A new method of damage determination in geothermal wells from geothermal inflow with application to Los Humeros, Mexico

Abstract

Geothermal inflow type curves were obtained for different values of well damage (i.e., inflow performance relationships). The method was evaluated by diagnosing the damage of thirteen producing wells in the Los Humeros, Puebla, México geothermal field. Permeability determinations were carried out for these wells and their productivity indices were estimated. Comparison of the diagnoses made via damage effects against the results of field pressure tests showed that the maximum difference between both approaches is on the order of 0.7 damage units. The methodology allows reservoir characterization along its productive life, since several production tests are carried out while the reservoir is producing. The data obtained from production tests are used to determine the damage effect and permeability of the rock formation. Previously the damage (skin factor) could only be determined from the analyses of transient pressure tests.