Abstract：
The tectonic movement during the deposition of the Es
3
Formation in the Liuzan Area, Nanpu Sag, is complex, and
the multi-episode tectonic-sedimentary evolution led to great spatial-temporal differences in sequence stratigraphic framework
and sedimentary filling patterns. The research into regional sequences cannot meet the needs of fine characterization of sedimen
tation and sand bodies in the study area. Here we addressed these issues by conducting research focusing on the main oil-bearing
formations of middle-upper part of the Es
3
Formation by using division-correlation technology of continental sequence
stratigraphy. The results reveal the sequence architecture and sedimentary filling characteristics of parasequence sets within the
third-order sequence, and clarify its guidance for oil and gas exploration and development. The first to third submembers of
the Es
3
Formation can be divided into two third-order sequences SQ1 and SQ2. The III and II oil-bearing formations are two
progradational subsequence sets of the lacustrine regression system tract in SQ1 during the tectonically quiet period. With the
gradual shallowing of the sedimentary water body, the study area presents the sedimentary evolution characteristics from "small
plain and big front in a fan delta" to balanced development of “plain and front”. The I and 0 oil-bearing formations are two
retrogradational parasequence sets of the lacustrine transgressive system tract in SQ2 during the tectonically active period. With
an increase of the ratio of accommodation space to sediment supply, the study area presents the sedimentary evolution charac
teristics from the balanced development of “plain and front in a fan delta” to shallow and semi-deep lake facies with the gradual
retrogradation of the fan delta. Laterally, the different activity characteristics of boundary faults control the lateral changes of
the sedimentary environment in the same sedimentary period. The sedimentary characteristics of parasequence sets control the
development of favorable reservoir-cap assemblages in the study area. The middle-late stage of the lacustrine regression system
tract (the III and II oil-bearing formations) and the early stage of the lacustrine transgressive system tract (the I oil-bearing
formation) during the tectonically quiet period are favorable for the deposition of thick reservoir rocks, associated with lacustrine
transgressive mudstone (the 0 oil-bearing formation) deposited at the end of the tectonically active period. These form a favor
able reservoir-cap combination. The architecture characteristics of parasequence sets control the distribution of parasequences
and their internal sand bodies and fluids. The sand bodies in the lower part of the retrogradational parasequence sets are more
developed, showing the characteristics of lower oil and upper water. The top of the parasequence unit is the distribution location
of favorable reservoir sandbodies and hydrocarbon. Through this study, we reveal the sequence architecture and sedimentary
filling modes of the 0~III oil-bearing formations in the middle-upper part of the Es
3
Formation, which provides guidance for the
prediction of sand body distribution and the exploration and development of lithologic reservoirs.
Key words：sequence architecture; sedimentary filling; evolution model; Liuzan Area
Corresponding Authors： sunpk@cup.edu.cn
Cite this article：SUN Panke, JIA Langbo, ZHU Hongzhang, ZHANG Lin, HE Taihong, XU Zhaohui, LI Cong. Sequence architecture and sedimentary filling characteristics of the middle-upper part of the Es3 Formation in the Liuzan Area, Nanpu Depression. Petroleum Science Bulletin, 2021, 01: 16-30.
