An investigation into the heat transfer process in petroleum wells, and a comprehensive modeling study investigating the temperature distribution in production wells

Abstract

When producing hot fluid from a reservoir, the production well experiences changing temperatures with depth for the different tubing, casing, cement and wellbore interfaces. To what extent the temperatures change is depending on many factors. The production flow rate, produced fluid specific heat capacity, thermal conductivity and viscosity of the annular fluids, the Joule-Thomson effect on the produced fluid, radius of the wellbore, annular clearance, and production time, are some of the parameters playing an important role in determining the heat transfer across the wellbore between the produced fluid and the formation. A wellbore heat transfer model for a single phase oil production scenario, based on the wellbore heat transfer model presented by Hasan, Kabir, and Wang (2009), has been implemented in the MATLAB ® software. The model considers a fairly complex wellbore configuration, consisting of five wellbore sections of different configuration, with the possibility of natural/free convection taking place in three brine filled annulus. Correlations taking temperature and/or pressure into consideration has been implemented for all thermophysical properties in the wellbore, such as thermal conductivity of tubing, casing, and cement, specific heat capacity, viscosity, thermal conductivity of annular fluids, and densities of produced and annular fluids, to mention some. The MATLAB program allows for custom well configurations, and is able to calculate the temperatures at all the wellbore, casings and tubing interfaces, and has the ability to use other fluid, casing/tubing, cement and formation properties than the ones used in this study.