(651g) Spatio-Temporal Distribution of Water Recovery Ratio in Eagle Ford and Marcellus: Its Effect on Shale Gas Supply Chain Network

Natural gas is playing an important role in meeting current global energy demand. Due to the constantly developing horizontal drilling and hydraulic fracturing technologies in recent years, unconventional shale gas production has significantly increased, and become the major contributor to the total natural gas supply in the United States. However, while this “shale revolution” has led enhanced natural gas production and created tremendous opportunities for monetization into value-added fuels and chemicals [1], it has simultaneously generated great environmental concerns; particularly, the acquisition of freshwater required for drilling and hydraulic fracturing operation, and management of wastewater generated along with shale gas [2], [3].

In this regard, several recent studies have incorporated optimization techniques to develop effective water management strategies in shale gas development [4]–[8], and evaluated the amounts of water-use and flowback and produced (FP) water in major unconventional shale gas and oil regions [9]–[11]; however, very few studies considered the spatio-temporal variability in the amounts of water-use for hydraulic fracturing and FP water production, although it can decisively affect the optimal design and configuration of shale gas supply chain network (SGSCN).

Motivated by these considerations, we systematically presented the water recovery ratios (i.e., the ratio of cumulative FP water volume at each time period to water-use volume) of shale gas wells drilled in the Eagle Ford and Marcellus shale regions, and utilized a SGSCN optimization model to demonstrate how the water recovery ratio affects its design and configuration. Initially, we collected water-use volume and monthly FP water production volume data for shale gas wells available in the two shale regions. Second, the data from multiple database sources were post-processed and integrated to calculate the water recovery ratios. Third, the obtained water recovery ratio data were analyzed according to the associated location and production history information to study their underlying spatio-temporal variation across multiple counties over multiple time periods in each shale region. Fourth, a SGSCN optimization model from the literature was utilized to perform two case studies in the Marcellus, where two groups of wells with similar water-use volumes but different water recovery ratios were considered. It shows that the water recovery ratios of shale gas wells vary significantly across counties, although they are within the same shale region; therefore, significantly different optimal SGSCN configurations were required for economically desirable and practically feasible management of shale gas wells with different water recovery ratios.

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