Abstract
In this paper we discuss on forward modeling of the transient temperature responses during the well testing.
Well thermometry is conducted at all stages in the life of a reservoir: exploration, development, production and injection. Temperature measurements are especially informative ones when we use a transient processes in the well and formations.
The transient temperature variations in saturated porous medium are connected with fluid expansion/compression, heat convection, viscous dissipation and heat conduction. The combined viscous dissipation (frictional heating) and fluid expansion/compression terms comprise the barothermal effect. The barothermal effect is the same as the classical throttling (Joule-Thomson) one in the particular case of steady state flow. The value of the Joule-Thomson coefficient for oil is about (0.04–0.06) K/bar and for water is about 0.02 K/bar. Therefore the steady temperature variation in the oil inflow intervals (under the same pressure drop) is always more than in the water inflow intervals.
The temperature profile in well changes with time and depends on many other factors, including flow rate, fluid and formation properties and completion configuration. As the result the situation is possible, when specific flow rate of water is more than for oil and the inversion of the throttling temperature anomalies is observed. In this case during the time t less than inversion time tinv the water is heated more than oil. And it is observed the "normal" ratio of throttling anomalies for oil and water for time t>tinv.
Analytical and numerical models of barothermal effect in the saturated porous medium are developed. It was received the formulas for estimation of inversion time. It is suggested the technique of application of temperature anomalies inversion for the determination of water inflow intervals to well by thermal logs.
The field cases corroborate the real practical application of this phenomenon.
