The Application of Full Azimuth 3-D Seismic Fracture Detection Technology in the Prediction of Favorable Reservoirs within the Shengbei 5 Well Area Tight Sandstone Region
Xiang, Guo; Jianbin, Ran; Xiaowei, Yu; Jinxue, Zhang; Zhengtao, Hu; Yuan, Zhang; Fulei, Li
The study area is located in the eastern part of the Shengbei fault zone where two shallow hydrocarbon reservoirs have been discovered. However, the average depth of lower and middle Jurassic in yanshan is greater than 4000 m. The main reservoir lithology is composed of fine sandstone with an average porosity of 4-6%, average permeability of less than 0.05mD, water saturation of 70%, and has a daily production of 1500-4500 cubic meters.In this paper, fracture development zones are predicted qualitatively and semi-quantitatively by using anisotropy detection technology and wide azimuth seismic data that were newly acquired in 2011. To improve the accuracy of fracture prediction, the analysis of stress field and strain strength is also carried out based on the full azimuth stack seismic data.
The fracture detection technology of wide azimuth 3-D seismic is based on the amplitude information of different offset and azimuth, therefore, it is required that the original data acquisition have high folds based on the high S/N ratio. The data also needs to have a uniform distribution of offsets and azimuths. The folds of the Shengbei 5 well area are relatively higher than the other area, and the distribution of offsets and folds are uniform, the horizontal-to-vertical proportion approaches 1.
Based on the full range of three-dimensional seismic data of the azimuth processing, the density, direction and distribution regularity of reservoir fractures have been predicted using anisotropy detection technology and strain field analysis in Shengbei 5 well area. Through the optimization of methods and parameters, the fracture directions are predicted using the impedance attributes of pre-stack data, the fracture density as predicted by using the frequency attenuation attributes of pre-stack data.The application results indicate that the development of fractures in the West-1 reservoir are primarily E-W-trending. And the development of fracture zones are primarily located on the two limbs of the southern and northern structures adjacent the faults. In contrast, fractures are poorly developed in the axis of structure. The research results provide reference for well proposals and show that the anisotropy detection technology has a promising application prospect based on 3-D full azimuth seismic data.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013