Features, Origin and Petroleum Explorative Significance of Crushed Fracture in Clastic Rock

Key words: 
• crushed fracture in clastic rock /
• coarse-sand rock and conglomerate /
• deep petroleum exploration

Abstract: Crushed fracture in clastic rock is created under great press from the gravity of over layer or giant stress by sides, as the contact point of the grain bear big intensity of pressure than others. As the crushed fracture are distributed only within the grain, it can be distinguished from the fracture created by tectonic stress. By studying the crushed fracture in clastic rock of the oil & gas-bearing basin in the western China, it can be seen that the development degree of the crushed fracture has close relation to grain size, type of detrital minerals and the amount of interstitial material. The crushed fracture is easier developed in the coarse-sand rock and conglomerate, and the grains that developed crushed fracture are mostly rigid or come from tuff and lava. Under the same grain size and type of detrital minerals, the development degree of crushed fracture has close relation with the scale of interstitial material in rock. As the fracture can be created in the press of the gravity of overburden rock, and the fracture provide space for oil and gas, it will enlarge the field of petroleum exploration, at the same time, it have great significance in improving oil recovery.