关键词: 薄互层, 火成岩, 地震响应, 厚度预测, 古近系, 渤海地区

Abstract: Igneous rocks are widely developed in Paleogene in B oilfield of Bohai Sea area. The igneous rocks dominated by eruption mainly exist in the form of thin interbeds, and their lateral thickness varies largely. It is very important to accurately describe the thickness distribution of igneous rocks for well location deployment and reserves evaluation. Based on the known thickness distribution and combination law of igneous rocks in drilled wells, it is considered that overflow igneous rocks in the form of thin interbeds have a great influence on oil field exploration and development. The influencing factors such as combination, total thickness and igneous rock ratio were systematically studied, which lead to different seismic response characteristics of thin interbedded igneous rocks. Based on real data, different analysis models were established to demonstrate the influences of the three factors. It is considered that igneous rock ratio is the main controlling factor affecting the amplitude of seismic response. Relationship between igneous rock ratios and amplitude was established by using actual wavelet forward modeling, and the thickness of thin-interbed igneous rocks was predicted using constrained sparse pulse inversion. The result shows that the predicted thickness is in good agreement with actual drilling thickness, so this method is helpful to quantitatively study the influence of igneous rocks on underlying structures. The research results have good guiding significance for further exploration and reserves evaluation.

Key words: thin interbed, igneous rock, seismic response, thickness prediction, Paleogene, Bohai Sea area