Development of rubber barrel for HTHP test packers

Considering the unqualified performance of rubber barrels of test packers for ultra-deep, ultra-high-temperature, high-pressure wells in Northwest and Southwest China, a high-temperature high-pressure (HTHP) rubber barrel was developed for Ø193.7 mm test packers. This invention adopts a triple-rubber structure design, in which the middle rubber works to seal, and the vulcanized steel mesh and tension spring of two end rubbers enhance the pressure-bearing capacity and retraction capacity. Fluorocarbon (FKM) rubber was selected to improve the thermal resistance of the rubber barrel. Through finite element analysis, it is verified that the structure design and hardness of the rubber barrel can meet the design requirements. According to API 11D1, the HTHP sealing performance of the packer was tested in the laboratory. The pressure test results show that the packer rubber barrel is rated for 204 ℃, 105 MPa and V0 grade. The rubber barrel was assembled into the existing testing packer for prototype tests. The lower and upper parts of the packer managed to sustain pressure differences of 105 MPa, and the change rate of the dimensions of the packer was less than 5%, when the tool was heated from 150 ℃ to 204 ℃. The reliability of the packer was further verified via field applications. The successful development of the testing packer promotes the efficient development of ultra-deep, ultra-high-temperature, high-pressure oil and gas fields.