Abstract: In addressing the challenges faced during technical casing cementing in deep and ultra-deep oil and gas wells in China, including long open-hole sections, multiple pressure systems, high risk of lost circulation, poor annulus cement bonding quality, and difficulty in ensuring wellbore integrity, a multi-component expandable packer-type stage cementer was developed. This stage cementer integrated stage cementing and annular isolation functions. It establishes a multi-component sealing mechanism through primary fluid-injection expansion, secondary permanent sealing by curing, and tertiary hydrocarbon-induced enhancement. It addressed the problems associated with conventional independent connection of stage cementers and packers, such as low operational safety, poor long-term sealing performance of hydraulically expanded packers, susceptibility to premature or failed expansion, and packer element damage leading to sealing loss. By integrating core technologies such as safety logic control, load-limiting support of cementing ports, expansion fluid curing, and high-stretch hydrocarbon-sensitive expandable rubber, this tool achieved effective annular isolation, leakage control of secondary cementing and long-term sealing performance in ultra-deep well. This tool has been field-applied in over 300 wells, covering major oil and gas regions such as Tarim, Junggar, and Sichuan. It has supported the construction of 18 key exploration wells, achieving a maximum second-stage cementing quality qualification rate of 99.2%. This technology significantly improves deep and ultra-deep well cementing quality and wellbore integrity, providing core technical support for the country’s deep oil and gas reserve growth and production increase.