(1. Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. School of Water and Environment，Zhengzhou University，Zhengzhou，Henan 450001，China；3. Faculty of Earth Resources，China University of Geosciences，Wuhan，Hubei 430074，China)
Abstract：The length of casing well completion structures that composed of casing，concrete ring and surrounding rocks are much larger than their outer diameters，so the problem of dynamic response of casing well completion structures caused by incident plane SH wave can be simplified as 2D plane problems. The casing，concrete ring and surrounding rocks are all considered as homogeneous isotropic elastic bodies. The wave function expansion method and conformal mapping method of complex function are adopted. The theoretical solutions about the complex coefficients of the scattering and refracting SH waves are obtained based on the boundary conditions that the inner side of the casing is free and the casing，concrete ring and surrounding rocks are tied completely. The casing well structures of 102 well in a gas field is taken as an example. The dynamic stresses of the casing caused by earthquake SH waves are calculated. The maximum stress is larger than the yield stress. Therefore the earthquake is the direct reason that causes the casing deformation in this gas field. In the end，the dynamic stress concentration factor is introduced，and the influences of surrounding rocks and concrete ring on the dynamic stress concentration factor are analyzed. Some important conclusions are obtained，which include：(1) reduction the strength of the concrete ring would reduce its dynamic stress concentration factor；(2) the stiffer the surrounding rocks are，the lower the dynamic stress concentration factor in concrete ring would be；(3) dynamic stress concentration factor of surrounding rocks is less influenced by the thickness of surrounding rocks and modulus of concrete ring.
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2012, Vol. 31 
