Numerical modeling of high-temperature deep wells in the Cerro Prieto geothermal field, Mexico

Abstract

A numerical modeling study of three non-producing deep geothermal wells from Cerro Prieto is presented. We compute the expected production characteristics of these wells in order to determine if their inability to sustain flow was due to (i) heat loss effects in the well, (ii) the influence of production casing diameters, (iii) the transient heat loss during the first few days of well discharge, or (iv) the effect of secondary low-enthalpy inflows. A new version of the wellbore flow simulator called GEOPOZO v2.0 was developed to solve the equations of conservation of mass, mo- mentum and energy for steady or transient one- and two-phase flow in geothermal wells. It was found that all three wells should have sustained production. The early heat losses were so large that the wells need to be induced and they would only sustain flow after several days of induced discharge. For well M-202 the match between measured and computed temperature profiles for a secondary feedzone suggests that the inflow of colder waters was responsible for stopping the flow of this well.