Sustained　casing　pressure　(SCP)　was　an　urgent　problem　to　be　solved　during　shale　gas　exploration　and　development.　To　cope　with　the　issue　of　SCP,　a　method　of　establishing　gas　channeling　barrier　was　proposed,　and　the　location　of　the　barrier　was　optimized,　considering　engineering　and　geological　factors.　A　series　of　tests,　containing　uniaxial/triaxial　compression　tests　and　cyclic　loading-unloading　tests,　were　carried　out　to　evaluate　the　accumulated　plastic　strain.　Also,　a　full-scale　cement　sheath　sealing　integrity　evaluation　device　was　employed　to　verify　the　appearance　of　the　micro-annulus.　Computed　tomography　scan　and　nuclear　magnetic　resonance　tests　were　performed　to　measure　and　analyze　the　distribution　of　microcracks　and　pores　in　the　cement　sheath　after　cyclic　loading-unloadings.　Numerical　models　of　the　wellbore　assembly　were　established,　which　considered　wellbore　structures　of　different　intervals　of　an　actual　deep　shale　gas　well.　Research　findings　indicated　that　after　loading　and　unloading　a　certain　number　of　times,　the　accumulation　of　plastic　strain　showed　an　increasing　trend　with　the　increase　of　the　measured　depth　in　the　vertical　section,　but　decreased　with　the　rise　of　the　measured　depth　in　the　horizontal　section.　The　method　of　setting　gas　channeling　barrier　was　proposed　and　could　be　used　to　avoid　SCP　by　using　the　cement　slurry　with　low　elastic　modulus,　which　could　significantly　reduce　the　cost　of　cementing　operation.　Many　factors,　including　the　non-uniform　in-situ　stress,　wellbore　structure,　fracturing　stage　number,　casing　internal　pressure,　and　formation　mechanical　properties　were　considered　to　establish　the　optimization　method　of　barrier　locations,　and　this　method　was　verified　by　using　the　logging　data　of　an　actual　well　as　well　as　the　engineering　and　geological　data.