Prediction of pressure and temperature profiles for two-phase flow in multilayered gas wells by DTS data

Abstract

Downhole temperature and pressure data are crucial information to help us understand the fluid flow dynamics in the reservoir. With the advancement of downhole monitoring technology, high-precision and high-resolution monitoring instruments facilitate qualitative and quantitative utilization of transient downhole temperature and pressure data in monitoring applications. The distributed temperature sensors (DTSs) overcome the limitations of traditional monitoring techniques and achieve real-time temperature monitoring in complex downhole conditions. However, the physical phenomena and response mechanisms hidden in the temperature data obtained by (DTSs) in transient, multilayered combined production and two-phase gas wells have not been thoroughly studied yet.Gas-water two-phase fluid flow in the reservoir is the prime consideration of this study. In this paper, based on the principles of mass, energy conservation, Darcy's law, and the second laws of thermodynamics, a forward model is established to predict pressure and temperature distribution in a multilayered vertical gas well system by coupling the flow model and thermal model. The model considers the changes of fluid high-pressure properties and microheat effects such as the Joule-Thomson effect, viscous friction to reach the desired solution. Subsequently, the model is solved numerically and used for sensitivity analysis of parameters influencing temperature and pressure distribution, such as gas production rates, permeability, Joule-Thomson coefficient. At last, the model is applied to a multilayer combined production well. The results of the example show the pressure, temperature and production profile can be predicted precisely.