Abstract: Permian cementing was leakprone in the Shunbei Oil & Gas Field, and the loss of annular cement surpassed 2 000 m, which led to severe casing damage in the production period. To solve this problem, a stage cementing collar with packer was developed, performance evaluated in the laboratory, and applied in fields. The tool works well not only with the conventional function of the stage cementing collar, it can also expand the packer upon the first-stage cementing to seal the layers and prevent the leakage of the second-stage cementing and thus improve the integrity of annular cement sheaths. After the expansion, the annular sealing capacity of the tool could reach 20 MPa, and when the circulation holes were closed, the internal sealing capacity should not be lower than the internal pressure strength of the casing. The developed tool was applied in nine wells of the Shunbei Oil & Gas Field. The results revealed that the average leakage of the second-stage cementing was reduced from 105.1 m³ to 3.5 m³, and the missing length of annular cement declined from 2 048 m to 350 m, saving about 11.0 million yuan in cementing. The stage cementing collar with packer could solve the leakage problem in the cementing of the leakprone well sections which tend to leak in long open holes. The lessons learned in this study provide technical support for the efficient development of the Shunbei Oil & Gas Field.