Produced water

From Wikimarcellus

Produced water is naturally occurring water found in the sedimentary shale beds traversed by the wellbore. It is generally very saline in nature and presents an environmental challenge for Marcellus shale drillers. Produced water requires proper treatment before disposal. It should not be confused with recovered drilling fluid pumped down a well when it is hydro-fractured.

There is a point where the water that flows up a well shifts from being primarily recovered drilling fluid to that of being produced water. The dividing line can be difficult to discern, yet can be distinguished by comparing the different chemical signatures of the recovered drilling fluid to that of the naturally-occurring shale formation water.

Produced water has very high salinity and total dissolved solids (TDS).

There are also dissolved hydrocarbons present in produced water.