Characteristics Of The Slope Break Belt And Its Control On Sedimentation In Paleogene Of Western Liaohe Offshore Area

Under the instruction of sequence stratigraphy, sedimentology and petroleum geology, this paper mainly does the research on the characteristics of the slope break belt and its control on the sedimentation in paleogene of western liaohe offshore area through analyzing the data of 3D seismic, core and logging.On the basis of the former researchers'achievements, through seismic interpretation and logging analysis, the paper identifies different sequence boundaries in the research area, makes a conclusion of the boundaries and finally establishes the sequence stratigraphic classification scheme. Four second-order sequences (SSQ1-SSQ4) and eleven third-order sequences (Sq1-Sq11) were identified, among which SSQ1 amounts to sha4 formation, SSQ2 amounts to sha3 formation (concluding Sq2-Sq3), SSQ3 amounts to sha1,sha2 formation (concluding Sq2-Sq3), SSQ4 amounts to dongying formation (concluding Sq6-Sq11). By adopting the approach of well tie comparison and log-seismic data combination, the paper establishes the comprehensive chrono-stratigraphic framework, analyzes the sequence filling pattern and evolution discipline, holds that the sequence development patterns having the obvious characteristics of zonal distribution.Through analyzing the well-tie cross sections, seismic profiles and the sequence stratigraphic isopach maps, two different genetic types of slope break belts are identified, that is faulted slope break belt (syndepositional faulted slope break belt) and flexured slop break belt. Combined with the characteristics of tectonic movements in the research area, the paper clarifies the genetic mechanism and distribution characteristics of the slope break belt, pointing out that faulted slope break belts mainly develop in hainan fault and the sudden change position from slope to sag in the northern part of western slope.After identifying and classifying the slope break belts, the paper analyzes those controls on the sequence development patterns and sedimentation, the paper holds that under the control of the faulted slope break belts, LST are mainly base-basin filling systems, TST mainly contains fan delta and shallow lake sedimentation systems, HST contains fan delta and alluvial fan systems. Under the control of the flexured slop break belts, LST mainly contains the sedimentation systems of shallow lake, normal delta and river, TST mainly contains the sedimentation systems of braided river delta and shallow lake. HST mainly contains meandering river delta, sand bank and delta plain. They both obviously control the distribution of sand body.