关键词: 红河油田, 致密油藏, 注CO₂开发, 物理模拟实验, 技术界限

Abstract: Honghe oilfield is a typical ultra⁃low porosity and tight oil reservoir, and it is difficult to use conventional water injection development method economically and effectively. By using indoor physical simulation experiments, the feasibility of CO₂ flooding method in Honghe oilfield was explored from the aspects of compatibility of CO₂ with crude oil and reservoirs, formations injection capacity and reservoir injection limits. The results show that CO₂ fluids injection in the reservoirs of Honghe oilfield does not block and the compatibility of CO₂ with reservoir crude oil is good. Under the same permeability, the CO₂ flooding injection index is 8 times of the water injection index, and the CO₂ injection is a relatively stable process. The breakthrough time of CO₂ injection is relatively longer than N₂ injection. At the lower permeability stage, there is no rapid breakthrough; combined with non⁃linear percolation and constant⁃velocity mercury injection experiment technology, we find pressure gradient of CO₂ injection is obviously increased when the permeability is lower than 0.08 mD. It is determined that 0.08 mD is the lower limit of reservoir permeability for CO₂ injection. The comprehensive experimental results show that the development of CO₂ injection in the Honghe tight reservoir is technically feasible.

Key words: Honghe oilfield, Tight oil reservoir, CO₂ fooding, Physical simulation experiments, Technological limits