High-resolution Sequence Stratigraphy And Sedimentary Facies Research Into Qingshankou Formanction Of Heidimiao Srea

Heidimiao area is located in the middle of the Changling sag,which is in the south of Songliao basin. The type of reservoir widly spreading in this area is lithology, fault - lithologic.But the previous sedimenrary model can not satisfacte the practical application.The study takes aim at the Gaotaizi reservoir sediment, and takes petroleum geology, reservoir geology and sequence stratigraphy as the theoretical guidance.Comprehensive utilization of geology, geochemistry, geophysics, laboratory data analysis, the high resolution sequence stratigraphic framewor in Heidimiao area has been established, which helps to certify the regional tectonic evolution of the deposition. The new sedimentary model in this study area could provide guidance for further exploration and development.Based on principles of high-resolution sequence stratigraphy, combined with core and logging data sequence boundary feature recognition, the Qingsankou Formation is divided into a long-term base level cycle, two long-term base level cycle and a number of medium-term base level cycle. On this basis, a stratigraphic framework of the whole region has been establishedBased on the geological background research, combined with mudstone color value, heavy minerals, lithology analysis shows the source of these depositions in this area is Tongyu - Baokang River in the sourth of Songliao basin, witch enters the study area in the form of two branches.The deepth of the water was deepenning during the period of 1th Qingshank Formation formed, while it was shallowing form 2th Qingshankou Formation, leading the shoreline continually retreat to north and east.In the context of transgression during the 1th Qingshankou Formeiion depositing, a transgressive delta has formed, and the delta front facies deposit in study area. In the medi- south of this area, the sand of underwater distributary channel and river mouth bar constitute the skeleton of sand deposition; in the medi- north, those sand bar are frontier development and offshore bar and relatively isolated Under the strong wave effect, a large amount of underwater distributary channel sand has been transformed into inverse rhythm sand bar, with the river mouth bar formed a contiguous distribution deposition.During 2th Qingshankou Formation, the shore line flinchs to north-east, and delta plain facies has appeared, while the core drills the meandering river fun delta superimposed sedimentary in Hei55 well. The sedimentary system formed is different from the delta formed during 1th Qinghsankou Formation. The differentiation of the source result the delta deposits differentiation and the front bar is not as developmental as the sand deposit during 1th Qingshankou.During the period of 3th Qingshankou Formation, the withdrawal of water makes the plain facies widly spread in study area, and shallow the depth of water. At the same time, with the reduce of the capacity for debris, and the intercepts to the wave of the bar makes the dimendions of the river mouth bar smaller than the previous deposition.