For an onshore pumping to offshore platforms and injection into a sealine the Reciprocating pumps are applied becuase of high discharge pressure (about 215 bar) and low capacity 22 m3/hr. this case is case is for gas production sealine.
Also in your case it shall be the same type but different...
Really thanks to everty body
Regarding all you said about the Pipesys extension and pipephase method for finding the sphere volume (or accumulated liquid hold-up) I should remember you that it will give us the result of slug volume at normal condition and also pigging condition which is useful...