Subsea pig launcher

摘要

A multiple pig subsea pig launcher is disclosed. The pig launcher can be assembled on a production pipeline subsea with the aid of an ROV. In the preferred embodiment, the pigs are connected to each other and spaced apart by a spine. The pig launcher is configured to capture the next pig to be launched in such a manner that the spine behind it is in alignment with a shearing valve; for example, coiled tubing or wireline. Sequential valve operation shears the spine and applies pressure behind the pig to launch it from the launcher past the pig detector and onto a platform for recapture.