Saudi Aramco has started testing parts of its Wasit gas programme, raising hopes it can be begin part operations this summer when demand for power in the world's top oil exporter peaks, four industry sources said.

Wasit, north of Jubail on the kingdom's Gulf coast will be one of the largest gas plants not linked to oil wells ever built by Saudi Aramco. It has capacity to process up to 3 billion cubic feed per day of non-associated gas from the offshore fields Hasbah and Arabiyah.

Gas remains a top priority for Saudi Arabia as it tries to burn less crude for power generation and water desalination.

Wasit is one of the new gas plants which will raise the raw gas feed for the master gas system (MGS) to almost 20 billion standard cubic feet per day (Bscfd), Aramco has said.

"They have fed gas to boilers from the master gas system because gas from the fields is not ready yet but they want to bring at least one gas train from the plant and one train from the sulphur recovery unit online before June," one source said.

Construction of the main gas plant is almost complete and is expected to start "very soon", said another source.

"The target is to start at least one train or 20-25 per cent of the capacity up and running," said the source.

"Flare is operating, boilers are operating," said another.

But the plant won't be fully operational before the end of the year or the first quarter of 2016, said the sources.

Sources told Reuters in October last year, Wasit was expected to partially start up in the first quarter of 2015 despite some difficulties linked to construction.

Aramco has said Wasit and another project, Karan, that has been in operation since 2012 will likely boost Saudi Arabian natural gas output by an estimated 40 per cent.

The oil giant is building the gas plants in Wasit, Fadhili and plans another new plant in Abqaiq to implement a strategic plan called the "Peak Seasonal Production" (PSP).

Last year, 9 million barrels of crude oil were saved by implementing the plan, Saudi Aramco said in its weekly magazine the Arabian Sun.  - Reuters