塔里木盆地志留系—泥盆系层序界面的“四位一体”响应特征及其油气地质意义

“Four-in-One”Response Characteristic in Sequence Boundary Surfaces of Silurian to Devonian in Tarim Basin and Its Significance to Petroleum Geology

以塔里木盆地志留系—泥盆系为研究对象,通过对盆地周缘野外露头剖面详细观测、盆内典型钻井岩心详细描述、测井资料分析、地震剖面解释,详细研究了盆地内志留系—泥盆系沉积演化过程中关键层序界面(主要包括S/O界面——对应于地震剖面上的T07,上、中下志留统之间的层序界面——对应于地震剖面上的T16,上、中泥盆统之间的界面——对应于地震剖面上的T06,石炭系、泥盆系之间的界面——对应于地震剖面上的T75)的"四位一体"响应特征,即层序界面在野外露头剖面、钻井岩心、测井曲线及地震剖面上的特征,结果表明:层序界面在露头剖面、钻井岩心上通常为不整合或冲刷侵蚀面,在测井曲线上表现为突变,在地震剖面上表现为上超、下超或削截。进而详细论述了层序界面形成的油气地质意义,具体表现为:(1)层序界面反映了关键时期盆地性质的转化;(2)层序界面为油气运移的重要通道;(3)层序界面有利于圈闭的形成。该研究成果将为塔里木盆地志留系—泥盆系的进一步油气勘探提供重要的基础地质资料。

Based on detailed observation of outcrops of basin rim and the typical drilling cores in basin,analy-sis of well logs and interpretation of seismic cross-section,the “four-in-one”response characteristic of critical sequence boundary surfaces during the sedimentary evolution of Silurian to Devonian in Tarim Basin are detailedly researched（including S/O sequence boundary surface,corresponding to T07 in seismic cross-section;sequence boundary surface between Upper Silurian and Lower-Middle Silurian,corresponds to T16 in seismic cross-section;sequence boundary surface between Upper Devonian and Middle Devonian,corresponds to T06 in seismic cross-section;sequence boundary surface between Carboniferous and Devonian,corresponds to T75 in seismic cross-section）,in other words,characteristics of sequence boundary surfaces in outcrops,cores,well logs and seismic cross-section.The results show that the sequence boundary surfaces display unconformity in outcrops and cores,saltation in well logs and uplap,downlap or truncation in seismic cross-section.Afterwards, the petroleum geological significance of sequence boundary surface formation is detailedly elaborated as follows：（1 ）the sequence boundary reflects the conversion of the basin nature in critical period;（2 ）the sequence boundary is an important channel for oil and gas migration;（3 ）the sequence boundary surfaces are beneficial to the formation of trap.The acquisition of the thesis research will provide an important foundational geological data for further oil and gas exploration of Silurian to Devonian in Tarim Basin.