The conditions of high temperature, high pressure and high sulfur content in deep well oil and gas exploitation put forward higher requirements for the sealing ability and service life of the downhole packer. K344 steel belt packer can improve the pressure bearing capacity of the expansion rubber cylinder and the stress condition in the process of pressure bearing and service life through the laminated steel belt between the inner and outer rubber cylinders, which is suitable for the requirements of deep well oil and gas exploitation. In this paper, the finite element software was used to simulate the setting process, the contact stress distribution law of the key components (inner rubber cylinder, outer rubber cylinder and laminated steel strip) and the mechanism of laminated steel strip to prevent the rubber cylinder from "shoulder protruding" were obtained. The optimal distance between the laminated steel strips at both ends and the optimal radius of the hoop fillet were selected through simulation analysis. It provided a reference for the optimization design of steel belt packer in practical production and application.

        A brief description of using ultrasonic was given to test loosened rock circles and the existing problems were discussed such as uphole, suction expansion hole and water leakage hole presented in the water coupling testing through the analysis of the mechanism of probe coupling based on the ultrasonic reflectivity theory. It was compared and analyzed that the method of sealing water injection, coupling methods of cream coupling agent, capsule ultrasonic probe and a new coupling method of three-capsule ultrasonic probe was proposed and it was successfully used in the engineering applications for Pingshuo coal industry limited liability company, China. The result showed that this method was simple, convenient and feasible.