Research On Sequence And Sedimentary Systems Of Palaeogene Dongying Formation In JZ16-2 Surrouding Area In The North Of Liaodongwan

Based on sequence stratigraphy, seismic stratigraphy, sedimentology and petroleum geology, integrated with 3D seismic data, logging data as well as cores,this paper studied the spatial distribution of sequence and sedimentary systems along with its control factors in JZ16-2 surrounding area in the north of Liaodongwan basin .The Dongying formation here developed three sequences: SQd3, SQd2 and SQd1 upwardly, while the maximum flooding surface can be identified in SQd3 and SQd2 which be further divided into ESTd3, HSTd3, ESTd2 and HSTd2.In SQd3, the synsedimentary faults was well developed near Liaoxi Salient extending northeast to southwest discontinuously. The rising blocks of the synsedimentary faults performed as salients showed two uplifts and three sags overall.The synsedimentary faults in ESTd2 and HSTd2 decreased apparently and fault activities weakened, which was predominately located in the northwest. Simultaneously Liaoxi Salient disappeared and Central Salient combined with its western parts comprised a united uplift. The tectonic activity in SQd1 ceased on the whole, and the northwest part uplifted, resulting as a southeast-dip slope.The fan delta, braided river delta, meandering river delta, lacustrine and sublacustrine fan sedimentary systems developed in Dongying Formation. The lacustrine system dominated earlier stage whereas delta dominated the latter. The distribution of sedimentary system in the tectono-sequence framework present as follow: in SQd3, lake is very vast and fan delta developed under fault break zone in Central Salient and also in the south part of the area. The braided delta in the west was controlled by Paleo-Liaohe river. In ESTd2, Paleo-Linghe river and Paleo-Liaohe river determined the braided river delta, and the lake-floor-fan present in the east from slump. In HSTd2, the lake shrinked and braided river delta as well as meandering river delta appeared. In SQd1 braided river delta and lacustrine developed.The spatial distribution of sedimentary system was dominated by the coupling of provenance system and the slope-break. Paleo-Linghe river and Paleo-Liaohe river were significant to the sedimentary system researched. The fan delta was attributed to steep fault-break zones whereas braided delta to gentle slope-break zones and the relevant valley. The tectonic slope-break zone separated the facies critically.