The Tight Sand Reservoir Fracture Prediction and Modeling in Xinchang Gas Field
The Triassic sandstone gas reservoir is a tight sandstone fractured reservoir in Xinchang gas field. The average porosity of reservoir is about 4%. The permeability of the matrix is almost zero. The permeability of gas field is mainly fracture permeability. There are 6 wells in this zone. Two of them are drilled in good fractured zone and with high gas production. So the fracture prediction is very important to this kind of reservoir. Based on pre-stack and post-stack seismic data, we made seismic impedance inversion and analyzed on seismic anisotropy, edge-detection, coherency, dip, azimuth and curvature attributes. Finally it is found that curvature attribute, especially gaussian curvature attribute is closely related to fracture development. We calculated high quality curvature attributes. We use these geometry attributes to detect the large scale fracture (fault, sub-fault and small fault). We use FMI data and seismic curvature to predicted the fracture density of small network fracture. The area which is close to the big fracture, high small fracture density and high porosity is good drill target. We proposed 3 wells, all these wells have obtained with daily output over 20 million cubic meters.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009