Estimation of undisturbed formation temperatures under spherical-radial heat flow conditions

Statistical evaluation of methods for the calculation of static formation temperatures in geothermal and oil wells using an extension of the error propagation theory

“…Spherical and radial heat flow method (SRM) Ascencio et al (1994) proposed a method to calculate SFT, which considers that the actual non-uniform, thermally perturbed zone around the borehole may be approximated as a spherical region of radius (r) and that the rock formation is infinite, homogeneous and isotropic with constant thermophysical properties, neglecting convection in the well. For modeling the thermal effects associated to well drilling and completion, the heat conduction equation under spherical and radial was solved by these authors.…”

“…(1) Line-source or Horner method (HM; Dowdle and Cobb, 1975); (2) Spherical and radial heat flow method (SRM; Ascencio et al, 1994); and (3) Cylindrical heat source method (CSM; Hasan and Kabir, 1994). Two purely conductive models (HM and SRM) and a more complex model that involves both conductive and convective mechanisms (CSM) were selected.…”

An Inverse Method for Estimation of Initial Temperatures in Geothermal Reservoirs: Part 2. Inverse Control Algorithm and Results of Application

“…(1) localization of fluid inflow regions or lost circulation zones, (2) estimation of heat reserves in a geothermal reservoir, (3) evaluation of geothermal gradients, (4) interpretation of electrical well logs, and (5) evaluation of in situ formation thermal conductivity (e.g., Grant et al, 1969;Ascencio et al, 1994;Takahashi et al, 1997;García-Gutiérrez et al, 1998, 2000.…”

“…Formation temperatures in a geothermal well can be obtained from: (i) empirical correlations (Farris, 1941); (ii) analysis of fluid inclusions (Fujino and Yamasaki, 1985); (iii) the inlet and outlet drilling mud temperatures (Takahashi et al, 1997;Osato et al, 2003), and (iv) temperature logs (Dowdle and Cobb, 1975;Ascencio et al, 1994). However, the more commonly used approach makes use of temperature logs obtained during well drilling.…”

Improved method for estimating static formation temperatures in geothermal and petroleum wells

“…In order to estimate the SFT using BHTs and shut-in times, we find numerous analytical methods (i.e. Horner, 1951;Ascencio et al, 1994;Hassan and Kabir, 1994;Kutasov and Eppelbaum, 2005;Zhou et 2015) and simulators (i.e. Beirute, 1991;García et al, 1998;Porkhial et al, 2015).…”