Interpretação sísmica e análise de atributos - área dolevantamento sísmico 3D de siririzinho (BaciaSergipe-Alagoas, NE do Brasil)

摘要

The main objective of the present thesis was the seismic interpretation and seismic attributeanalysis of the 3D seismic data from the Siririzinho high, located in the Sergipe Sub-basin(southern portion of Sergipe-Alagoas Basin). This study has enabled a better understandingof the stratigraphy and structure that the Siririzinho high experienced during itsdevelopment. In a first analysis, we used two types of filters: the dip-steered median filter,was used to remove random noise and increase the lateral continuity of reflections, andfault-enhancement filter was applied to enhance the reflection discontinuities. After thisfiltering step similarity and curvature attributes were applied in order to identify andenhance the distribution of faults and fractures. The use of attributes and filtering greatlycontributed to the identification and enhancement of continuity of faults. Besides theapplication of typical attributes (similarity and curvature) neural network and fingerprinttechniques were also used, which generate meta-attributes, also aiming to highlight thefaults; however, the results were not satisfactory. In a subsequent step, well log and seismicdata analysis were performed, which allowed the understanding of the distribution andarrangement of sequences that occur in the Siririzinho high, as well as an understanding ofhow these units are affected by main structures in the region. The Siririzinho high comprisesan elongated structure elongated in the NS direction, capped by four seismo-sequences(informally named, from bottom to top, the sequences I to IV, plus the top of the basement).It was possible to recognize the main NS-oriented faults, which especially affect thesequences I and II, and faults oriented NE-SW, that reach the younger sequences, III and IV.Finally, with the interpretation of seismic horizons corresponding to each of thesesequences, it was possible to define a better understanding of geometry, deposition andstructural relations in the area.