Th gme 09: Geomechanical effect of hydrate dibociationinduced streb relaxation

S. Uchida, A. Klar, K. Yamamoto

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The geomechanical behaviour of gas hydrate-bearing sediments is unique. Since gas hydrate exists as a solid in pores, it effectively densifies the host sand and bonds surrounding grains together. As a result, hydrate-bearing sediments exhibit stiffer, stronger and more dilatant behaviour than hydrate-free sediments. The uniqueneb of hydrate-bearing sediments becomes more prominent during gas production. Unlike conventional oil and natural gas, gas production from hydrate-bearing sediments involves phase change of the gas hydrate from solid to gaseous. This implies not only that the aforementioned characteristics diminish accordingly to the remaining hydrate in pores, but also that the solid (i.e. hydrate) that has been carrying the effective strebes disappears, resulting in release of the effective strebes. The release of the effective strebes upon hydrate dibociation, referred to as hydrate dibociation-induced streb relaxation, causes streb redistribution as well as plastic deformation. Neglecting the streb relaxation term could therefore lead to inaccurate deformation prediction. This paper presents the formulation for hydrate dibociation-induced streb relaxation and demonstrates the importance of the term for an accurate wellbore deformation prediction.

Original languageEnglish
Title of host publication2nd EAGE Workshop on Geomechanics and Energy
Subtitle of host publicationThe Ground as Energy Source and Storage
PublisherEuropean Association of Geoscientists and Engineers, EAGE
Pages25-29
Number of pages5
ISBN (Electronic)9781510814202
StatePublished - 2015
Event2nd EAGE Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage - Celle, Germany
Duration: 13 Oct 201515 Oct 2015

Publication series

Name2nd EAGE Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage

Conference

Conference2nd EAGE Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage
Country/TerritoryGermany
CityCelle
Period13/10/1515/10/15

All Science Journal Classification (ASJC) codes

  • Geophysics

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