FRACTURE PREDICTION FOR LACUSTRINE CARBONATE RESERVOIR OF THE LOWER PART OF THE 1ST MEMBER OF SHAHEJIE FORMATION ON QIBEI SLOPE,QIKOU SAG

The lacustrine carbonate reservoir in the lower part of the 1st member of Palaeogene Shahejie Formation(Es1x)has been the important oil-gas exploration target in the Dagang oilfield recently.Facts show that the fracture plays an important role in the development and improvement of the reservoir.So it is necessary to effectively predict the fracture system.In this regard,we selected the lacustrine carbonate reservoir of Es1 xin the Qibei area as the main study target for fracture prediction in this paper.Firstly,the geological characteristics of the fractures of the Es1 xreservoir were analyzed;and then,the distribution of macroscopic fracture development zones were predicted by using multiple fractures prediction technologies based on post-stack seismic data,such as curvature attribute analysis and Landmark structure cube analysis;After that,the extending direction and the density of fractures of the Es1 xreservoir were quantitatively predicted by the fractures predicting technologies based on the anisotropy of pre-stack seismic data in the study area;Finally,through the mutual supplement and verification of pre-stack and post-stack results,the fracture system of the Es1 xreservoir is concluded as follows:the fractures of the Es1 xreservoir dominated by structure fracture,are mainly developed around the north slope of NDG fault;The direction of fracture is nearly extended in east-west direction;The fracture developing zones were discontinuous and distributed block-like or belt-like.The prediction results are matched well with the drilling results and useful for further exploration of oilgas of same type in the study area.