Studies On The Structure Mode Of Baigezhuang Region And The Identification And Prediction Of Structure Fracture Of Reservoirs

For the first time, the special integrated applications of multi-disciplines and new technologies are used to study the structure fracture of Jurassic sandstone of Baigezhuang region in the dissertation. On the basis of abundant fine descriptions of core, the imaging and dip data, the identification informations of fracture with conventional logs, the parameters of seismic attribute, the detected data of fracture with correlative analyses of 3D and the prediction data of the finite element numerical simulation of fracture are inter-testified to qualitatively and quantitatively determine the structure fracture of this area. The regional structure interpretation with 3D seismic data shows that the graben and shied mode faults of the Baigezhuang, which developed a series of normal faults which stroked in NE(NEE) and dipped NW or NW, came into being in the rift development stage of II Act of the Bohai bay rift basin in Mesozoic and Cenozoic and resulted from the protrudent boundary of the basin, i.e. the strike-slip and stretch processes of Baigezhuang fault. It is the regional structure stress field formed in the processes of formation of the major faults of buried hills action on the graben that controlled the development of the fractures of sandstone of Mesozoic of Baigezhuang region.The studies show that the sandstone reservoirs of the buried hills of Jurassic in Baigezhuang region developed three groups of fractures, which most tend towards in NE(NEE). Most of the fractures are tension-shear high angle fractures, 50 percent of which are effected and bear oil. As the major percolation flow channels of sandstone reservoirs of Mesozoic, the macro and micro permeability of fracture are respective 25-50 10-3 m2 and 15.75 10-3 m2 and its porosities are 0.24% and 1.9%. Although the fractures are developed in both sandstones and mudstones, they mainly cut the same formation. Different groups of fractures are vertically connected in ladder shape and form the fracture net, which improve the permeability of the formations and makes the formations good fracture-pore style reservoirs. The integrated identification of fractures with the BPO interpretation of logs and the 3D seismic fracture interpretation technology were used to predict the development and distribution rules of fractures in vertical and plane directions of Mesozoic reservoirs of Baigezhuang region. The plane distribution of the stress fields of different major oil reservoirs determined with finite element numerical simulation provides a theoretical foundation for the research of the plane distribution of the fracture. Thus, the quantitative prediction of the tectonic fractures is possible. The actual prediction of the distribution of fractures with the several technologies mentioned above fits the data of the drilling nicely. On the basis of all kinds of fracture data, the characters of the buried hill reservoirs of Mesozoic are considered as fracture-pore dual mediums, and then the hydrocarbon reservoir was predicted.