Tectonic Evolution Of The East Of Beach Area In Liaohe Oilfield And Its Effection To Petroleum And Hydrocarbon Accumulation

The eastern beach area of Liaohe is Cenozoic extensional rift basin, Extension and strike-slip is the form of tectonic deformation in Cenozoic. tectonic activity controlled the generation, migration and aggregation of oil and gas. Exploration proved that the understanding of structure law plays a key role in improving the understanding of the reservoir forming law of the eastern beach area of Liaohe , searching for new oil and gas rich block, deepening the exploration and improving economic efficiency. After understanding the regional tectonic features and evolution, the paper applied the principles of structural analysis, the theory and methods of modern structural geology and basin analysis to carry out the analysis of tectonic geometry and kinematics based on detailed interpretation of seismic data. And Establish tectonic evolution history profiles, analyze regional structural deformation and explore its genetic mechanism. The paper combined with deposition and reservoir forming to study on controlling of tectonic evolution to hydrocarbon accumulation in study area based on the results of the tectonic features and evolution research.The paper applied comprehensive study method of qualitative analysis of 3-D seismic data, timing of sequence stratigraphic framework and quantitative analysis of the ancient thickness to establish structure- stratigraphic framework of Cenozoic based on sequence stratigraphic framework, classify reasonably structure units and analyze evolution process in various periods in study area. And considered it’s double-fault continental depression controlled commonly by Gaizhoutan fault and Yannan fault in Cenozoic in study area. Fault area is the most basic structural elements in the study, Fault activity is the main formation of development of depression. The study area developed different scale,diffrernt occurrence and different property faults, NS-trending and NE- trending faults composed of the basic fault system of the basin. Basement faults and cover faults interlaced on the vertical and horizontal direction, Overlay vertically and comprised two coordinated and unified structural system, namely the extensional structural system and the strike-slip structural system. Extensional structural system controlled the sedimentary, and play a decisive role in the distribution and development of the Paleogene sedimentary .Strike-slip structural system inherited and transformed the early extensional structural system, the present structural pattern is the result of superposition of multi-period structural deformation. The tectonic evolution in Cenozoic can be divided into four distinct stages, namely extensional rifting period, thermal subsidence period after the first rifting, another rifting and strike-slip extension and thermal subsidence period after the first rifting, Completing a complete cycle of rifting approximately. Multi-period structural movement caused difference in basin structure in various rifting periods, thus resulted in disparity in tectonic deformation and sedimentary formation, several transgression to retrotransgression sedimentary cycles,several source-reservoir-cap assemblages, development different types of oil and gas reservoirs in different structural locations and the characteristics of E-W zonation.