Study on the cause classification and prevention methods of casing damage

The casing damage wells in non oil layers are mainly distributed the N2 and SI-SII shale interlayer, types deformation dislocation. main reason is that injected water enters into shale, cementing quality poor, it easy to form an invasion area after invading along channeling channel, which reduces stability of formation. Under effect geostress, force generated by formation sliding weak surface directly applied casing, causing shear damage; reservoir concentrated SII1-5 layers, analyzed as a result high pressure injection large difference plane interlayer pressure; on fault caused slip softening activity excessive pore both sides fault. This paper expounds measures taken daily management from aspect prevention, provides basis for prevention control future.