TEMLOPI/V.2: a computer program for estimation of fully transient temperatures in geothermal wells during circulation and shut-in

This paper describes the development, validation and application of the TEM LOPI/V.2 computer program. This program is a useful tool for estimating in- situ the transient temperature distribution of the fluids employed for dril ling geothermal wells, TEMLOPI/V.2 is based on a mathematical model which i s developed to consider two-dimensional transient heat transfer during dril ling and shut-in conditions in and around a geothermal well. The solution o f the partial differential equations is based on the finite-difference tech nique with an implicit scheme. This scheme serves to demonstrate the numeri cal solution procedure. Each radial grid node is placed in a different ther mal region: flow inside the pipe, metal pipe wall, flow inside annulus, and the surrounding formation. The program was written in FORTRAN 77 using mod ular programming and runs on most IBM compatible personal computers. The so ftware code, its architecture, input and output files, the solution algorit hm, flow diagrams and source programs are described in detail. From validat ion tests, computed temperatures differ by less than 5 degreesC from analyt ically obtained temperatures. Comparison of results from the fully transien t TEMLOPI/V.2 simulator and the pseudo-transient version, TEMLOPI/V.1, with measured data shows that the fully transient model provides better results . Application of TEMLOPI/V.2 is demonstrated in a practical application stu dy of well EAZ-2 from Los Azufres Mexican geothermal field, (C) 2001 Elsevi er Science Ltd, All rights reserved.