UPPER LAYER HEATING SYSTEM AT DUAL COMPLETION

Abstract

At a late stage of oil field development under declining profitability of production, dual completion of layers, varying in geological and filtration characteristics, is particularly relevant. The paper considers ways to improve the efficiency of a single-lift dual completion installation for the operation of two layers with rod and electric centrifugal pumps. A variant of dual completion with the upper layer operated by a rod pump, includes the possibility of natural heating of the bottom-hole zone of the upper layer due to the thermal energy of the lower layer liquid. To increase the efficiency of heat exchange, an improved design of an installation with a heat exchange device in the upper productive layer interval is proposed. In order to study the optimal geometric and technological parameters of the heat exchanger in system well-heat exchanger-productive, the temperature field was simulated. It is theoretically proved that the use of a heat exchanger contributes to an increase in the intensity of heat transfer from the lower layer liquid passing through the heat exchanger to the upper layer liquid in the inter-tube space. The increase in heat transfer efficiency is due to an increase in the surface of the heat exchange device due to fins placed on the side surface of the heat exchanger housing. The optimal value of the height of the plates for which the maximum heating of the liquid in the inter-tube space in the upper layer interval is achieved is calculated. It is shown that a set of interrelated processes (acceleration of flow motion and increase in hydrodynamic friction due to a decrease in the diameter of the body relative to the diameter of the tubing, turbulence when passing through a swirler), provided by the heat exchanger device, contributes to increase the temperature of the liquid in the heat exchanger and increase its efficiency. The influence of the internal cross-section of the heat exchanger body on its surface temperature is studied. As a result of taking into account two factors that are opposite in efficiency: a positive one (an increase in the speed of the liquid in the heat exchanger and an increase in the temperature on the surface the heat exchanger housing when the housing diameter decreases) and negative (increase in hydraulic losses in the heat exchanger and the head of the electric centrifugal pump) the optimal diameter of the heat exchanger housing is selected.