High Resolution Processing Of 3D Seismic Data And Characterization Of Fracture Cavity Reservoirs In Tarim Oilfield

Carbonate formation has been regarded as the most important oil and gas producing layer.It takes about 42% oil reserves and 25% of natural gas reserves in the world.In the Tarim basin,the distribution area of carbonate rocks is more than 300,000 square kilometers.And the total of oil and gas resources account for about 40% in all basins.It is the most important exploration stratum in the basin.As important Ordovician carbonate distribution areas with a good development prospects,Tazhong area and Tahe area have always been important oil and gas exploration and development of areas.The Ordovician carbonate reservoir in these areas are featured by large burial depths,its reservoir type is fractured-vuggy with a strongly heterogeneity in vertical and horizontal direction.The reservoir prediction is very difficult due to its low seismic SNR and resolution.Therefore,we need to have a deep understanding of seismic reflection characteristics of the Ordovician carbonate.In this paper,aiming at the fractured-vuggy reservoirs of Ordovician carbonate reservoirs in Tahe area and Tazhong area,we carried out research on new technologies for seismic reservoir prediction and achieved good results in the following three aspects:First of all,we carried out the study of the regional geological background and seismic geological conditions.These researches include the survey of the location and natural environment of the work area,the stratigraphic development and depositional characteristics,the regional tectonic evolution and the main reservoir-cap combination.Secondly,we use a stabilized inverse-Q filter to process the three-dimensional(3D)seismic data in Tahe oilfield and Tazhong oilfield,conducting seismic amplitude compensation and waveform phase correction,simultaneously.Comparing the inverseQ filtered result directly with the raw seismic data in terms of seismic profiling,interior information within the reservoir,characterization of faults and fracture-vuggies.Thirdly,we perform 3D visualization on the raw seismic data and inverse-Q filtered data in the Tahe area and in the Tazhong area.Comparing the corresponding relationship between faults and fracture-vuggies,and estimate the Q value from the 3D data volume to establish the corresponding Three-dimensional attenuation coefficient model.Though the above research,we demonstrate the advantages of stabilized inverse-Q filtering in enhancing seismic resolution,strengthening weak signals,and improving lateral continuity of reflections,and reveal that this method can improve the accuracy of fracture-vuggy characterization in the Ordovician carbonate reservoirs.