Abstract: Drilling plug operations must be carried out after casing repair by means of the traditional expandable casing patching technology,which results in an extended workover period and increased operating expenses.Therefore, non-drilling plug expandable casing patching technology were developed after determination of performance indicators and applying working condition of tools by structural design of non-drilling plug device,parameter optimization of tools,verification of laboratory experiment.Laboratory test results showed that the performance indicators of this device in wells with damaged casing met site implementation requirements.Construction parameters and working conditions were made clear.Moreover,the site implementation flow for non-drilling plug expandable casing patching technology was established.The field test results in Well CDX-56P of Bohai Gulf indicated that this non-drilling plug device could satisfy the site construction requirements for anti-torsion and anti-pressure,etc and it also possessed good field practicability.The successful test of non-drilling plug expandable casing patching technology provided the technical means of shorter operating cycle and lower costs for harnessing the development of wells with damaged casing.