismic data, many of the processes were carried out including editing, muting, geometry definition, ground roll removal, amplitude scaling, f-k filtering and deconvolution to remove the noise as much as possible and get the best out of the given data. Next, Velocity picking was done in CDP domain in order to get stacked section. Finally, Migration was carried out to remove diffraction hyperbola and multiples as well as to translate the reflection events to their original position. Some touch-up of data was done using post-processing modules. Zero-offset sections were obtained after carrying out all the above mentioned processes. The sections show that there are indeed some of anticlinal structures which can act as a trap to oil.