| Title | Thermal Evolution Study of the LV-3 Well in the Tres Virgenes Geothermal Field, Mexico |
|---|---|
| Authors | Edger Santoyo, A. Garcia, G. Espinosa, E. Gonzalez-Partida and J.C. Viggiano |
| Year | 2000 |
| Conference | World Geothermal Congress |
| Keywords | lost circulation, drilling, shut-in, static formation temperature, Las Tres Virgenes geothermal system |
| Abstract | A thermal evolution study of the LV-3 geothermal well (depth: 2150 m) is presented. Such a study is based on wellbore temperature logs, transient temperature profiles (obtained from numerical modeling of the heat transfer processes during well drilling and shut-in) and fluid inclusion logging. Drilling and shut-in temperature profiles were predicted by use of a transient wellbore thermal simulator which considers conductive and convective heat transfer processes. Such a numerical simulation considered the LV-3 well geometry in the presence of fluid losses into the formation. Thus, numerical simulation enabled the drilling and shut-in thermal history of well LV-3 to be closely reproduced. Precision temperature logs from LV-3 well (at 402-m and 2000-m) provided information on the location of permeable zones intersecting the wellbore. Such permeable zones were partially identified at a wellbore depth of 400-m and more significantly between 1300-m and 1600-m. Microthermometric determinations on well cuttings and core samples containing veins filled with secondary minerals (epidote, quartz and calcite) were also carried out. Minimum homogenization temperatures ranging from 109 ?C to 125 ?C were measured in the first 920 m deep. Between 1830 m and 2150 m deep, the minimum homogenization temperatures ranged from 256 ?C to 268 ?C. Likewise salinity concentration ranges from 3.4 to 18.5 wt% as NaCl equivalent were found. Static formation temperatures were also computed by five analytical methods which are the most commonly used in the geothermal industry: the classical Horner plot, the improved Horner, the two-point method and the spherical-radial and cylindrical-radial heat flow models. A comparison among the wellbore temperature logs, the homogenization temperatures, and the transient temperature profiles is also presented. |