Chelates help to boost production for oil and gas customers

Scale is caused by the buildup of metal compounds found in hard water, which negatively impacts the performance of boilers, washing machines, and other equipment. Claw-like organic molecular structures called chelates can tightly “grip” these metal ions, allowing scale to be prevented or removed. Chelates are widely used in cleaning applications, such as laundry and personal care, and are now set to expand their applications into the oil and gas industry.

But, due to constant exposure to water and ground elements, scale builds up in the injection systems. As scale builds up, more pressure is required to push the water through the system. “This is a real problem,” Auribel says. “With increasing pressure, less and less water can be injected without fracturing the rock and damaging the production wells, increasing operating costs and reducing efficiency of oil extraction.”

Traditionally, oil companies have used hydrochloric acid to remove the scale. However, this is a hazardous chemical which must be removed from the well before injection can resume, causing additional costs and lost time. Two companies approached Nouryon with a challenge: find a way to remove the scale build-up in a safer, faster, and more efficient way.

These two companies, Colombia’s state-owned oil company, Ecopetrol, and US-based Occidental Petroleum Co, also known as Oxy, jointly operate the La Cira-Infantas Field located 250 km north of Bogotá, the capital of Colombia.

Nouryon's proposed solution was to use our StimWell chelates. Based on natural and sustainable raw materials, these effectively clean the injection systems and can be left downhole once spent as they are non-toxic and readily biodegradable.

“Acids are not only problematic from an environmental perspective; they can also damage the clay in reservoirs, causing it to weaken, break off, and cause more clogging in injection systems,” Auribel explains. “StimWell doesn’t cause any such damage. Without the need for expensive and time-consuming flow-back to remove acids, operations can resume immediately after cleaning is complete.”

Tests by Ecopetrol and Oxy have confirmed that StimWell chelates provide a safe and effective way to remove scale buildup in water injection systems. The first pilot using StimWell resulted in a 52% increase in the “injectivity index”, a measure of the efficiency of the injection system, while two additional field tests showed increases up to 100%. “Now that we have strong proof of concept, Oxy is preparing to use StimWell to clean more wells,” Auribel says.

“This technology offers performance and environmental benefits to a wide range of industrial applications that involve the use of water, especially important in sensitive areas,” Auribel says. “Furthermore, the global scale of our operations ensures that it can be delivered easily to any part of the world.”