Five Phase I projects (completed) carried out modeling and other analyses to support development of pressure management strategies for potential field projects, focusing on five areas/formations representing important potential geologic storage opportunities in the United States. The modeling studies showed how the reservoir characteristics of the various potential storage formations would impact pressure reduction achieved for various injection/extraction scenarios. Life cycle analysis (LCA) studies performed by the projects highlighted the likelihood of encountering very high total dissolved solids (TDS) brines in many saline formation storage projects, as well as the challenges of handling these brines. Overall results from the Phase I Feasibility Evaluation includes the following:

• LCA studies on extracted brine-handling options suggest that an underground injection control (UIC) well has a lower environmental impact than brine treatment because brine treatment requires removal of suspended solids from the extracted brine.
• Minimizing transportation distances, brine disposal costs (via volume reduction), and pre-treatment costs are important components of cost control.
• Modeling results showed that passive extraction is not as effective as active extraction and it comes with higher investment (double the number of perforated wells is needed), but for sites where brine treatment cannot be done or can be done at a small scale only, passive extraction could be the favored option in order to reduce the large volumes of brine brought up to surface using active extraction.
• Maximizing the extraction of fresh water from the brine stream will greatly reduce disposal costs (and transportation costs), unless a market is found for “clean brine” products.

Two projects have advanced to Phase II (ongoing) to validate brine extraction strategies through injection/extraction of brine and monitoring of differential pressures at active wastewater disposal facilities. Both Phase II projects also host facilities for testing emerging enhanced water recovery (EWR) technologies. Working at field sites provided by industrial partners, the research involves the injection and extraction of brine from deep saline formations, predictive modeling of the differential pressure plume (differential pressure is defined as the difference in pressure at a point in the reservoir before and after injection begins) and monitoring to validate pressure management approaches. Extracted brines will be utilized as a part of a test bed for brine treatment technologies. Phase II projects are being carried out in the Williston Basin and Gulf Coast.