Saudi Aramco is prequalifying contractors for the second phase of its plan to develop unconventional gas in the north of the kingdom, and has extended the bid deadline for the first phase by another month.

International engineering, procurement and construction (EPC) contractors were invited to prequalify for the second phase in late January and a tender is now expected to be released in March. The names have also been changed from the first and second phase to System A and System B.

The scope of works for System B includes the construction of 50 wellheads as well as 50 flowlines, six inches in diameter. The wellheads and flowlines will be linked to five gathering centres each with a capacity of 50 million cubic feet a day (cf/d).

The gas from System B will then be sent through a 70-kilometre pipeline to Waad al-Shamal, the industrial phosphates city that will be fed with gas from the scheme. Industrial support facilities (ISFs) will also be constructed.   

MEED reported in September 2014 that the scope of works for System A included one gas gathering centre with a capacity of 50 million cf/d as well as a central control centre in Waad al-Shamal.

“There is a lot of work in System B, especially around the gathering centres,” says an oil and gas source based in Saudi Arabia. “This will be one of very few contracts being tendered by Aramco this year.”

System A is being tendered on a lump-sum turnkey basis and is being offered as in-kingdom EPC (IK-EPC) only. This means all the engineering and project management will have to be carried out by personnel based in Saudi Arabia.

Two contractors are vying for System A. They are:

• JGC Corporation (Japan)
• SNC Lavalin (France)

It has yet to be established if System B will also be offered on an IK-EPC basis.  Usually IK-EPC does not attract as much interest from contractors compared with when an open tender is offered.

All the surface facilities for both systems will be skid-mounted, meaning they can be transferred elsewhere when the reservoirs have been depleted.

The gas is held in tight formations and will involve fracturing (fracking) of the rock to release the gas. Both contracts do not include any provision for the sub-surface production activities.

Producing tight gas will still involve water being mixed with sand or chemicals and blasted into wells at high pressure. The rocks are fractured and gas is released.

The most likely area for exploitation is at Turaif, close to the Jordanian border. This means the formations in question could be similar to the Risha tight sandstone wells in Jordan, which are being explored by the UK’s BP.

If the formation is tight sandstone and is similar to Risha, then some experts believe each well could produce 20-30 million cf/d and would be much easier to exploit than shale gas.

The big question that still remains is where the water will be coming from. Any form of exploiting non-conventional gas requires large volumes of water for the fracking process and, therefore, needs water supply wells and water disposal wells. Water handling facilities will also need to be built and all of this could come in a later EPC contract.

The two options would be to either import the water through a pipeline or trucks, or to source it from the region itself. It is not known whether an aquifer has been discovered in close proximity to gas fields. All formations are different, but the initial 50 million cf/d of gas would require 500-1,000 barrels a day (b/d) of water. A road tanker can hold 200 b/d, so trucking water in as a temporary measure is not unfeasible.