关键词: 深层稠油油藏, 直井与水平井组合, 蒸汽+CO₂驱, 蒸汽吞吐, 提高采收率

Abstract: The physical simulation and numerical models were used to study the production mechanism of CO₂-assisted steam flooding process combined vertical and horizontal wells.The reduction of oil viscosity and oil swelling and decrease of oil-water interfacial tension were analyzed.The reasonable injection methods,injection ratio and injection amount of CO₂ and steam were optimized.The results showed that the proposed CO₂-assisted steam flooding process combined vertical and horizontal wells was available for deep heavy oil reservoirs after cyclic steam stimulation.Because the deep heavy oil reservoirs with the depth ranging from 1 300 m to 1 700 m have a lot of heat loss in well bore and lower steam quality at well bottom,by means of adding CO₂ in steam flooding process,the steam flooding can achieve good performance under the lower steam quality conditions,and the quick response can be obtained after changing the cyclic steam stimulation into steam flooding.

Key words: deep heavy oil reservoir, combined vertical and horizontal wells, CO₂-assisted steam flooding, cyclic steam stimulation, enhanced oil recovery