The Study Of Distribution Rule Of Structural Fractures On Taizhao Low-permeability Sandstone Reservoir In Daqing Oilfield

From core description, outcrops observation, thin-section and specimens analysis, reservoir behavior research, numerical simulation of tectonic stress field and structural fracture,based on the analysis of the tectonic evolution and tectonic stress field the distribution characteristics,development rules and effects of fractures on exploitation were comprehensively evaluated in Putaohua low-permeability reservoir, Taizhao area.By the tectonic stress field of nearly EW-orientiation compression in the late Yanshannian period, there developed 2 sets of EW,SN tension fractures and NW,NE shearing fractures with high angles. The development degree of fractures is controlled by lithology, thickness, fault and tectonic stress,etc.From the true breaking rule by the experiment of high-temperature/high –pressure rock mechanics and the result of core description,on the basis of numerical simulation of paleotectonic stress field the distribution rule of fractures is predicted on the level. By the effect of modern stress field, EW fractures are the main seepage, where their connectedness, opening and permeability are best. they need be considered seriously for pattern arrangement in the early of oilfield development. It can get the better effect that rectangle and rhombus well patterns are placed along the EW orientiation of the main seepage. Natural fractures and current tectonic stress field control the distribution of the artificial fractures and affect injecting pressure and effect of injecting water.