Petroleum Development Oman (PDO) has invited international companies to bid for its contract to provide feed water for generating steam for its thermal-based enhanced oil recovery (EOR) project targeting the Qarn Alam field in north Oman.
The majority state-owned oil and gas producer has floated a tender for the design and construction of a water treatment plant that will treat hyper-saline produced water to boiler feed water specifications for the Qarn Alam EOR scheme.
The project delivery mechanism adopted by PDO for this venture is based on a 20-year contract (with a 5-year extension option) to be awarded on a Design, Build, Own, Operate and Transfer (DBOOT) basis, the company said in a backgrounder on this key initiative.
“PDO is seeking a technology provider who can work with us to treat the produced water to boiler feed water (BFW) quality. This is in line with the PDO water management strategy of reduce, reuse and relocate.
This new project will save aquifer water for future use, as Oman lacks inland fresh water/potable water which is a valuable resource, (as well as near potable water which is also valuable).
It will also minimise deep water disposal and will ensure a regular and reliable supply of steam to support oil production,” it stated.
Steam injection is key to harnessing the hydrocarbon potential of the Qarn Alam field, a highly fractured carbonate based reservoir which is believed to hold a Stock Oil Initially in Place (STOIIP) of an estimated one billion barrels of heavy oil. By heating the reservoir, the viscosity of the heavy oil will be reduced, thereby enabling its flow to the surface.
Plans drawn up by PDO for the further development of the field, which first came on stream in 2011, envisage a major water-based component in the overall operation.
It calls for the large-scale supply of produced water for treatment and eventual conversion into steam before it is injected into the reservoir. Waste water will have to be suitably disposed of as well.
“The Qarn Alam steam project is an integral part of Petroleum Development Oman’s enhanced oil recovery portfolio and is the world’s largest scale development of this nature.
Over the coming years steam injection is expected to rise to over 14,000 tonnes/day, oil production to over 25,000 bbls/d and the thermal process is expected to significantly raise the field’s ultimate recovery,” said PDO.
Around 45,000 cubic metres per day of brackish water is presently pumped from an aquifer located not far from Qarn Alam. It is treated via reverse osmosis (RO) to produce boiler feed quality.
Just under 50 per cent of the brackish water is recovered as boiler feed quality water, with the remainder disposed of via shallow and deep water disposal methods. Hyper saline disposal volumes presently average around 25,000 cubic metres/day through deepwater disposal, according to PDO.
As part of the contract, which is based on a Design, Build, Own, Operate and Transfer (DBOOT) model, the selected bidder will be required to undertake the engineering, procurement and construction of the proposed water treatment facility. It includes the installation of water storage tanks, transfer pumps, and utilities to operate the facility.
“PDO guarantees to provide the contractor with approximately 25,000 cubic metres/day of produced water.
The contractor will be compensated based on its actual recovery of treated water. In-turn the bidders will be required to guarantee a minimum yield of boiler feed water, as part of this tendering process, which would then be part of the subsequent contract,” the national oil company stated.