应用地震信息鉴别花状构造及相似构造样式

DISTINGUISHING FLOWER STRUCTURE FROM OTHER STRUCTURES BY SEISMIC INFORMATIONS

本文应用地震信息研究了如何鉴别花状构造及相似构造样式。提出拆离型及伴生构造与透入型构造的本质差别。认为：透入型的花状构造是以扭应力为主形成的；正拆离型的背冲和扇状褶皱断裂构造是以区域性挤压为主形成的；负拆离型马尾状构造是在区域拉张翘倾运动中形成的。花状构造主断裂在地震剖面上总的特点是上缓、向下合并、陡立地插入基底，向上分叉、向外撒开。研究正花状构造及相似构造样式的形成、分布，对为油气田的勘探、开发提供科学依据起一定作用。

Flower structure is a structural style which is dominantly caused by torsional stress. In seismic sections, positive flower structure is characterized by a reverse fault system, radiating from a centre like a blossoming flower; and negative flower structure generated due to tensionally torsional stress looking like an anticline-shaped structure system with graben faults.In a seismic section, the faults in a flower structure radiate upward and converge downward to cut steeply into the basement. Broom-like structure was generated in an areal tension-tilting tectonic movement. Its faults also radiate upward in a seismic section; but these faults,which show steep upper parts and gentle low parts, form a plough-like fault system nearly tocut into the basement gently. Other geological structures caused due to gravity,such as gravity sliding, plastic formation arching, differential sedimentary compaction, bedrock uplift,formation slumping and antithetic fault structures, are very different from negative flower structure because they are anticline-like systems with graben faults in shallow formations.The negative flower structure is characterized by the major wide faults of slumped anticlinelike structure cutting symmetrically into the basement; and the major fault of graben-anticlinal structure caused due to bedrock arching cutting gently into the basement. Overthrust anticline and fan fold structures were caused by dominant regional compressive force. They are similar to positive flower structure in shallow formations because of their overthrusting character; however,in deep formations,they are different from it because their faults cut the basement with very gentle slope while it cuts steeply the basement. Oil exploration for many year shows that seismic informations are very effective in identifying various geological structures. After a clear ascertainment of structure types, we can determine oil trap types and their distribution, offering reliable geological results for oil exploration and development.