L52296 Smart Gas Using Chemicals To Improve Gas Deliverability Phase II

The objective of this effort was to demonstrate in the field the new wettability altering technology developed in the laboratory during Phase 1. Reservoir cores from three gas storage facilities including sandstone and dolomite reservoirs were used to evaluate the two surfactants. The imbibition and core flood tests showed that gas deliverability was improved in surfactant-treated sandstone cores. It was concluded that the aquifer storage facilities are candidates for field testing. Results from Phase I provided the foundation for this Phase II project. The Waverly Storage Facility operated by Southern Union/Panhandle Energy was selected as the site for a field test of the surfactant process. Waverly is an 1800-ft sandstone aquifer gas storage reservoir located near Springfield, lllinois. Expansion and contraction of a spherical gas bubble provided pressure support as gas was injected and withdrawn from 37 individual wells. Three wells were selected for treatment with 1000 bbl of ~4% surfactant solution. An additional three nearby wells were selected as control wells. A field mixing procedure similar to that used in the laboratory to avoid phase separation of the microemulsion was developed and successfully used during the third week of October 2007 when the wells were treated. Rates and pressures were measured at the wellhead; fluid levels were not recorded. Since the initial rate-pressure data collected during the project year including the well treatments were sparse, it was decided to extend the project to the end of 2008 to acquire more field data.