The objective of this work is to investigate the behavior of a coupled wellbore-gas-reservoir system. Initially, the system is at static conditions and may flow at constant surface rate. Non-isothermal flow is considered in the reservoir and in the tubing string. The partial differential equations and auxiliary conditions which govern the flow in the reservoir are coupled with the wellbore equations - modified by the method of characteristics - using a finite difference scheme. Results of pressure and temperature versus time can be displayed in many different positions. Particularly, the downhole wellbore flowing pressure, usually used in well test analysis, is investigated in depth. A damaged region around the well is considered. Comparison with isothermal systems showed that for long-time flow regimes the conventional semilog analysis is of good accuracy. However, for short-time analysis influenced by wellbore storage significant errors may occur which depend upon the flow parameters and thermal properties of the system.

You can access this article if you purchase or spend a download.