ESTIMATION OF TEMPERATURES IN GEOTHERMAL WELLS DURING CIRCULATION ANDSHUT-IN IN THE PRESENCE OF LOST CIRCULATION

The estimation of temperatures in and around a geothermal well during circulation, and during shut-in conditions in the presence of lost cir culation is presented in this work. Estimated temperatures are compare d with temperature logs measured during drilling stoppages. Temperatur es were estimated using a computer code specifically developed to acco unt for the transient convective heat transfer due to lost circulation in the rock surrounding a well. This feature of the present code is i mportant since wellbore simulators normally consider the heat transfer process in the rock as a merely conductive problem. The code is capab le of accounting for these losses at any point in the well and applica tion was made to the study of two Mexican geothermal wells (well LV-3 from the Las Tres Virgenes field and well EAZ-2 from the Los Azufres f ield). The results show that the effect of lost circulation on the shu t-in temperature profiles can be modelled satisfactorily. Research is under way to improve the present methodology.