Abstract:To cope with the sedimentary multicycle of Ordovician weathering crust in Lower Palaeozoic group and the sedimentary rhythm of Shihezi&Shanxi formations in Upper Palaeozoic group in the Shanganning basin, we use fractal geometry method to analyse the field acoustic impedance log data. Research led to the conclusion:the power spectrum of acoustic impedance increment is inversely proportional to squared frequency, but is directly proportional to the power spectrum of reflection coefficient; and only in a certain scaling area in dual logarithmic coordinate system, can the relation between fitted power spectrum and frequency be expressed as S(f)∞f-β, which coincides with the definition of fractal geometry. In the expression β is the fractal scaling parameter that describes formation structure. Acoustic impedance logging curve in this area is of statistical self-similarity (i. e. fractal property)in a certain scaling interval. The corresponding β contour map involving 20 boreholes is given in the article. We can see from this map that the low β area is coincident with the known hydrocarbon area quite nicely, and that the stretch tendency of favourable hydrocarbon area is shown clearly. The method also brings good effect in analysing the formation structure and hydrocarbon-bearing characteristic of synthetic acoustic impedance sections.
王大兴, 赵玉华, 陶宁. 应用分形标度律研究储层结构及含油气性[J]. 石油地球物理勘探, 1996, 31(6): 815-825.
Wang Daxing, Zhao Yukua, Tao Ning. Analysing both structure and hydrocarbon state of reservoir by using fractal scaling law. OGP, 1996, 31(6): 815-825.