Some wells in ultra-deep fractured tight gas formation are faced with severe sand production problems in west china. It is important to study the mechanical properties of fractured sandstone.

Based on triaxial compression experiments on cores from fractured tight sandstone reservoirs, we investigated the strength and deformation characteristics and the failure mode.

The experimental results show that the strength and elastic modulus of fractured sandstone cores with different fracture angles are lower than those of intact sandstone. Samples with 50° −60°fracture angles have lower peak strength and Young's modulus and tend to fail along the fracture easily. Eventually, four types of failure mode are summarized based on the experimental results. Samples with other fracture angles always have a single-plane shear failure across the nature fracture in triaxial compressive experiments. Fractured samples with the same fracture angle have larger peak strength under a larger confining pressure.

This study presents necessary message for field practices to better understand the mechanical properties of natural fractured sandstone, which is helpful to confirm mechanism for the Kuche reservoirs sand production problems.

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