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Abstract According to the reality of bedded rock salt and clay interlayer for underground oil or gas storage carven in China，considering the existing interface element between salt rock and weak interlayer，the interface element taking nodal displacement and pore pressure as degree of freedom，is used to simulate the initiation，propagation and fluid seepage of weak layers resulted from hydraulic damage. Based on the fluid-solid coupling theory of porous fluid diffusion and deformation，the coupled damage model of dual media for salt rock with formation interlayer is established. This model can depict the crack propagation process and reflect the seepage flow of interface. Then，some numerical simulations are carried out to analyze the seepage and crack propagation characteristics of high pressure fluid on interface between salt rock and clay. The results show that the fluid pressure decreases along the interface element direction and the aperture of the opened fracture is fan-shaped during the leakage process of high-pressure fluid along cavity surrounding rocks. It is concluded that the effects of interface seepage on pressure distribution are very important. For the tightness and stability of the oil and gas repository，the inner pressure of oil or gas repository should be controlled to avoid the oil and gas leakages on the interface for salt rock with interlayer.
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Received: 04 May 2012
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2012, Vol. 31 
