PR-244-18702-R01 Evaluation of Casing Integrity for Underground Storage Wells

Abstract

This work was funded in part, under the Department of Transportation, Pipeline and Hazardous Materials Safety Administration. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Pipeline and Hazardous Materials Safety Administration, the Department of Transportation, or the U.S. Government. C-FER Technologies (1999) Inc., ("C-FER") conducted a multi-phase study to further advance the ability to predict the remaining casing burst capacity for underground natural gas storage wells. This project is co-funded by the Pipeline Research Council International, Inc. (PRCI) and the US Department of Transportation (DOT), Pipeline and Hazardous Materials Safety Administration (PHMSA). This project included a literature review of casing corrosion logging technologies and remaining burst capacity prediction models. Three casing corrosion logging tools, selected based on the outcome of a preceding PRCI casing logging tool test program, were tested to further evaluate their performance in detecting and sizing various metal loss features on casing specimens. Physical burst tests with capped ends were conducted on 20 specimens selected from the logged casing joints to benchmark the burst prediction models. Advanced finite element analysis (FEA) was also performed to evaluate the effect of in-situ downhole load conditions on the remaining burst capacity of corroded casing. A reliability-based framework was outlined to quantitatively address various uncertainties associated with the casing corrosion integrity management. This report summarizes the work completed, the key results and conclusions, as well as recommendations for future initiatives.