Total Se

Total Sa

Jean Sulem

André Garnier

Christophe Urbanczyk

Nicolaine Agofack

Siavash Ghabezloo

Axel-Pierre Bois

Manh-Huyen Vu

Siavesh Ghabezloo

Jean-Benoit Laudet

Jean-Benoît Laudet

A method for determining a plasticity parameter of a hydrating, cement paste by mixing the components to obtain a cement slurry, pouring the cement slurry in a scaled oedometric cell, and performing an oedometric measurement operation within a predefined early-age time interval by applying a predefined axial stress path to the cement slurry over a predefined measurement duration and measuring an axial strain. A plasticity parameter of the hydrating cement paste is determined b a calibration processing operation comprising providing an initial value of a plasticity parameter of an elastoplastic model of hydrating cement paste, determining simulated axial strain values by solving the elastoplastic model of hydrating cement and comparing the simulated axial strain values with the axial strain measurements of the cement slurry.

Method for determining a plasticity parameter of a hydrating cement paste

The present invention relates to a method for determining a time window in which a casing pressure test can be performed without damaging a cement sheath. The time window is determined by: determining the hydration degree of the cement at a given time for a considered pressure and temperature values in the well; and then comparing the determined hydration degree to a predetermined value. If the determined hydration degree is below the predetermined value, then the casing pressure test can be done without damaging the cement.

Method for determining a time window in which a casing pressure test can be performed without damaging a cement sheath

The present invention relates to a method for determining mechanical parameters of a cementitious system, on the basis of time, and on the basis of the fineness of the cementitious system, pressure and/or temperature, representative of the in situ conditions found in wellbores. The initial composition of the cementitious system, the fineness &#x3a6; thereof and the speed of the compression waves on the basis of time V(t) are the only input data of the method. Said method comprises: &#x25aa; a step A of estimating the degree of hydration of the cementitious system on the basis of time &#x3b1;(t) from Vp(t), at a pressure Pand a temperature T; &#x25aa; a step B wherein &#x3b1;(t) is determined on the basis of desired values of fineness &#x3a6;n of the cementitious system, pressure Pn and/or temperature Tn; &#x25aa; a step C wherein the composition of the cementitious system is determined on the basis of time C(t) and on the basis of desired values of fineness &#x3a6;n of the cementitious system, pressure Pn and/or temperature Tn from &#x3b1;(t) determined in step B; &#x25aa; and a step D of determining at least one mechanical parameter of the cementitious system on the basis of time and on the basis of desired values of fineness &#x3a6;n of the cementitious system, pressure Pn and/or temperature Tn, from C(t) determined in step C. According to the method of the invention, these parameters can be determined while the cementitious system is still very young. In particular, the parameters of static deformability and hydro-mechanical coupling parameters are determined by the method according to the invention.

Method for characterising the mechanical behaviour of cements

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Paris, France

Jean Sulem