High steep reflection characterization technology for interior of metamorphic buried hills in Bohai Sea:A case study of Bonan low uplift
The fractured reservoirs in Archaean buried hills within western Bonan low uplift of Bohai Bay Basin generally exhibit high steep seismic reflection characteristics.Due to complex tectonic movements of Indochina Peninsula,Yanshan Mountains,and Himalaya,the reservoirs change very fast laterally,and conventional technical methods are difficult to accurately predict the distribution range of reservoirs,which seriously restricts the deployment of buried hill exploration.To reveal the seismic response mechanism and identify reflection characteristics of fractured reservoirs in buried hills,this study conducts seismic forward simulation to confirm that there is a good correspondence between fractured reservoirs and high steep reflections and then uses the vector decomposition algorithm to improve the signal-to-noise ratio of seismic data.On this basis,edge detection is performed on the filtered seismic data by using the Canny operator to obtain edge bodies that reflect geological targets such as buried hill faults and fractures.Furthermore,the gradient structure tensor algorithm is used to calculate the dip angle of the edge body,and the horizontal strata are filtered out depending on the dip angle to preserve effective geological information.The research results indicate that the joint innovative application of vector decomposition,edge detection,and the gradient structure tensor algorithm can more accurately extract discontinuous reflection information from seismic data,thereby characterizing the favorable zones of fractured reservoirs in buried hills.The research results are effectively applied for the exploration of the Archaean buried hills within western Bonan low uplift,with the BZ26-6 oilfield successfully discovered,achieving a new breakthrough in buried hill exploration in the Bohai Sea area.
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