Civil Engineering ETDs

Publication Date

Summer 7-28-2026

Abstract

Considerable work has been conducted on modified wellbore cements, but a knowledge gap exists in the effects of downhole conditions on cement, especially tensile strength. In this study, a pressure vessel simulates representative downhole conditions (2000C, 1.5 MPa) with a reference solution for geothermal brine and naturally occurring geothermal gases. Samples are removed after 28-days for unconfined compressive strength testing, Brazilian tensile strength testing, elastic moduli measurement, and chemical analyses by X-ray diffraction and electron microprobe. Aqueous chemical analysis suggests multiple active reactions between the geothermal fluid and cement that are exacerbated by higher temperatures, but do not seem to affect strength at low temperatures. Silica flour-modified cements form silica-rich calcium silica hydrate (CSH) mineral phases (tobermorite, xonotlite) which are stronger in compression and tension than α-CSH phases. These results assist drilling professionals in understanding effects of geothermal conditions on cementitious materials when designing cement for a particular geothermal resource.

Keywords

geothermal, cement, wellbore, tensile

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Committee Member (Chair)

Micaela Mercuri

Second Committee Member

Jose Cerrato

Third Committee Member

William Kibikas

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