Open AccessEstimation of formation temperature from borehole measurements
Author(s) -
Luheshi M. N.
Publication year - 1983
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1983.tb01902.x
Subject(s) - borehole , geology , induced seismicity , convection , geothermal gradient , disturbance (geology) , thermal , geophysics , heat transfer , convective heat transfer , fluid dynamics , flow (mathematics) , drilling , seismology , mechanics , geotechnical engineering , meteorology , geomorphology , materials science , physics , metallurgy
Summary. A new numerical method is described for modelling the thermal disturbance around a borehole and a comparison is made with the commonly used line source model. The numerical model generally gives an estimate of the equilibrium formation temperature which is up to about 20 per cent higher than the ‘Horner plot’ method. The relaxation of the borehole temperature is sensitive to the contrast between the thermal properties of the drilling fluid and of the surrounding rock as well as to the disturbance time. The importance of vertical temperature gradients and fluid motion (both free convection in the borehole and flow in the formation) is also examined. It is found that vertical temperature gradients are unlikely to be important provided temperatures are measured more than 10 borehole radii above the bottom. Convective heat transfer can be important under some drilling conditions.