High-resolution Sequence Stratigraphy And Depositional System Research Of Es₁ Hongxing Area

The study area is located in the northeast of Jiazhangsi sag, which is a sub-first structural unit of Huangjindai structural zone, East Depression of the Liaohe basin. It's difficult to correlate strata and predict reservoir because of complex crossed faulting and frequent volcanic activities. The topic selection of this paper is based on the need of reservoir exploration and the important role played by sequence stratigraphy in the prediction of lithological reservoir distribution, and the first member of Shahejie formation (Esi) is the main studying target intervalOn the theoretical basis of classical sequence stratigraphy (Van Wagoner et al, 1990) and it's new progression, the petrogeological data in Hongxing area are analyzed in this paper, the methods of predicting subtle reservoirs in sequence stratigraphic frameworks are probed.By studying sequence stratigraphy systematically, the high resolution sequence stratigraphic framework of Es1 in Hongxing area is established. By applying the basic viewpoint of sequence stratigraphy, considering the feature of Eogene faulted-basin in Hongxing area thoroughly, identifying the different scale unconformities of sequence boundary and the equivalent interface by comprehensive applying core, logging, high-resolution seismic and being acted as the key to make isochronous stratigraphic framework, the identification maker of sequence boundary are summarized in Hongxing area, and the correlation framework of isochronous sequence stratigraphy in which the fourth-order sequence acts as the unit is established in the whole sag. Es1 is divided into one second-order sequences, 3 third-order sequences and 15 fourth-order sequencesIt is apparent that source rocks lie in the northeast of study area, through regional geology data analysis, heavy minerals analysis and drawing isopach map of main sandstones. On the basis of establishing the isochronous stratigraphic framework, the main sedimentary microfacies such as sub sea distributary channel, river mouth bar, interdistributary bay, front sand sheet and coastal-shallow, volcanic deposit are analyzed precisely, the sedimentary model and time-space of sedimentary system are studied, the depositional model of the main reservoir sand bodies is representThrough seismic profile and well data analysis, the growth faults are identified and their distribution plan is constructed. Based on the structural framework and the main syndepositional faults system, combined the sequence stratigraphy and structural stratigraphy, we discuss the syndepositional fault's control to the depositional system. The controlling model is put forward, in which the sequence development is controlled by syndepositional faults and associated volcanic activitiesBy applying new theoretical results made by sequence stratigraphy in continental faulted-basins and new techniques in subtle reservoir exploration .