| In this paper, the author selects Nanpu Sag as the research area, the Dongying Formation of Paleogene as the research object, sequence stratigraphy, petroleum geology, sedimentology, and tectono-stratigraphic analysis as the theoretical guidance, sequence stratigraphy study as the main line, and combine with sedimentary filling and main fault activity study. On the basis of fully summarizing and utilzing previous research results, the author take use of detailed and plenty geological, core, logging, and 2D, 3D seismic data, construct sequence stratigraphic framework of the target layer in the research area, extract typical sedimentary system types, analyze and epurate sequence architecture style, and last, summarize the coupling relationship of the sequence of the target layer, sedimentary filling, and tectonic movement in the research area.This paper altogether includes five chapters:In the first chapter, the author mainly introduces the research status of sequence stratigraphy of continental rift basin, and the exploration and research status of Nanpu Sag. The author believe that sequence style is closely related to episodic tectonic movement, and sequence style and its internal sedimentary system structure have obvious response to episodic tectonic movement. There are various opinions on the research of sequence stratigraphy in Nanpu Sag, and no unanimous opinion has been reached. While, as a very important target for oil and gas exploration, the tectono-strtigraphic research of Dongying Formation is of significant meaning. In the end of this chapter, the author show the research thought of the paper.In the second chapter, the author introduces the regional geological characteristics of Nanpu Sag. Nanpu Sag tectonically locates in the North of Huanghua Depression in Bohai Bay Basin, area being 1932km~2. It is on the basement of North China Platform, a complex fault basin controlled by many synsedimentary basement faults, and developed by the Mesozoic, Cenozoic block faulting movement. The Palegene went through from faulted lake basin period to strike-slip faulted lake basin period. The bottom boundary of Sha 1 was taken as the boundary, and its every period can be divided into two episodes. While, the second phase of strike-slip faulted period was in faulted lake period of Dongying Formation(Ed). On the whole, it deposited a suit of fan delta, underwater fan, delta clastic sediments, at lacustrine background. In the late Palegene period, Bohai Bay Faulted Basin uplifted as a whole and suffered denudation; in the Neogene period, the whole depression formed an integrated basin, could be divided into strike-slip depression and accelerated subsidence period, and mainly deposited a suit of fluvial facies sandstone, conglomerate, and mudstone in Guantao Formation, Minghuazhen Formation. Among them, Guantao Formation was mainly braided river sedimentation, while, Minghuazhen Formation was mainly meandering river sedimentation.The third chapter is mainly about the sequence stratigraphic framework analysis in Dongying Formation of Nanpu Sag. On the basis of summarizing previous structural belt patterns and main fault properties, the author combine with the recognition of sequence boundary, single-well stratigraphic sequence analysis, and the sequence framework style of typical profile and the research of main sequence boundary, and indicate that: the filling sedimentation in Dongying Formation of Nanpu Sag can be recognized 5 third-order sequence boundaries: SBEd3x,SBEd3s,SBEd2,SBEd1,SBNg. From the seismic sequence analysis and single-well sequence analysis, the author can see that, Dongying Formation of Nanpu Sag has the characteristics of sequence framework in faulted basin, and belongs to shrinking period of fault depression. But its variation in sequence and depositional system tract are still controlled by main fault activity inside the depression. Among them, the movements of Xi'nanzhuang Fault and Gaoliu Fault have direct control over sequence stratigraphic framework and sequence architecture styles. Following are the characteristics:â‘ It has the sequence architecture characteristics of faulted basin. Each sequence can be divided into three depositional system tracts, such as, LST, EST, HST;â‘¡The sedimentation was mainly controlled by Xi'nanzhuang Fault, Baigezhuang Fault, and Gaoliu Fault, which are on edge of the depression, and also controlled by the movement of No. 1, No. 2, No. 3, and No. 4 Nanpu Fault of the south depression, and their structural high part.