The Fluvial-Aeolian-Lacustrine Sedimentary System Analysis In Arid Climate:

It is many kilometers strata in Jiangling Depression Cretaceous, which is affected by the structure, adequate sediment supply and the subtropical arid climate. As the complex geological conditions, the low degree of exploration and drilling, it still has abundant remaining resources, promising exploration strata, which has a large exploration potential and prospects. Some research works and amount of achievement have done on the studies of sedimentary systems in Jiangling Depression Cretaceous, but lack of detailed study. The river-aeolian dunes-lacustrine depositional system study on Jiangling Depression Cretaceous helps to grasp the expansion of the existing resources and tap the potential of the initiative, but also has a wealth of academic research value.In the paper, the research object is Cretaceous of Jiangling Depression, and the research method is the combined considering of continental sequence stratigraphy, sedimentology and seismic sedimentology, and the effect on the deposition of the arid climate. The integrated use of a variety of geological, seismic, well logging, core informations, through combination analysis and prediction, the sequence stratigraphic of Cretaceous established. Then research of spatial distribution of fluvial-aeolian dunes-lacustrine depositional system is done in the framework and the sedimentary model determined.In full digestion and absorption on the previous studies of the Jiangling Depression, comprehensive apply of cores, logs, seismic and analysis of laboratory data, fluvial-aeolian dunes-lacustrine depositional system conducted an analysis. First, based on core observation, lithologic facies and petrographical assemblage has divided. Based on petrographical assemblage, sedimentary structures, and logging data, a comprehensive analysis of a single well sedimentary facies that the Cretaceous fluvial-aeolian dunes-lacustrine depositional system mainly developed six subphase and ten microfacies and its Narrow analyzes. Summed up the logging facies and paleoclimate evidence is analyzed.Combined core, logging data, seismic data and geochemical data, sequence stratigraphy has been analyzed. Mainly based on seismic reflection the termination of seismic reflection, lithologic association, sedimentary facies evolution, logging curve shape, Cretaceous is divided into four sequences:SQh, SQyl, SQy2, SQy3. And five sequence boundaries had identified. The sequence stratigraphic division and correlation of key wells and seismic profiles, the sequence stratigraphic framework has built, and main controlling factors of arid climatic sequence are studied.Based on the analysis of sedimentary facies,combined with the seismic attributes (RMS、Avg inst freq) and strata slice, fluvial-aeolian dunes-lacustrine depositional system research has done in the sequence stratigraphic framework through the methods of point (single well)-line (connecting-well)-surface(plane). The spatial and temporal distribution of depositional systems evolution characteristics is characterized. With the fine characterization of the sand body distribution and internal characteristics, summed up the fluvial-lacustrine depositional system sedimentary model. Then predict the favorable study area of fluvial-aeolian dunes-lacustrine depositional system, channel sandbody with favorable area of oil and gas, the salt lakes gypsum mudstone favorable area of salt.