摘要：At persent, multi expandable patching can’t be operated below the patched period of casing damage wells, a varible diameter expandable cone has been designed, so expandable tools can be put into wells with small diameter and expanded with large diameter which can achieve the purpose of patching for casing damage wells for many times. The indoor prototype testing showed that the tools had a suitable structure, start-up pressure was 3–5MPa,complete closure pressure was 52MPa,maximum overall diameter increased from 188 mm to 220 mm, with the same size of conventional expandable cone, expandable rate was 17.02%.The research results showed that expandable force increases linearly with the increase of thrust, expandable tools could be put into wells with small diameter and expanded with large diameter with the help of variable diameter expandable cone, it should have a broad application prospect after rudcing the closure pressure.
