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6008569 
Journal Article 
Modeling geothermal energy efficiency from abandoned oil and gas wells to desalinate produced water 
Kiaghadi, A; Sobel, RS; Rifai, HS 
2017 
Yes 
Desalination
ISSN: 0011-9164 
414 
51-62 
WOS:000402946500007 
This study investigated the use of low temperature geothermal resources to convert salty produced water into a freshwater resource. The research retrofits soon-to-be-shut-down oil and gas wells as geothermal wells, simultaneously overcoming drilling costs and scale formation by using a freshwater closed loop system for thermal energy delivery. Heat transfer modeling was combined with water treatment thermodynamics to develop a predictive tool that can be used to estimate daily deliverable treated water. Results indicated that the developed model was most sensitive to well depth, geothermal gradient, and total dissolved solids in the produced water. Results also indicated that a 4000m deep well with a geothermal gradient of 0.05°C/m can successfully treat produced water with as high as 170,000mg/L total dissolved solids and still deliver almost 600,000L of clean water per day. An illustrative demonstration indicated that in the Eagle Ford Shale in Texas, >60% of the drilled basin area can deliver at least half a million liters of treated water daily under ideal conditions. This is particularly meaningful as Texas experiences extended periods of drought and the treated produced water would represent a new and resilient source of water. 
Heat transfer; Water treatment; Total dissolved solids; Shale; Permian Basin; Eagle Ford Shale