注CO₂吞吐微观机理可视化实验

Visualization experiment on micro mechanism of CO₂ huff and puff

刘建仪 2 李牧² 刘洋² 周浩²

西南石油大学油气藏地质及开发工程国家重点实验室，四川 成都 610500 西南石油大学石油与天然气工程学院，四川 成都 610500

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China School of Oil and Natural Gas Engineering, Southwest Petroleum University, Chengdu 610500, China

针对高温高压下注CO₂吞吐微观动态过程和微观作用机理认识不清的问题，自主研发了一套高温高压微观可视化实验装置，实现了高温高压条件下CO₂吞吐微观动态过程的实时观测。实验研究表明：注气过程中，CO₂具有顺势而流的现象，与水驱过程相同，在速度梯度作用下会优先进入大通道；焖井过程中，速度势转变为浓度势，CO₂在浓度梯度作用下扩散进入小孔道和盲孔，溶解到其中的原油中，使原油进入优势大通道；回采过程中，压力逐渐降低，浓度势转变为压力势，CO₂在压力梯度的作用下带动大通道中的原油采出；大通道流动能力越强，CO₂波及距离越远，接触的小孔道越多，扩散波及到的面积越大，采出的油越多。该研究明确了CO₂吞吐的微观作用机理，为现场优选吞吐时机、改进吞吐措施提供了理论指导。

In order to clarify the microscopic dynamic process and mechanism of CO₂ under high temperature and high pressure, a set of visualization experiment device was developed, which realized the real-time observation of the dynamic process of CO₂ under high temperature and high pressure. Microscopic visualization experimental study shows that CO₂ will be the first to enter the large channel under the driving of the velocity potential in the process of gas injection. In soaking process, CO₂ diffuses into the hole and dissolves in the crude oil in small hole and blind hole and expands into large pores. In the extraction process, with the reducing pressure, the concentration potential is changed into the pressure potential, and the CO₂ is driven by the crude oil in the channel. if the flow capacity of the large channel becomes lager, CO₂ will spread over a larger scale of area and more oil will be produced because of more exposed channel. The study makes clear the microscopic mechanism of CO₂, and provides theoretical guidance for the field application of CO2 huff and puff.

10.6056/dkyqt201702020