Sedimentary System Study Of Lower Es₂ In Shahejie Formation Of Shanghe Area In Huimin Sag

Many researches have been discussed of the sedimentology and the sequence stratigraphy of the shahejie formation of the Paleocene in Huimin sag, but there was no systemtic reseach on the sedimentary microface to the lower Es₂ in Shanghe area, especially the control factor of the provenance, the depositional sequence and the system tract of the lower Es₂ reservoir in Shanghe area was widely concered. With the gradually impvoving of the exploitation degree , and the gradually increase of the exploratory development difficulty, the problem of the sedimentary microface distribute rule and the origin oritention have been the puzzle of the exploration activity for the long period.The provenance of the shanghe sandstone and the crosswise and the vertical distribution rule of the sedimental microface was systematically analyzed, combined with petrology, stratigraphy, tectonic geology, sedimentology, sequence stratigraphy, geophysics and geochemistry etc.The high resolution sequence framework has been built up of Paleocene in Huimin sag. Four of the second grade sequences has been distinguished, Kongdian group sequence, Es₄ sequence, Es₃ - lower of Es₂ sequence, upper Es2-Dongying group sequence. And four of the third grade sequence has been distinguished to Es₃ - lower of Es₂ sequence, SQ1,SQ2,SQ3,SQ4. The lower of Es₂ belong to the descending cycle of SQ4, can be dividing into three medium-cycle MSC1, MSC2 and MSC3.The paper researched the tectonic mechanics of the sedimental systems, inquired the control factor of the depositional sequence and the sedimentary system, The multi-level tectonic accommodation zone control on the stretch of the sedimentary facies and the direction of the acient river system. The west of the Shanghe area is delta front, but the southeast area mainly develop semi-deep lake and shore shallow lake, underwater distributary channel on the top of the fault stairs; mouth bar in center; distal bar, sheet sand and interdistributary on southeast.Based on the theory of the "Structure control basin, Basin control facies, Facies control reservoir", the paper combine the sedimentary, the tectonic and the stratinomy, find the beneficial facies tract on the basis of strcuctural accommodation belt principle, through the devidition and comparison of sedimentary microface and sequence. The exploratory problem was analyzed by structural dynamics. It is very important to exploration activity on theory and reality.