Seismic Sedimentology And Its Application Research In Neogene Jiaowei Formation In Weizhou11-1 Oil Field

Weizhou11-1 oilfield is located in Weixinan depression of Beibu Gulf.The area of structural lithologic trap is 26.66 km~2.It's the anticline-type reservoir controlled by a west east strike fault.Due to the influence of sea level changes and wave action,the Jiaowei formation developed mainlyshoreface and shallow sea face depositional systems.With the deepening of the oil field development,the reservoir geological research scale needs to get smaller to the single layer for reservoir fine description.Weizhou11-1 oilfield isan offshore oilfield.It has a few drilling wells,and the wells are irregularlydistributed.And differentsedimentary microfacieshas different thickness and different lithology of the sand bodies.Soit's difficult to study sedimentary microfacies of inter-well reservoir.It ascertains the sedimentary microfacies development characteristics according to the analysis data from the core and logging data.The paper research the crosswellsedimentary microfacies by combining wells data with seismic data and utilizing the method of seismic sedimentology.On the basis of the chages of regional sea level and sedimentary environment,under the control of different grsdes of depositional cycle,combining wells data with seismic data,this paper build up the equivalent formation framework by using of time-frequence analysis and frequency decomposing technology.Finally the paper divides the minimum isochronous stratigraphic nits into fifth-order sequence which is equivalent to substratum.Under the guidance of principle of seismic sedimentology and using various methods such as the inversion of seismic wave indicating form characteristics,strata slice technology,seismic waveform classification technique,seismic attribute optimization techniques,and frequency division interpretation technique,the seismic faces of the sand group in Jiaowei fifth-order sequenc are fine presented.After the much information feedback,Itreduce the uncertainty of theseismic interpretation.Combining with the geological characteristics of different layers,and under the control of sedimentary mode,the seismic facies are converted tosedimentary facies.In the way,the paper fine studies the offshore sandbar,the mainbody of the shoreface sandbar,the lateral of the shoreface sandbar,shoal sandbody and rip current trench.Finally using the inversion of seismic waveform characteristics,the paper predicts the permeability of the sand body which is present through the technology of seismic sedimentology,And provide geological basis for abnormality of water breakthrough.