In Search of Better Water Quality Through Continuous Monitoring

Abstract

The simplest way to measure return on investment for an offshore water treatment system is to determine whether using the system actually reduces the risk of paying a fine for violating water pollution laws. This has typically been done through laboratory tests—required by regulators—on periodically collected samples of treated water. But increasingly, water testing systems are being installed on production platforms offering constant updates of the effectiveness of the water treatment systems. The argument for them is that what flows out of oil fields changes constantly, with surges and slugs dense with hydrocarbons. An unnoticed surge or slug can cause a sharp increase in the oil level in the treated water that is disposed overboard. Without quick adjustments, these excursions can create a telltale sheen around a platform, which can lead to trouble. “There is the dreaded sheen,” said Sandy Rintoul, executive vice president of Wilks Enterprise, which was recently acquired by Spectro. “If there is a sheen on the water, watch out. The helicopters will see you pretty soon.” Wilks sells tabletop devices, used on platforms for periodic processed water quality checks that have been used for decades. It now faces multiple competitors in a niche where new testing methods are for sale. If done properly, those tests can indicate how a platform will fare when tested for regulatory compliance. “They (platform crews) typically use it at least once a day. You see some do it four times a day. If something is going on with the system and there is an issue, they could grab samples every hour,” said Rintoul. A small but growing number of platforms have installed constant monitoring systems. The future of this option will depend on convincing operators that there is a favorable return on investment in monitoring systems that cost many times more than periodic checks. There was keen interest at the annual meeting of the Produced Water Society, which spent one day at its 3-day annual Produced Water Seminar, held 14–16 January in Galveston, Texas, for presentations and debate on the value and effectiveness of continuous monitoring and its future. At the meeting, an employee of a water treatment company asked an engineer from a major oil company what it would take to convince operators of the value of smarter water treatment systems. The answer was: “It is hard to prove how much you can save when you do not know the problem you will solve.” One answer came from MyCelx, a young company that sells equipment for water polishing, which reduces the oil content at the last stage of treatment. Also called tertiary treatment, this step is often taken when there is an upset pushing up oil levels of water from the primary and secondary treatment systems. A case study conducted by MyCelx covered 2 years’ experience on a deepwater facility in the US Gulf of Mexico where the company observed 10 to 12 upsets a year, some lasting for days.