特低渗透油藏CO2驱油调整技术界限

Technical limits for the adjustment of the CO2 flooding in ultra-low permeability oil reservoirs

大庆外围油田CO2驱油试验开展了10多年,针对当前调整技术存在一些不适应性,开发过程中暴露出来的气窜严重、受效差和受效不均匀、单一数值模拟计算的调整界限参数不够精确指导开发调整等问题,研究了影响CO2驱油效果的6个彼此相互关联的调整技术界限:流动压力、注气压力、注气速度、地层压力、注采比、气油比。选取典型代表S101试验区,应用数学计算方法与数值模拟相结合确定相应技术界限参数,通过加权平均法,得到了符合油藏开发现状问题的精准特低渗透油藏CO2驱油开发调整技术界限参数,并根据所得界限对不合理参数进行调整。形成一套针对大庆外围油田特低渗透油藏CO2驱油开发综合调整技术,实现CO2驱油精准开发调整目的。

CO2 flooding test in Daqing peripheral oilfields has been carried out for more than ten years. In the light of the following problems such as some non-adaptability for the current adjusting technique, severe gas channeling and poorer and uneven effects during the development process and moreover the adjusting limit parameters for the single simulation calculation are not precise enough to guide the development adjustment and other issues, six interrelated technical adjusting limits that affect the CO2 flooding effect were studied: flow pressure, gas injection pressure, gas injection velocity, formation pressure, injection-production ratio, gas-oil ratio. The typical representative Test Block S101 was selected, with the help of the combination of the mathematical calculating method and numerical simulation, the corresponding technical limit parameters were determined;through the weighted average method, the technical limit parameters were obtained for the CO2 flooding development and adjustment in the extra-low permeability oil reservoirs that meet the current status of the reservoir development, and moreover the unreasonable parameters were adjusted according to the obtained limits. A set of the comprehensive adjusting techniques were established for the CO2 flooding in the ultra-low permeability oil reservoirs in the Daqing peripheral oilfields and the purpose of precise development and adjustment of the CO2 flooding was realized.