Correlation of Sonic Log Values to Strength in Salt

Abstract

Gas storage wells have been drilled in Halifax, Nova Scotia, Canada. One of these wells was cored from top to bottom penetrating about 500m of salt at 460 meters vertical depth. To obtain unconfined compressive strength (UCS), 18 intervals were tested with a total of 389 point load tests. Of the 61 tests, 18 intervals and 126 point load tests were done in intervals containing salt. The corresponding sonic log values from the same depth interval as the tests were used to calculate UCS values from existing correlations. The UCS values obtained from the available sonic log correlations matched well with the point load tests in most formations except for those containing salts. New correlations were developed from the point load tests and the corresponding sonic data for salt and are published in this paper. The new correlations show a reasonable match and provide a new tool for obtaining UCS values for salts from sonic logs. It should be noted that these new correlations require additional verification but should serve as a good starting point for subsequent wellbore stability analysis.

Meeting Name

42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium (2008: Jun. 29-Jul. 2, San Francisco, CA)

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Gas Storage; Halifax , Nova Scotia; Log Correlation; New Correlations; New Tools; Point Load Tests; Sonic Logs; Unconfined Compressive Strength; Wellbore Stability Analysis; Acoustic Logging; Boring; Compressive Strength; Rock Mechanics; Salts; Wells, Testing

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2008 Society of Petroleum Engineers (SPE), All rights reserved.

Publication Date

01 Jun 2008

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