OIL SHALE FRACTURING EFFECT OF SHOCK WAVES GENERATED BY PLASMA-IGNITED ENERGETIC MATERIALS EXPLOSION

摘要

Shock wave tests on oil shale samples were carried out in water medium by using the composite electro-thermal chemical explosion method through the shock wave generator, and strain measurement system was also introduced, and the cracking effect of energetic materials and copper wire to oil shale was analyzed. In the process, 1# oil shale sample was tested with energetic rods containing different mass of energetic materials, while 2# oil shale sample was tested with 0.3 mm copper wire explosion. The results show that the 0.3mm copper wire explosion has a small cracking effect, while the energetic rods have a much stronger cracking effect on the oil shale, and the impact pressure and the process impulse of the energetic mixture deflagration which produced strong shock wave are positively related to its mass. It also suggested that the strain time curve during the cracking process is the comprehensive effect of the strong shock wave produced by the copper wire and the energetic materials' explosion. What's more, the impact wave effect is mainly emerging the splitting failure, and a small amount of shear failure is mainly concentrated in the interlayer. Moreover, under the impact of shock waves, the physical properties of oil and gas reservoirs are changed, and its permeability is obviously enhanced which is helpful for the analysis and diffusion of oil and gas. The reduction of the mechanical strength parameters proves that the shock wave plays a definite certain damage to the physical structure of the reservoir. Experiments results show that shock wave technology can be used as pre-fracturing technology in in-situ development of oil shale.