Seismic prediction technology for buried hill fracture reservoirs based on fracture formation mechanism analysis
Due to factors such as large burial depth,high difficulty in seismic imaging,and low data resolution,it is extremely challenging to predict fine,high-angle,and small-scale fractures using wide-azimuth seismic data in the deep metamorphic rock buried hill gas reservoirs of the Archean period.The multiple stages of fracture development and complex and variable strike and dip angles further exacerbate the difficulty of using seismic amplitude to invert fracture information.In response to the above difficulties,this paper starts with an analysis of the formation mechanism of fractures in metamorphic rock matrix,evaluates the feasibility of using seismic data to predict the formation ability of fractures in metamorphic rock,and based on this,utilizes azimuthal anisotropy information for fracture density prediction.Firstly,a geophysical applicable evaluation model for the formation ability of fractures in buried metamorphic rocks is proposed.The model innovatively combines the critical strain energy release rate and brittleness index to evaluate the formation ability of fractures in buried hill of metamorphic rocks.Through petrographic definition,seismic inversion,and statistical classification,quantitative seismic interpretation of fracture formation capability is achieved.Concurrently the HTI(Horizontal Transverse Isotropy)rock physics simulation technology based on the Chapman model is used to develop a fitting relationship between fracture density and azimuthal anisotropy strength of different fracture formation capability of rock facies.Based on this,accurate prediction of fracture density by rock facies is carried out based on the interpretation of fracture formation capability.The above technology has been successfully applied to the structure B of buried hill in Bohai.The research results can provide reference for seismic prediction of fractures in similar metamorphic rock buried hill.
Metamorphic rock buried hillFracture density predictionFormation mechanism of fracturesStatistical classificationChapman modelHTI
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