Analytical model of non-stationary temperature in heterogeneous reservoir

Abstract

The relevance of the research. At present time the interest in quantitative interpretation of temperature surveys is growing. Individual flow rate and reservoir pressure of each layer, behind-casing flow rate, hydrodynamic layer parameters, characterization of permeability changing at near-wellbore zone become the purposes of quantitative interpretation. Non-stationary temperature and pressure in the well are used as input data for transient processes analysis, and temperature logs are used for quasi-stationary analysis. Determination of individual layer flow rates and near-wellbore zone parameters are of particular interest. The main aim of the work is to develop and provide rationale for simplified analytical model of non-isothermal single-phase fluid filtration in heterogeneous reservoir. The methods used in the study. Analytical solution for temperature field in the layer after flow rate change is obtained by the method of characteristics. Two assumptions were made in solving the problem: radial thermal conduction and compressibility of saturated porous medium are ignored. Analytical models are compared with the numerical solution of the problem. The results. The paper studies the problem of unsteady temperature field in heterogeneous reservoir during fluid filtration. Radial heat conduction and compressibility of oil- or water-saturated reservoirs influence insignificantly the unsteady temperature field after the flow rate changes. It is possible to solve the inverse problem on evaluation of the damage zone radius of the permeability in the reservoir basing on the model curves of the temperature change after flow rate change. The paper gives a detailed algorithm for solving the inverse problem. The possibility of that method realization is demonstrated on model curves of the temperature change.

Keywords

• temperature
• pressure
• filtration
• convection
• thermal conduction
• compressibility