莺歌海盆地泥底辟活动期次分析

Periodicities of diapiric rise in the Yinggehai basin

莺歌海盆地是中国近海最重要的天然气探区之一 ,具有超高温及异常高压的独特地质条件 ,中央坳陷形成了众多巨型泥底辟构造。根据对地震资料的高分辨率层序地层学解释 ,精细研究泥底辟构造分布区的地层结构 ,分析泥底辟活动期次。分析结果表明 ,莺歌海盆地的泥底辟构造发育具有不同期、不同步及纵向叠置等特点 ,泥底辟活动具有多源、多幕的特征 ,而多期幕式活动直接导致了油气的多期幕式充注。图 5参 10 (黄春菊摘 )

The Yinggehai basin is characterized by high thermal gradients and overpressure. The diapir structure zone contains rich resources of oil and gas. However, so far the periodicity of diapiric rise in Yinggehai basin has not been cleared. The purpose of this paper is to make clear this problem and find the evidences. Through using the high resolution sequence stratigraphic interpretation and pre stack depth migration of seismic section, and analyzing fluid container parameters, the distribution of source rock and the basic periodicity of diapiric rise were determined. After precisely interpreting reflection termination and studying the forming procession of the diapir structure, it is found that the diapiric rises are characterized by multi source and multi episode, and the diapir structures by different periodicity, different step and vertical stacking. The multi source rock and the special structural thermal system of super high temperature and overpressure in Yinggehai basin made the diapir being characterized by fluid flowing. Through analyzing the result of the diapiric rise and the pooling mechanism, it clearly shows there had certain relation between the diapiric rise and the petroleum accumulation, the multi episodic rise of diapir led to the multi episodic injection of petroleum.