The Research On High-resolution Sequence Stratigraphy And Sedimentary Facies Of The Shahejie Formation Of The Paleogene Of The Qing Dong Depression

Qing dong depression is located in the southern Bohai sea-the combining site ofeastern Jiyang Basin and the Tanlu fault zone. It is bordering to the Zhan hua sag withQingtuozi uplift and Kendong uplift at the northwest, adjacent to the Dongyingdepression at the southwest and next to the Lainan-Weibei uplift at the east. Theexploration area is about1200km2, and600km2belongs to the Shengli Oil Field.This depression is clamped by the Tanlu fault, and divided by a series of strike-slipsecondary fracture, defined as the "Mesozoic-Kainozoic dustpan-shaped stretchingdepression", showed as " three-sags, two-uplifts, two-slopes" on the tectonicframework, spread into northeast-southwest.This thesis is based on existing core drills, well logging data, seismic data, usingsedimentology and high-resolution sequence stratigraphy theory and method,researched systematically about the characteristic of the sequence stratigraphy and thesedimentary facies of the Shahejie formation of the the Paleogene of The Qing dongDepression. Had some achievements to the research:①According to the high-resolution sequence stratigraphic theory and method,based on the existing information, the Shahejie formation of the Qing dong depressioncould be divided into3long-term sequence cycle units(LSC1, LSC2, LSC3) and8middle-term sequence cycle units(MSC1, MSC2, MSC3, MSC4, MSC5, MSC6,MSC7, MSC8).②According to the stratigraphic situation of the target region, choosingmiddle-term sequence cycles and long-term sequence cycles as comparing units,create a high-resolution sequence stratigraphic isochronous-correlation framework which based on the analysis of20individual wells and the correlation of6crosssections.③According to the high-resolution sequence stratigraphic framework andexisting information of rock cores, well logging data, seismic data and previousresults, choosing the long-term cycle and the middle-term cycle as units, thesequence-based-lithofacies and paleogeographic maps of the Shahejie Formation hasbeen mapped. Those maps showed that the major depositional systems of the Qingdong depression are delta system and lake system.④Based on the knowns of the high-resolution sequence stratigraphic frameworkand the details of depositional system of Qing dong depression, sand-body isopachmaps and sand-strata-proportion isogram maps are made, which would help thefurther exploration.