Produced water management via injection, to disposal zones or re-injected into the source oil zone (PWRI), is being increasingly regarded as the best practicable environmental option - far preferable to discharge to the sea or evaporation ponds in the desert.
However, underground injection is not without its dangers and reservoir fracture control is a vital issue for many projects. The planning for and control of injection, either above or below fracture pressure, requires good, project-specific data on water quality and rock properties as inputs to injection simulation programs. Even so, these programs are currently subject to intensive research, especially for soft sands, layered formations and horizontal wells.
Research is on-going too in the areas of damage mitigation and stimulation of PWRI wells, and well failures do occur. In consequence, it is necessary to adequately monitor both well performance and injection water quality, and have in place contingency plans in case of a failure of the injection system. On-line monitoring of water quality may help avoid well damage/failure, and may also enable the upstream separation processes to be operated at their highest efficiency.