The effect of undrained heating on a fluid-saturated hardened cement paste

TL;DR

This paper investigates how rapid undrained heating affects volume change and pore pressure in hardened cement paste, crucial for understanding oil well cement integrity under thermal stress.

Contribution

It presents experimental measurements of thermal pressurization and expansion coefficients, and analyzes the anomalous thermal behavior of cement pore fluid under undrained heating.

Findings

Thermal pressurization coefficient is 0.6 MPa/°C.

Measured drained and undrained thermal expansion coefficients.

Identified anomalous thermal behavior of cement pore fluid.

Abstract

The effect of undrained heating on volume change and induced pore pressure increase is an important point to properly understand the behaviour and evaluate the integrity of an oil well cement sheath submitted to rapid temperature changes. This thermal pressurization of the pore fluid is due to the discrepancy between the thermal expansion coefficients of the pore fluid and of the solid matrix. The equations governing the undrained thermo-hydro-mechanical response of a porous material are presented and the effect of undrained heating is studied experimentally for a saturated hardened cement paste. The measured value of the thermal pressurization coefficient is equal to 0.6MPa/°C. The drained and undrained thermal expansion coefficients of the hardened cement paste are also measured in the heating tests. The anomalous thermal behaviour of cement pore fluid is back analysed from the results of the undrained heating test.