A vessel located at the end of a pipeline used to entrap and separate slugs of gas entrained with flowing liquid. It is used at the end of risers from oil and gas reservoirs in which slugs of gas rise with the crude oil as well as water and sand. The slugs of gas or surges are separated in the slug catcher, which has a sufficient capacity to cope with the largest slugs that can be expected. The separated gas and liquid are then able to be processed at a controlled rate.