On size-dependent uniaxial compressive strength of sedimentary rocks in reservoir geomechanics

H. Roshan, H. Masoumi, P. C. Hagan

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

19 Citations (Scopus)

Abstract

The uniaxial compressive strength (UCS) of sedimentary rocks is one of the key parameters in petroleum related geomechanical projects from hydraulic fracturing to the estimation of in-situ stress magnitudes. Due to the scarcity of the rock samples the UCS is often correlated to the interval transient time (equivalent to P-wave velocity) for the field applications, however; the size-dependency of UCS seems to be overlooked in such applications. While the conventional understanding of UCS-size dependency is that the UCS of intact rock decreases with an increase in sample size, recent studies have shown that the UCS increases with an increase in sample size up to a characteristic diameter and then decreases afterward (ascending-descending behavior). Therefore, in this study, a set of uniaxial compressive tests were conducted on shale samples having different diameters. The obtained results were combined with those available in the literature and the Unified Size Effect Law was then fitted to the whole data set. A generalized correlation was proposed for extrapolation of the UCS of rock formations from the USC of rock sample having 25 mm diameter. The calibration of a UCS-interval transient time correlation is also given for the shale sample as a practical example. Finally, it was suggested that the procedure proposed here is adopted as a standard practice in petroleum related geomechanical projects for higher accuracy in design processes.

Original languageEnglish
Title of host publication50th US Rock Mechanics / Geomechanics Symposium 2016
PublisherAmerican Rock Mechanics Association (ARMA)
Pages2322-2327
Number of pages6
Volume3
ISBN (Electronic)9781510828025
Publication statusPublished - 2016
Externally publishedYes
EventUS Rock Mechanics / Geomechanics Symposium 2016 - Houston, United States of America
Duration: 26 Jun 201629 Jun 2016
Conference number: 50th

Conference

ConferenceUS Rock Mechanics / Geomechanics Symposium 2016
Country/TerritoryUnited States of America
CityHouston
Period26/06/1629/06/16

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