MULTISCALE MODELING OF THE POROELASTIC PROPERTIES OF VARIOUS OIL-WELL CEMENT PASTES

Evaluation of the poroelastic properties of oil-well cement paste is essential for prediction of the performance of the cement sheath during the life of a well. A multiscale homogenization model is used to evaluate the poroelastic properties of different classes of oil-well cement paste. The model has been calibrated in a previous work based on the results of a laboratory study on a hardened class G cement paste. A hydration model is used to evaluate the volume fractions of different microstructure phases of cement paste based on the chemical composition of clinker and the water-to-cement ratio. Typical chemical compositions of API class A to class H oil-well cements with their corresponding water-to-cement ratios are used to evaluate the poroelastic parameters such as drained bulk modulus, Biot coefficient, Skempton coefficient, etc. The results show that the difference in the chemical compositions of these cements has not an important effect on the variations of the poroelastic properties. Contrarily, the water-to-cement ratio has an important effect on the variations of these parameters.