| The study of microfacies and sequence stratigraphy is important base of exploration of lithologic and stratigraphic reservoir. In this paper, adopting electrofacies analysis technology and wavelet transform with comprehensive utilization of logging data & geologic information to interpret lithology and microfacies, analyse sequence stratigraphy and set up isochronic formation framework. First of all, interpret lithology and microfacies with electrofacies analysis. In detail, make full use of lots of logging data and take methods of principal component analysis, cluster analysis and bayes analysis etc. so as to set up regional interpretation model, with which lithology and microfacies profiles of wells can be reformed automatically. With the study of regional sequence stratigraphy in Wu-xia district of Junggar basin, we can divide Permian-Jurassic formation into 23 three-order sequences, 7 second-order sequences and 2 first-order sequences so that we can set up regional isochronic formation framework. Then we make research on the geologic meaning of continuous wavelet transform of logging signal, summarize character of time-frequence energy plot of ideal sequence stratigraphic model, advance the divided approach to high frequence sequences based on continuous wavelet transform with logging data and make the division of TSQ2 in M11 and FN1 wells, which is proved to be identical with geologic result. And besides above, we also found that Milankovitch period influences climate so as to control base level change and deposition supply etc., which is a main factor of high frequence sequences development such as fouth-order and fifth-order sequences. At last, dealing with actual data of Wu-xia district in Junggar basin, which proves the methods above are effective. |
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