Burial History Of Volcanic-Sedimentary Strata In SK-2 Well Of Cretaceous Continental Drilling In Songliao Basin

SK? Well of the Continental Scientific Drilling in the Songliao Basin is located at the Song Station nose-like structure of the Xujiaweizi depression,north of the Songliao Basin.The strata encountered from the bottom to the top are the basement of the Paleozoic,Lower Cretaceous Shahezi Formation?K₁sh?,the Yingcheng Formation?K₁y?,the Denglouku Formation?K₁d?,and the Upper Cretaceous Quantou Formation?K₂q?,the Qingshankou Formation?K₂qn?,the Yaojia Formation?K₂y?,the Nenjiang Formation?K₂n?,the Sifangtai Formation?K₂s?,the Mingshui Formation?K₂m?,and the Quaternary?Q?.We restores burial history of the SK? Well by its current situation of stratigraphic stratification,which is significant to basin evolution and oil-gas exploration.The core section of SK? Well is taken from basement to the Denglouku Formation,while the strata above the Denglouku Formation are based on the cutting logging data.The lithology proportions of the different strata encountered in the SK? are divided into detailed sections for the formation compaction correction obtain the debris particle skeleton thickness of each strata through the observation,description and stratification of the core,and the production,observation and identification of the several slices.For the volcanics,we obtain the valcanics hole-deep corelationship applicable to the SK? by taking the pressure hole permeability test which is subjected to the uncompacted volcanics in the Changbai Mountain area and the Yingcheng Formation volcanics.Through the core data,it is clearly that there are two main unconformity interfaces in the SK?,which are the top surface of the Nenjiang Formation and the Yingcheng Formation.Using the interval transit time log data combined with previous research results,the denudation thickness was determined to be 851 m and 654.45 m.The bottom boundary age of the Shahezi Formation was determined to be 118.6 Ma by LA-ICP-MS U-Pb,and the burial history of SK? was finally determined by the principle of backstripping.According to the recovery of burial history and characteristics of sedimentation rate,SK? underwent long-term and rapid depositon and burial during the Shahezi Formation-Yingcheng Formation period,with sedimentation rates of 460.35 m/Ma and186.22 m/Ma.Strata uplifted and denuded at the end of Yingcheng Formation with denudation thickness of 654.45 m.The sedimentary rate was 120.62 m/Ma and 101.77m/Ma during the period of Denglouku Formation of Low Cretaceous and Quantou Formation of Upper Cretaceous.During the period of Qingshankou Formation-Yaojia Formation of Upper Cretaceous,the sedimentary burial rate decreased slightly,but the overall sedimentary rate was still relatively fast,which are 52.24 m/Ma and 72.94 m/Ma.Rapid depositon and burial occurred in Nenjiang Formation of Upper Cretaceous,with a depositon rate of 216.25 m/Ma.The strata returned to rapid uplift and denudation at the end of Nenjiang Formation,resulting in a huge amount of denudation with a denudation thickness of 851 m.During the Upper Cretaceous Sifangtai Formation-Quaternary period,the strata were deposited and buried slowly as a whole,and the sedimentation rate and burial rate were obviously reduced.