Fractured reservoir is one of the main oil and gas reservoirs in Gulong-Xujiaweizi area of Daqing oilfield

and Yingcheng Fm is the main deep gas target in this area. The tectonic event that has influenced the tec-tonization of Yingcheng Fm in this area is believed to have occurred after the deposition of the 1 st member of Qingshankou Fm during early Late Cretaceous. The tectonic differential stress value at this stage has been measured by using the quartz dislocation density method

and the tectonic stress field at this stage in the study area has been numerically simulated by using the elastic-plastic incremental method. The simulation shows that the maximum principal stress in the area was in NNE-SSW direction in early Late Cretaceous

and the tectonic stress values was characterized

as a whole

by nearly meridional and zonal distribution. The tectoclase development zones of Yingcheng Fm in Gulong-Xujiaweizi area are predicted to be located in the western part of Gulong area and the western and northern parts of Xujiaweizi area

and they would be the favorable oil and gas accumulation areas.