Evaluation of the productivity of geothermal wells by analyzing production measurements and the damage effect

Summary In this work, an analysis of production data for determining the damage effect in geothermal wells is reported. Measurements of some Mexican geothermal wells have been analyzed for evaluating the decrease of their productivity under exploitation conditions. As an innovation of the methodology used in this work, the dimensionless well flow parameters (pressure and mass flow rate), and the inflow performance relationship curves of producing wells were determined by using more representative thermodynamic properties of the geothermal fluid (i.e., characterized as a ternary compound system: H2O–CO2–NaCl). Geothermal inflow type-curves were therefore used for determining the wellbore damage effect. Production measurements of the wells were compiled at different stages of their operative life cycle. From this study, it was found that the wellbore damage effect increases with the exploitation time. These results enable a drop in the fluid flow mechanisms of the wells to be identified. The quantitative knowledge of the wellbore damage effect helped us to define a technical criterion for the decision making of the most appropriate engineering operations to be applied (e.g., cleanings, repairs, stimulations, fracturing, etc.) either to recover or to improve the well productivity. Copyright © 2016 John Wiley & Sons, Ltd.