Research On Pre-stack Seismic Attributes Applied In Reservoir Prediction And Hydrocarbon Detection

Based on increasingly widespread applying pre-stack seismic attributes in reservoir prediction and hydrocarbon prediction, this paper chose AVO technology which has developed more maturely to study change characteristics of reflection amplitude versus offset on pre-stack seismic gathers. Fully digging and using the non-zero offset seismic information in pre-stack seismic records, and picking up pre-stack attribute characteristics provided more extensive and reliable basis for reservoir prediction.This paper is divided into three parts. The first introduced the basic theory of AVO technology and rock physics basis which can provide solid theoretical basis for AVO forward modeling and attribute analysis. Then theoretical models were constructed and AVO forward modeling was did to discuss the different types of AVO anomalies. Referring to the AVO response of typical theoretical models we analyzed lithologic characters and physical properties of reservoirs in the key well in the actual work area, established rock physics model of reservoirs, studied fluid replacement, analyzed AVO characteristics of oil, gas and water in complex geological conditions, created the corresponding AVO detection signs, and directly identified lithology and oil and gas in actual seismic records. Moreover forward modeling and analysis of pre-stack reflection seismic response of thin-layer was carried out, and pre-stack attributes on the impact of the thin-layer thickness were studied. The second part is that using AVO attribute analysis techniques, lithologic parameters hidden in seismic information were extracted reasonably, and the attributes that be favorable for reservoirs were optimized out. For the pre-stack attributes such as intercept, gradient, Poisson's ratio and fluid factors, gas anomaly was detected by using cross plot analysis techniques. The last part is that the pre-stack elastic impedance inversion techniques were applied, and the basic idea of the inversion was described in detail. Combined with the rock physics analysis of the actual work area, modeling and the elastic impedance inversion were done. Seismic response characteristics of different lithology, physical properties, oil and gas were analyzed to look for effective reservoir distribution.This paper took the pre-stack seismic data from some low-lying in Shengli Oilfield as an example, and application of technical methods of this article has made some abnormal predictions. This shows that the ideas and analysis methods of this research had some positive significance for applying AVO analysis to complex areas.