186 / 2019-06-11 19:08:14

Study on sequence stratigraphy and sedimentary facies of Cretaceous in west slope of Songliao Basin, China

Songliao Basin, Western Slope, Sequence Stratigraphy, Sedimentary Facies

In order to study the characteristics of the fourth-order sequence boundary on the western slope of Songliao Basin and restore its sedimentary environment, the high-frequency sequence stratigraphic framework of Quantou Formation-Nenjiang Formation on the western slope was established by means of well-seismic correlation analysis, palaeogeomorphology restoration and hydrocarbon generation potential analysis, on the basis of fully investigating and researching the predecessors and comprehensively utilizing various data such as core, logging, analysis and seismic data. In the framework, the thickness of the fifth-order sequence stratigraphy is controlled at 10-20m. There are 9 third-order sequences, 16 fourth-order sequences and 54 fifth-order sequences. There are two complete Lake transgression-lake regression cycles from Quantou Formation to Nenjiang Formation, namely Quantou Formation-Qingshankou Formation and Yaojia Formation-Nenjiang Formation. The distribution characteristics of sedimentary systems and sand bodies in the sequence framework are analyzed. At the same time, identification templates for seismic reflection characteristics of sedimentary bodies such as gravity flow channel, sublacustrine fan, scale limestone, estuary bar, sheet sand, distributary channel and distal sand bar are established. From Quantou Formation to Nenjiang Formation, river, lake and delta sedimentary systems are developed on the western slope, and sandy conglomerate, shale and carbonate rocks are deposited. Many types of sedimentary rocks provide various reservoir spaces for oil and gas.