Hydrocarbon Detection Technology Research Based On Quadratic Form Time Frequency Distribution Theory

As the oil and gas exploration level deepens, the oil and gas explorationdifficulties are increasing. Owing to the complicated conditions of exploration, theSNR and resolution of data are very low, thereby seriously impact on effect ofprocessing and interpretation. On the condition that weak signal, there is particularlyimportant to propose a new method of signal detection for the new explorationobject. As a mathematical tool describe random signal HOS theory has been initialapplied in the exploration area; based on this theory, a method were discussed by thisarticle with the view of mending frequency-divided technique and improving thetime-frequency resolution.Frequency-divided technique deriving from B P Amoco is a resolutiontechnique to transforms seismic data to frequency domain or time-frequency domainthrough mathematical transform, through it, cut frequency axis into slices, make useof slices to predicate reservoirs finally. At present sorts of document considered,existing frequency-divided technique include: The information from various sources,the existing businesses of technology are mainly: Fourier transformation, linearfrequency analysis, the frequency distribution.etc. This paper in order to mendfrequency-divided technique and improve the time-frequency resolution, make useof the high time-frequency resolution specialty of quadratic, first propose thefrequency-divided technique based on the quadratic and apply it on the oil and gasdetection, achieved following results:1, in order to solve the problem of cross-term interference in quadratic throughfuzzy fields’ kernel wave-filtering method for restraining cross-term interference andderivating formula of Wigner high-order spectrum fuzzy functions.2, based on fully studying cone-shaped kernel and exponential kernel.Numerical simulations indicated that the cone-shaped kernel function has theadvantages of above two kernels, and has a strong inhibition to cross-terminterference in delay axis and beyond axis.3, by way of moving coordinate to superpose the center point between fuzzy functions signal terms and cone-shaped kernel. Thereby solve a problem that thecone-shaped kernel couldn’t be capable of restraining cross-term interferencebecause of filtering in fuzzy fields directly.4, in order to solve the problem of3D data volume are too massive. So thefrequency-divided technique procedure is improved, avoiding generating Wignerbispectrum diagonal slice3D data volume.In accordance with research base from home and abroad as well as this fieldknowledge of myself，two kinds of methods were discussed by this article need to beintensive studied from following two areas:1, in the thin bed,it can be seen from Wigner bispectrum diagonal slice fuzzyfunctions that space between effective signal and cross-term is close,This goesagainst resolving the thin bed. The formula of Wigner bispectrum diagonal slicefuzzy functions, and increases the space between effective signal and cross-term,improving ability of resolving the thin bed.2, while effectively restraining cross-term, fuzzy field’s wave-filtering methodreduces the time-frequency resolution. So may make us of rearrangement theory oradaptive optimal-kernel and so on to restrain cross-term, and further improvetime-frequency aggregation.