Experimental Study on Flow Characteristics of Oil-Water Two-Phase Flow in Single-Node Cross Fracture

Abstract

Single-node cross fracture is the basic unit of discrete fracture network. In this paper, the flow characteristics of oil-water two-phase flow in single-node cross fracture model are investigated by experimental method. The model was divided into sixteen groups according to different angles, the oil and water phase flow rates were changed sequentially in each group and the velocity of oil and water phase were controlled to be in the low velocity flow rate range all the time during the experiment. The fluid flow process was recorded during the experiment by using the high-speed camera and the results were analyzed in detail. Under the condition of low velocity flow, oil-water two phases were slug flow in fracture. Effects of fracture crossing angle and oil-water phase velocity on the length of water section and the ratio of water-oil section length were also considered. The peristaltic pump speed is used instead of flow rate for the discussion, and the results show that for the same cross-fracture angle model, when the water pump speed is unchanged, the length of the water section gradually decreases in the form. of a power function with the increase of the speed of the oil pump. When the oil pump speed is unchanged, as the water pump speed increases, the length of water section increases in the form. of a linear function and the length ratio of wateroil section increases in the form. of the power function. Under different speeds of oil pump and water pump, the influence of fracture crossing angle on the length of water section and the length ratio of water-oil section is different.