â‘¢The differences of the main fault activity resulted in different sequence development in different structural belts. The main fault had control over the thickness center of the sequence development. The fault activity in the period of Member 3 of Dongying Formation was the strongest, and then gradually decreased, and its control over the sequence development gradually decreased too.The emphasis of the fourth chapter is the extraction of typical sedimentary system. Combining with core observation, 3D seismic data interpretation, and drilling lithology logging curve data, by studying core sedimentary facies, single-well sedimentary facies, and extracting typical seismic facies, the author finally sum up 5 types of sedimentary system, developed mainly in the period of Dongying Formation of Nanpu Sag, including: lake delta, fan delta, lake, nearshore subaqueous fan, slumping subaqueous gravity flow, and deep-water turbidity current, and so on. These sedimentary systems have an evolutionary sequence in time evolution, that is, fan delta-nearshore subaqueous fan-delta and its combination, composing an integrated extending and shrinking filling sequence of lake basin.The fifth chapter is mainly dealt with sequence architecture of Nanpu Sag and its response to tectonic activity. The author select 4 typical through-well profiles in the research area, process fine stratigraphic sequence correlation and sedimentary system analysis, and extract two typical sequence stratigraphic styles, developed in the period of Dongying Formation of Nanpu Sag: complex two-level slope break sequence architecture style, fault-terrace belt sequence architecture style.1. The complex two-level slope break sequence architecture styles are mainly situated at the downthrown side Laoyemaio structural belt of the mid-western Xi'nanzhaung Fault and No. 5 Nanpu structural belt. It was affected by the shovel-like fault activity, mainly controlled by basin edge, and resulted in the formation of rollover anticline in fault controlling steep slope belt and the formation of complex two-level slope break on anticline flexure slope break setting.2. The fault-terrace belt sequence architecture styles are mainly situated at the fault crossing of Xi'nanzhuang fault and Baigezhaung fault, and fault-terrace belt formed by Gaoliu fault. The fault-terrace belt is composed by multi-level fault structure and creates a path for multi-level transporting sediments. It often develops two to three faulted slope break belts (synsedimentary faulted terrace) along the steep slope belt of the depression. They control the development of the depositional system tract and the differentiation of the sedimentary facies belt. That is a remarkable character of this kind of sequence model.By analyzing the settling velocity, sequence thickness, and the relationship with main fault activity inside the depression, and the control of synsedimentary fault activity over the development of depositional system tract inside the sequence, the author summarize the sequence developing characteristics, the coupling relationship of sedimentary filling and tectonic movement in the period of Dongying Formation of Nanpu Sag.On the whole, Dongying Formation of Nanpu Sag was at faulted shrinking age. The tectonic movement decreased, but the fault activity variation had obvious control over the development of sequence, and sedimentary filling, such as the affection of Xi'nanzhuang Fault and Gaoliu Fault activity. The sedimentary evolution of Dongying Formation of Nanpu Sag formed into an integrated sedimentary cycle: the lake level rose from early to middle Member 1 of Dongying Formation, and then regressed. During this period, the water had small-scale level and depth variation. Until middle of Member 2 of Dongying Formation, the water area of the lake basin was the widest. Tectonic movement, development characteristics of provenance system, and variation of lake level, with the restriction of those above factors, it created such a unique sedimentation in the period of Dongying Formation of Nanpu Sag.In the period of Member 3 of Dongying Formation, tectonism was comparatively strong, tectonic subsidence was strong; lake level just started to rise but still comparatively low; provenance were abundant. All the above caused the development of sedimentary systems, such as, nearshore subaqueous fan, fan delta, basin fan, and so on. Among them, it mainly developed nearshore subaqueous fan, basin fan, and so on, in LST; it mainly developed fan delta, turbidite fan, and so on, in HST. In the period of Member 2 of Dongying Formation, tectonism decreased, lake level rose; LST was less developed than in the period of Member 3 of Dongying Formation; EST was widely developed. The main sedimentary systems were nearshore subaqueous fan, delta fan, and so on. In the period of Member 1 of Dongying Formation, tectonism was further decreased; lake level started to decline, and became nearer to the provenance. All of them caused the absence of EST, LST and HST developed into large type of delta sedimentary system, till promoted to sub-sag.
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