Temperature Effects on Stiffness Moduli of Reservoir Sandstone from the Deep North Sea

Tobias Orlander, Katrine Alling Andreassen, Ida Lykke Fabricius

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Abstract

We investigate effect of testing temperature on the dynamic frame stiffness of quartz-bearing North Sea sandstone from depths of 5 km. We show that at low stress levels, the rock frame stiffens with increasing temperature and we propose an explanation for the controlling mechanisms. While equilibrating to atmospheric conditions, cooling and stress release of reservoir material can induce tensional forces in the rock frame leading to ruptures of the contact cement in the weakest grain contacts. The frame stiffness hence reduces, as the ruptures are permanent. However, a fraction of the in-situ stiffness can be restored by reestablishment of reservoir stress or temperature, but only as recovery of contact between ruptures and not as re-cementation. In literature, ruptures of contact cement are denoted as micro-cracks, strictly posing a bulk term, without distinguishing effects of stress from temperature. This is unfortunate and hence, we designed a testing program with the intension of separating and quantifying effects of temperature and stress, specifically for the sandstone material subject to this study.
Original languageEnglish
Publication date2017
Number of pages5
Publication statusPublished - 2017
Event51st US Rock Mechanics / Geomechanics Symposium - San Francisco, United States
Duration: 25 Jun 201727 Jun 2017
Conference number: 51

Conference

Conference51st US Rock Mechanics / Geomechanics Symposium
Number51
CountryUnited States
CitySan Francisco
Period25/06/201727/06/2017

Cite this

Orlander, T., Andreassen, K. A., & Fabricius, I. L. (2017). Temperature Effects on Stiffness Moduli of Reservoir Sandstone from the Deep North Sea. Paper presented at 51st US Rock Mechanics / Geomechanics Symposium, San Francisco, United States.