ABSTRACT
Oil and gas deposits are generally colocated with water, which is coproduced with oil and gas during production. Produced water does not have a market as do oil and gas, so it is considered a waste. The cost of its disposal is very low compared to the potential cost of treating the produced water for reuse. The initial character of produced water will include those elements dissolved by the water during the centuries that it lay buried in the unique geologic setting. It will also include any chemicals added during oil and gas exploration and production operations plus any nascent bacteria in the original geologic setting. Also affecting the character of the produced water are any bones, plant residues, shells, and other materials that were deposited and buried in these geologic deposits. Treatment technologies that can change the character of the produced water depend on the initial produced water constituent profile and the profile needed for reuse and cost. Potential areas of reuse for treated produced water include oilfield, agriculture, and manufacturing. However, reuse of produced water is primarily associated with oilfield reuse. This is because there are few policies and regulations in place or being put in place for the use of treated produced water outside the oilfield. This is a topic of interest to various stakeholders in the over 30 oil- and gas-producing states in the USA. This chapter provides an overview of characteristics, treatment, and beneficial reuse of produced water plus some policy and regulatory considerations and stakeholder viewpoints.
