古火山活动的地震地质解释

Palaeovolcanicity interpretation using seismic and geological data

目前，我国已有多个以火成岩为储层的油气田相继发现，进一步开拓了找油领域。火山活动与大地构造及盆地发有密切相关，尤其在拉张性裂谷盆地的发育过程中，无不伴随火山活动。火山活动又势必在地层中留下它们的遗迹和产物，这些产物往往具有比砂、泥岩大的波阻抗，从而以强反射及具一定形态特征展现在地震剖面上，成为独特的火成岩地震相。由于火成岩具有不同的构造形态、产状特征、分布规律，因此，在地震剖面上出现各种各样的反射异常现象。文中列举了席状火山岩特征、凹陷区复合火山岩特征、隆起区复合火山岩特征、V形反射异常，以及它们的地质解释。

Several hydrocarbon fields whose reservoir is volcanic rock have been discov ered in China,showing a new hydrocarbon exploration realm. Volcanic activity wasclosely related to geotectonics and basin evolution. Particularly, volcanic activitymust happen in the evolution of tensile rift basin. Volcanic activity must producevolcanic sequence that has higher wave impedance than sand and mud stones, sothat volcanic sequence is characterized by strong reflections and special shape inseismic section, forming a particular seismic facies of volcanic rock. The volcanicrocks cause various anomalous seismic reflections in seismic section because of theirstructural shapes,occurrence and distributions. Described in the paper are V-shapedreflection anomaly and seismic reflection patterns of sheeted volcanic rock as well ascomplex volcanic rocks in depression and uplift. Their geological interpretations arealso recommended briefly.