Ayn Dar Oil Field

Ayn Dar Oil Field is an oil field located west of Buqayq City in the Eastern Province of the Kingdom of Saudi Arabia. The drilling rig was first used at Ayn Dar Well No. (One) on April 10, 1948. Significant oil reserves were discovered on July 22, 1948, at a depth of two km in the Arab 'D' zone. A second well was drilled five km south of the first well, and by the end of that year, drilling at Ayn Dar Well No. (Three), located another five km further south, was still ongoing.

Development efforts in Ayn Dar Field expanded with the inauguration of the gas plant in February 1959. Approximately two hundred million ft³ of associated gas were injected to maintain pressure in both Ayn Dar and Shedgum (in the Ghawar Field).

Saudi Aramco continued its expansion efforts and development of facilities, and in 1971, the company aimed to increase its facilities and plants to enhance and boost its energy production, including in Ayn Dar area. As part of this effort, Gas-Oil Separation Plant No. (One) was expanded. The company added two modern separators to separate gas from oil coming from production areas. A significant portion of the separated natural gas was then reinjected into the oil reservoirs to maintain pressure.

There are several methods to enhance and develop production in the oil and gas industry, including seawater injection. However, the interaction of seawater's salt with the subsurface formation can sometimes cause production issues, such as clogging reservoir pores, which affects output. To address this problem, the salt must be removed before injection, a process known as (sulfate removal).

To enhance and develop production at Ayn Dar, Saudi Aramco operated one of the largest sulfate removal facilities in the world. In September 2020, the company began operating five giant units for sulfate removal on the eastern edge of the Ghawar reservoir, which is considered the largest oil and gas reservoir globally. The start of operations followed the contract signing in January 2018, with implementation beginning in October 2018. The construction of the sulfate removal plant at Ayn Dar took twenty-one months.

The sulfate removal units provide over 12,000 ga of water per minute for use in enhanced oil recovery. Each unit of the one hundred thousand m² facility pumps high-pressure Gulf water, transported from Saudi Aramco's seawater treatment plant in Qurayyah, through fine membrane filters for injection into Ayn Dar and Fazran fields in Ghawar.

These units reduce sulfate concentrations in seawater from 4,400 ppm to less than two hundred ppm. The nanofiltration membranes are designed to remove large dissolved salts, including divalent ions and higher, and ions with a charge of two or higher. Although the salts and small dissolved ions are monovalent, they will pass through the filters because they have no effect on the reservoir formation.

According to this process, the produced water from the Ayn Dar facility is sent to the North Ghawar and Lower Fadhili reservoirs. Notably, the Kingdom's territory contains a small number of massive, highly productive oil reservoirs, characterized by low gas flaring rates per barrel and low water production rates. This results in fewer impurities per unit of oil and reduces the energy required for separating, handling, treating, and reinjecting fluids. These factors collectively contribute to reducing the carbon intensity in the sector of exploration and production of Arabian oils.

As part of its ongoing development, Saudi Aramco began using its first drilling rig, designed by the company's engineers and manufactured to its specifications, at Ayn Dar in April 2017. This rig commenced drilling its first well, providing Saudi operators and engineers with an opportunity to test the capabilities of the most advanced drilling rig in the Kingdom and the Gulf Cooperation Council region.

This drilling rig is the most technologically advanced in the Kingdom and the region. With a power of three thousand horsepower, it can drill wells up to thirty thousand ft deep. The rig's mud control systems and cement tank allow the drilling crew to maintain pressure control during drilling. Additionally, the blowout preventer system is certified to withstand pressures of up to 15,000 psi.

Saudi Aramco completed the construction work for the production enhancement projects at Ayn Dar and Fazran, achieving a total production capacity of 175,000 bbl per day.