Research On Sedimentary Characteristics Of Angdachengzi Oil Reservoir In Yudong Area

Under the theory of sedimentology theory、high resolution sequence stratigraphic andseismic sedimentology and adopt an integrated data of core information, well log data、seismic data to establish isochrohal stratigraphic frame of high resolution sequence of thestudy area, to identify the types of sedimentary facies and its characteristics, At last give auseful guidance for the next exploration and development.At first, under the theory of high resolution sequence stratigraphic, by using of thecontrolling of marker bed, sedimentary cycle, thickness and combination of well data andseismic data, To establish isochrohal stratigraphic frame of high resolution sequence in thestudy area; on principle of base-level cycles, On the base of interfacial property, diagnosticthickness, sequence structure, stacking pattern, The Yangdachengzi oil layer can be dividedinto1long period cycle and3medium period cycle, YangⅠ, Yang Ⅱ and YangⅢ respectivelycorresponding to the3medium period cycle. The formation interface of every medium periodcycle is the scour surface of bottom of rivel tunnel, reflecting the evolving process ofcontinuously water depth of becoming deeper and deeper.Subsequent, by the observation of core information and the analysis of individual wellsection of sedimentary facies of core holes, it has shown that the Yangdachengzi oil beddeveloped fluvial facies and delta facies, include river subfacies, embankment subfacies, riverflood subfacies and delta front subfacies, varied types of microfacies: point bar microfacies,riverbed detainment microfacies, natural levee microfacies, splay microfacies, flood plainmicrofacies, subaqueous distributary channel microfacies, subsea interdistributary baymicrofacies and so on. The sedimentary period of Yang Ⅲ, Yang Ⅱand the early sedimentaryperiod of YangⅠ developed meandering river deposition, in the study area, there was a laketransgression at the late sedimentary period of YangⅠ and the sedimentary facies turned intodelta front subfacies deposition.At last, the physical property of Yangdachengzi reservoir has been analysed. The resultshow that The porosity of Yangdachengzi oil layer ranges from2.1%~21.2%with average10.67%, and the permeability ranges from0.01mD to53.2mD with average1.76mD. Thereservoir is medium porosity and low permeability. Then analysised the influence ofsedimentary to reservoir physical property from the detrital composition and detrital texture,research shows that the compaction of detritus make the physical property of reservoir worse,and the denudation of feldspar make the physical property of reservoir better. The hydrodynamic conditions is stong, the sedimentary facies with coarse grain size particledeposition generally develop the better reservoir, the river subfacies developed the bestreservoir in the study area.