Analysis of SPR salt cavern remedial leach program 2013.

Abstract

The storage caverns of the US Strategic Petroleum Reserve (SPR) exhibit creep behavior resulting in reduction of storage capacity over time. Maintenance of oil storage capacity requires periodic controlled leaching named remedial leach. The 30 MMB sale in summer 2011 provided space available to facilitate leaching operations. The objective of this report is to present the results and analyses of remedial leach activity at the SPR following the 2011 sale until midJanuary 2013. This report focuses on caverns BH101, BH104, WH105 and WH106. Three of the four hanging strings were damaged resulting in deviations from normal leach patterns; however, the deviations did not affect the immediate geomechanical stability of the caverns. Significant leaching occurred in the toes of the caverns likely decreasing the number of available drawdowns until P/D ratio criteria are met. SANSMIC shows good agreement with sonar data and reasonably predicted the location and size of the enhanced leaching region resulting from string breakage. 4 ACKNOWLEDGEMENTS

Literature Survey Concerning the Feasibility of Remedial Leach for Select Phase I Caverns

“…Prior to this working group meeting, it was thought that withdrawal leach focused leaching near the OBI. This was found to not be true as withdrawal leach focuses leach near the injection depth and tapers up to the final OBI depth (is a function of time exposed to under saturated brine) (Lord, Roberts et al 2012;Weber, Gutierrez et al 2013;. A plan was proposed where selected Phase II and III caverns could be leached with targeted sculpting in the middle depths of the caverns, and the resulting work was published in a Sandia/DM joint working group technical report (Eldredge, Checkai et al 2013).…”