High Resolution Sequence Stratigraphic Framework And Distribution Of Subtle Trap Of Paleogene In Wei Xinan Depression

The paper build high resolution sequence stratigraphic framework of Paleogene in WeiXinan sag accroding to the theroy of “v-c”,which is based on seismic data, geologicaldata,logging data and drilling core data.Based on the stratigraphic framework andsedimentary facies, this paper analysises the types and distribution of subtle trap,mainly toobtain the results and understandings as follows:Ten third-order sequences，inculded in two second-order sequence,are divided fromLiu Shagang formation and Weizhou formation,which are named SQ1-SQ10form battel totop. SQ5can be devided to three forth-grade sequences.Accroding to the vertical stacking pattern of the ten third-order sequences in LiuShagang formation and Weizhou formation,this paper insist that two layered sequence isbuilt on three layered sequence;two layered sequence, three layered sequence and fourlayered sequence are usually built on two layered sequence or four layered sequence.Stratigraphic overlap trap,Unconformity trap,Lithologic lenticular trap, Lithologicalupdip pinchout trap and Paleochannel sandstone trap are distributied in Paleogene in WeiXinan sag,which are controled by sequence interface and sedimentation.Stratigraphic overlap trap and Unconformity trap are distributied in the firstsecond-order Sequence，which are obviously controled by sequence interface; Lithologiclenticular trap is mainly distributied in the first second-order Sequence，which have thefeature of controlling by sequence interface and sedimentation; Lithological updip pinchouttrap and Paleochannel sandstone trap distributied in both the two second-order Sequence，having the feature of controlling by sedimentation.