Testing biocides in hydraulic fracturing

The process of ‘fracking’ involves drilling a wellbore deep underground, often with a horizontal stage used when a rock bed is particularly shallow. The rock is then fractured using explosives that create small fissures in the rock which aid the flow of oil and gas out of the bed into the wellbore. It is the low porosity of the rock that necessitates the hydraulic fracturing to make a well economical. Without hydraulic fracturing, the well would not produce enough oil and gas to make it worthwhile to drill.

Water, sand and some chemicals are injected down the well under pressure to ensure these fissures stay open under the immense pressure caused by the rock formations above the target rock bed. It is the sand that holds the fissures open which are often just a few millimetres wide. A large amount of water (many millions of gallons) is used in a single frack and the water may come from many different sources, e.g, freshwater, saltwater or recycled water from a previous fracking process.

Most of the chemicals added are those typically used in other industrial processes that utilise water and are added to maintain the integrity of the wellbore, e.g. surfactants, corrosion inhibitors, pH controllers and friction reducers.

Biocides are added to the water to prevent the build-up of bacteria in the water that may lead to acid corrosion or the creation of sulphide-based compounds. Bacterial growth can impair the production of oil and gas wells and can be introduced into the fracking fluid from various sources – including the source water and the proppant. Proppant is the term used for the sand (or other compounds) that hold the fissures open.

Testing Solution

To optimise your processes and ensure efficient usage of biocides, monitoring of chemical content in water is required. With Kemio™ Disinfection, you can generate biocide results in 60 seconds, giving clear results for the operator of over or under dosing.

The latest multiparameter platform from Palintest, the Kemio™ Disinfection tests for free chlorine, total chlorine, chlorine dioxide, chlorite and peracetic acid (PAA).

To find out more about how Kemio™ Disinfection can help you, click here. 

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