Investigation of Potential Hydrate Problems in Case of Interrupted MEG Injection in the32b Sealine From Offshore to South Pars Gas Treating Plant Phases 2 and 3 UsingOLGA2000

摘要

Phases 2 and 3 comprise of two 1000 MMSCFD wellheadrnplatforms, two multi-phase (Gas / Condensate / GlycolatedrnWater) 32" pipelines and two onshore gas treating plants.rnGas is not dehydrated offshore. Only glycol (MEG) andrnadditives are injected in the sealines for hydrate formationrnprevention. The length of each pipeline is approximately 109rnkm. OLGA2000 is used to manage the operating conditionsrnand to issue the operating guidelines for the pipeline. Thernhydrate formation curve of the raw gas has been calculatedrnwith PROII. The operating conditions along the sealine (Trnand P) have been extracted from OLGA2000 simulations.rnThe combination of the hydrate formation curve and thernoperating conditions graph yields to estimate the locationrnwhere the risk of hydrate formation starts to appear when nornhydrate inhibitor is injected. The results of the simulationsrnshow that a hydrate formation risk will occur approximatelyrn8 hours after stop of MEG injection.rnIt is found that steady-state MEG injection at a rate of 5rnm3/h is sufficient for complete hydrate protection of thernsealine under winter conditions. The resulting inletrnconcentration is 30-35%.