Ensuring LNG Liquefaction Facilitys System Integrity: Pipe Pneumatic Testing as a Build it Tight Attribute

In reservoirs, natural gas is found in three states i. e. - non-associated, where there is no oil contact; gas cap, where it is overlying an oil reserve; and associated gas, which is dissolved in the oil. Composition of the natural gas defines how it will be processed for transport. Whether staying in its gaseous state or being transformed into a liquid, natural gas from the well must undergo separation processes to remove water, acid gases and heavy hydrocarbons from the recovered natural gas. The next step in processing is determined by what type of transport the gas will undergo, and specifications are met according to the transportation system. One such transportation is by liquefying the natural gas, called as Liquefied Natural Gas (LNG). Natural gas is liquefied by lowering the temperature of the hydrocarbon to approximately -260oF. This temperature drop liquefies the natural gas, making transportation possible at atmospheric pressure in the form of LNG. The liquefaction of Natural Gas is carried out in facilities called as LNG trains which has a complex network of pipelines running between different sections inside the train. All these pipelines inside the LNG train should be leak proof to avoid any release of hydrocarbon to atmosphere during normal plan operation. Pressure testing is a method used to perform strength and leak tests of a pipeline involved in hydrocarbon transportation. This article focuses on the importance of pneumatic pressure testing of piping system transporting hydrocarbons (Natural Gas in particular) as a clean and safer method ensuring the system is built tight.