Cost-Effective Produced Water Treatment

Each year, oil and gas producers in the U.S. spend an average of $1 to $6 billion dollars on the disposal of produced water. For every barrel of oil, five to nine barrels of water are produced. For each MCF of natural gas produced from the ground or ocean floor, the result is 0.1 to 1 barrel of produced oily water. Cost efficiencies in oil and gas production depend on the economics of the produced water treatment and disposal.

When these barrels of oily water are produced, the oil and gas producers must find ways to treat and dispose of the water, which is expensive. In onshore operations, the produced water must be hauled to re-injection sites or disposed of in evaporation pits. Third-party haul away or disposal costs about $0.5 to $8 per barrel of water, depending on the location of disposal from the production sites. This amount can be more than $5 million each year to dispose of 5,000 barrels per day of produced water.

Discharge into evaporation ponds require no visible oil sheen or less than 10 parts per million (ppm) oil content in the water. Some reinjection disposal methods also require less than 10 ppm oil content.

This highly-regulated process is  an environmental challenge because of the trucking footprint, the toxicity of the oils and hydrocarbons and the potential damaging impact to underground water aquifers and surface wildlife. The underground reservoirs can plug or foul, which increases the pressure and reduces the ability to dispose of the produced water.

Currently, Kinetic Hydrate In-hibitors (KHI) are used widely in the production line. They can cause the emulsification of oils and hydrocarbons in the produced water and can compromise existing secondary treatment options, such as float cells or nut shell filters. How do oil and gas producers reduce the oil sheen and dissolve volatile and semi-volatile hydrocarbons in the produced water?

A clean water technology offers a complete break from obsolete filtration, operating on the principle of chemical cohesion. This technique is a clean break from other existing produced water treatment technologies, which are mostly based on mechanical separation, chemical injection or adsorbent technology. This chemical cohesion principle enables the treatment system to remove free, emulsified and dissolved oils and hydrocarbons in the water. It achieves 0 to10 ppm on total oil content including free and emulsified oils. Using this system increases the water quality and makes it amenable for surface discharge, reinjection or reuse, and it removes toxicity and hydrocarbons.