Application Of Seismic Reservoir Prediction Techniques In KK&YY Block, Libya

In this paper, KK&YY block of Sirte Basin, which is one of the most abundant oil resources in Libya, North Africa, was taking as the object of this study. The main purpose of the paper is to be familiar with the basic petroleum geology conditions and forming rules of reservoir of this country. Giving consideration to limited information of KK&YY block, high-resolution three-dimensional seismic data is fully used in the study. Combined with a small amount of geological, logging, testing, drilling and other information, high-resolution post-stack reservoir inversion and pre-stack elastic parameter inversion are carried out to study the reservoir distribution and hydrocarbon accumulation rules. This paper, based on the studies by applying a series of geophysical techniques, tries to explore a set of practical and effective reservoir and hydrocarbon prediction methods to solve problems like quick change of clastic sandstone reservoir with less drilling data, remaining oil distribution zone to improve the prediction accuracy on reservoir and oil/gas resources.The research, based on three-dimensional high-resolution seismic data of KK&YY block, has conduct a variety of seismic attribute analysis, post-stack reservoir inversion, pre-stack elastic parameter inversion, oil and gas detection and related comprehensive study. The main contents and conclusions are listed as following.Through detailed structural interpretation and analysis on a large number of seismic attributes, it is considered that coherence slice not only can identify medium and big faults, but also can identify small faults. Waveform classification study shows that it can make qualitative forecasting on the clastic reservoir compared to traditional attribute prediction techniques, and results show that the sandstone distribution was controlled by the faults of NW-SE trending.In order to obtain high resolution reservoir inversion results, systematic analysis has been carried out on parameter optimization, wavelet optimization, data related procession and analysis, initial geological modeling, and other aspects. The target reservoir has been predicted accurately. Through comparison between well data and impedance inversion results, it shows that the post-stack inversion can make quantitative description on sandstone reservoir in the study area.Pre-stack elastic parameter inversion and seismic attenuation attribute analysis have made significant achievements on oil-bearing reservoir prediction at KK&YY block. Elastic parameters like Poisson ratio and Lame’s coefficient (λ*ρ) are very sensitive to oil/gas, meanwhile, a variety of post-stack attribute analysis shows that low frequency energy value is the only post-stack seismic attribute which is sensitive to oil/gas. The two different types of geophysical techniques have obtained close remaining oil prediction results. The compliance rate between given well and well-by perdiction results has been up to 90% and the predicted results have been confirmed by KK4-82 well.