Study and Application of Deep Profile Control and Oil Displacement Technology in the Fractured Tight Oil Reservoir

Abstract

In order to plug water channeling of fractured tight oil reservoir, a new type of copolymer as the main agent is used for deep profile control and oil displacement. This copolymer is synthesized with modified cellulose and acrylamide, which has relatively lower viscosity and can meet the requirements of injection into the formation. And it has good performance of shear resistance, which can migrate into the deep formation and maintain the good performance. And a gel, which is consisting of the copolymer and cross-linking agent, has a good performance under formation conditions. The gel strength and gelation time can be controlled to meet the requirements of construction. Oilfield construction shows that the way of multistage alternating injection of the profile control and oil displacement agent and formation water can push the gel into the deep formation and can plug the water channeling of fractures to improve the sweep efficiency with a wider range. After construction, the oil production is increased from 1.13 t/d to 4 t/d and the water cut is decreased from 98.16 % to 91.54 %. The results of laboratory experiment and field test show that the developed profile control and oil displacement agent and the way of multistage alternating injection are suitable for EOR of the fractured tight oil reservoirs.