Temperature Distribution Modeling in Geothermal Wellbore and Formation During the Well Test

摘要

The physical property and rheological behavior parameters of fluid in the wellbore are sensible functions of temperature. Hence, exact calculation of temperature distribution is basement of predicting the pressure distribution, proceeding optimization procedure and analysis of its behavior. The formation temperature is calculated by single geothermal gradient hardly describes the initial formation temperature because of the different temperature variation in cap rock and reservoir. This paper calculated the initial formation temperature by Honer Method, analyzed heat transfer process in wellbore and formation, considered the convection effect of groundwater in the aquifer, established a mathematical model which included steady-state heat transfer in the wellbore and unsteady-state heat conduction in the formation. Based on the model, ZK212 in Yangyi Geothermal Field, Tibet, was taken as an example to calculate the fluid temperature in the wellbore, simulated the sensitivity analysis by assumed parameters, such as well diameter, outflow, thermal conductivity of cement, impacted on the wellhead temperature, and optimized the wellhead temperature.