Typical QIKOU SAG Sand Body Geophysical Prediction Method

In view of the present geophysical reservoir prediction of the main problems, weestablish the typical complex geologic model which background to the sedimentaryenvironment of in Qikou Sag and basis on the sequence stratigraphic framework, carry outa variety of research methods commonly used experimental seismic reservoir with forwardmodeling and inversion as a means of combining, clear complex geophysical reservoirprediction method selection criteria in QIKOU SAG, provide technical support for reservoirprediction of the overall QIKOU SAG exploration, and we summed suitable lithologicreservoir exploration reservoir forecasting process base on logs environmental correction,petrophysical parameter calculation, geological modeling method study and the research ofapplicability of seismic reservoir prediction method of forward modeling data.Through hard working five conclusions were generated:Base on the isochronous sequence stratigraphic framework and structural interpretation,analysis speed of a single well as the foundation, consider the time, space, source couplingbetween three factors on the distribution of sand, with Coast slopes’ and Qibeislopes’structural layer as framework, established model libraries, to research QIKOU SAGtypical geological seismic response characteristics. Seismic attributes are widely used in thereservoir sand prediction, the study on applicability of forward modeling data show that: Forthin interbedded sandstone and mudstone deposit in beach bar environments, can bepredicted by the amplitude attributes and in forecast gravity flow sand bodies thickness, thewaveform attributes can be used, if only prediction of sand body distribution range, theinstantaneous amplitude and RMS attributes are better.Currently, model-based well constrained inversion was used widely, when the scope ofthe study included the transition region and not well exist, error of inversion results will belarger, so the impact of model is very large, and the influence of wavelet on the thin andthick sand are not the main factor, in the face of thin layer inversion, need to updatethe concept, focus on the initial model.It is effective that use Spectral decomposition method to predict the gravity flow sandbody, especially for sand which the thickness between5and15meters.and spectraldecomposition can also recover thick sand, but a "pseudo" sand appear. Althoughthe spectral decomposition method for the prediction thin sand is batter, when predict thicksand the result should be judged with ecological and seismic inversion results, so as toreduce the multi solution problem.