| Petroleum and natural gas are the significant goods and materials of humansociety, and the progress and development of human society all rely on them. With thedemand for oil and gas resources increasing every day and under the condition thatthe oil and gas resources are continually reducing, the exploration of complicatedcarbonate oil and gas pool is drawing more and more attention, and its reservoirprediction is still the hotspot and challenge of current research and the importantobject of oil-gas exploration.The study area lies in a region of central Sichuan. The study area is in semi-deeplake facies of the deposition of Da’anzhai Lake Basin. The main production layers arethe thin limestone reservoirs of Dayi Section and Dasan Section. This thesis studiesand analyzes response characteristics of thin interbedded reservoir, based on theestablishment and demonstration of various geologic models to conducts variousseismic inversion methods and analysis, as well as implementing high-precisionseismic inversion of target stratum and reservoir tracking work. The research hasmainly achieved the following results:(1) Based on the wells including Xichong1, Ren4and Penglai7,13geologicmodels of thin and interbedded reservoir are build, and through forward modeling ofthe response features of seismic, it is believed that amplitude is in direct proportionwith reservoir thickness, and when there are thin and interbedded reservoir under it,the amplitude involves complex rules: in case of the spacing of interbed <3m,reflection amplitude will have coherence emphasis; when the gap>3m, the coherencewill recede. Comprehensively the degree of amplitude change and the downwardthin-layer’s thickness express a linear relationship. But it cannot accurately judgechange features of thin interbed by the changes of amplitude, therefore, it cannotaccurately examine and identify reservoir features by regular seismic reflectionparameter.(2) Regarding DCZ009and DCZ071two-dimensional seismic lines in a region ofcentral Sichuan as the test target, choose logging constraint inversion based on model,inversion based on frequency spectral decomposition, stochastic inversion based on density function and so on, which aimed at tuffs thin interbedded reservoir inDa’anzhai. The outcome of these experiments confirmed that the resolution oflongitudinal and profile got with the first two inversion methods are relatively low,and cannot predict the thin alternating reservoir in Da’anzhai effectively. However, thelast method is based on stochastic inversion of density function, and inversion sectiongained from this possesses the feature of high longitudinal resolution and continuousreservoir lateral variation, which has an effective recognition on the thin reservoirstratum with a3~5meters thickness of single layer.(3) Utilizing the random inversion method based on the density function to carryout high resolution speed inversion over10seismic lines in the industrial region andcarry out thin and interbedded reservoir development model comparative analysisover the first great section and the third great section on the inversion surface,obtaining the reservoir development model of the thin limestone of the Da’anzhaisection, the middle and low speed abnormal of the high speed limestone distributionarea may be the fissure development area, namely the main producing area of oil gas.(4) The velocity distribution plan of limestone reservoir is obtained throughtracking the reservoir. And the storage distribution feature of thin interbeddedreservoir within the work area is revealed, which strongly supports the overallreservoir study of study area.This thesis adopted the preferred inversion method to apply to this study area forthe first time and got good geological application effect, which was kind of innovationand has certain guiding significance for the practical production. |
PDF Full Text Request