Diverless subsea hot tap system

摘要

A diverless process of tapping a pressurized subsea pipeline without removing the pipeline from service. The process includes the steps of lowering and landing a measurement tool onto the pipeline in order to check ovality and straightness of the pipeline with the measurement tool. Pipe lift frames are lowered and landed onto the pipeline spaced from a chosen location. The pipeline is lifted by hydraulic actuators or mechanical screws on the lift frames. A hot tap fitting and accompanying orientation frame are lowered and landed on the pipeline between the pipe lift frames. The pipe lift frames are incrementally raised until the pipeline is fully seated in the hot tap fitting and orientation frame. A fitting clamp is secured to the pipeline. A hot tap machine is lowered onto the hot tap fitting and orientation frame. The pipeline is then tapped with the hot tap machine. The pipeline is thereafter lowered by deflating the lift frame bags.