Transportadora Gas del Sur (TGS) gathering system crosses a non-conventional gas field collecting the flow from different producers. The high calorific power characterizes this gas, which condenses within the pipeline. The system has been designed for the full development of the deposit. However, it began operating with flows significantly lower than the design value. This translated into the challenge of guaranteeing the flow assurance at the beginning of the operation, since the low flows generated wide accumulations of liquids inside the pipe, and the consequent risk of big liquid slugs.
This paper shows the method that allowed TGS to go through the initial stage, and operate the system minimizing the volume of the slug catcher, avoiding pigging as a measure to control liquids. The results of the simulations made during the design, as well as its later implementation are shown.
TGS built a pipeline of 115 km (71 miles) and 36 inches of diameter that goes through the main non-conventional gas field in Argentina (and third in the world), known as “Vaca Muerta”. The gas pipeline collects rich gas -without previous treatment- from different producers working constantly with two-phase flow. Although the gas flow rate design is 60 MMSm3/day (2100 MMSCFD), it began to work with flows lower than 5 % of the design value. This translates to very low speeds - less than 0.2 m/s (0.7 ft/s), which added to an irregular topography generate large accumulations of condensate along the pipeline - over 20.000 m3 (125800 bbl).