L51510 Field Observations of Two-Phase Flow in the Matagorda Offshore Pipeline System

Offshore gas production typically involves the simultaneous flow of oil and/or condensate. The oil may he entrained in the gas rising in the vertical well from the sea-bed or may flow under its own pressure gradient; condensate may result from the reduction of pressure from well conditions to pipeline transport pressure and from cooling sea temperatures. It would be unduly expensive to build a gas-liquid separation facility on a production platform, followed by two separate pipeline transport systems for the two phases. It is therefore desirable to examine pipeline systems that carry hydrocarbon liquid and gas together.

Two-phase flow of oil and gas under steady-state operation of the Matagorda Offshore Pipeline System was observed by nuclear densitometry at two onshore sites. Oil flowed into the pipeline system at an average rate of 1.6 Bbl/ MMSCF over the two-month data acquisition period; gas flow was constant at about 200 MMSCF per day.