... of fractures increases gradually, and when the displacement increases until the propagation speed reaches 6.67m/s, the fracture mainly propagates through gravels. Reservoir Characterization Upstream Oil & Gas FBG strain sensor test result structural geology pressure-time curve specimen...

...<a<I.0R 10 I t I I Time sec 0 1 2 3 4 G A a >1 .o R 1c i , t i ) Time aec 0 1 2 3 4 Pressure MPa slightly increases as the original flaw size lengthens. It is interesting to note that the K value gradually increases and finally reach- es the critical value somewhere between the points I and F on the pressure-time curves, although the pressure...