Research On Method Of High Accuracy 3D Seismic Exploration At Central Depressions In The South Of Songliao Basin

Central depressions in the south of Songliao basin is the first structural element,main targets of exploration includes Gaotaizi oil reservoir of Qn1, Qn2 and Qn3formation,and includes Fuyu oil reservoir of Q4 formation also. Depth of oil reservoiris about 1600-2500 meter. Fault zone grow in exploration sedimentary facies,distanceof fault extend is short , vertical fault throw is small,and sand body is thin. The typeof oil reservoir mainly includes low relief structure , oil reservoir of fault -lithologand lithological deposit.3D Seismic Exploration of higher accuracy has been operated in Jilin oilfiledsince 2000,and the geologist acquired a lot of new understanding about geologyfrom Exploration achievement. Not only a series of low relief structure and smallfault traps have been proved, but also a series of lithological trap has beenrecognized.But some problem is presence in Exploration yet.this paper establishes aseries of improved seismic exploration methods of high accuracy in the area by theoryresearch and test aimed at problem in Exploration. In respect of seismic acquistion, 3D layout design was analyzed with regard toposition of demonstration,select of observed azimuth,vertical resolution,size ofbin,coverage,max offset, and the type of geometry design.This paper presents thesuitable method of 3D layout design and example. Explosion factors was studiedsystematically, including analysis of explosion energy, explosion pattern,frequencycharacteristic of dynamite source and ghost reflection. This presents methoddetermined shot depth from surface layer structure survey and lithologies. The testsdemonstrated that the combination of multiples shot holes with small charges givesthe best results.The geophone of 30 Hz natural frequency is the most suitable in thearea by analysis and test of geophone type.In respect of seismic data processing, this paper presents three step to solvestatics, which presents kinds of approach to broaden the frequency bandwidth toimproved resolution basing on surface consistent deconvolutio,and summarizes kindsof practical approach to suppress noise by noise characteristic.Prestack time migrationis better approach in seismic imaging in the area and this paper presents the steps torealize , approach of selecting parameter .In respect of seismic data interpretation, this paper mainly studied fine structureinterpretation, reservoir prediction and composite appraisal. This paper presents aseries of approach about calibration of formations, tracing formations interpretation,fault interpretation by coherent body and other way.In respect of reservoirprediction ,a little of technique of seismic microfacies recognition was studied andrelationship of geologic model and seismic section was analyzed by theory model .