草舍油田CO2驱用气溶性发泡剂性能评价

Performance evaluation on CO2 flooding gas-soluble foaming agent in Caoshe Oilfield

为有效解决草舍油田CO2驱气窜问题,从溶解、起泡、封堵3个方面对含氟发泡剂A和含硅发泡剂B两种气溶性发泡剂进行实验评价,并优选出其中一种作为草舍油田CO2驱封窜体系。由实验结果可知,含氟发泡剂A和含硅发泡剂B在乙醇助溶剂的辅助下在超临界CO2中的溶解度分别达到2.51%和1.93%,均能达到形成稳定泡沫的溶解条件。含硅发泡剂B所产生泡沫的综合性能优于含氟发泡剂A,浓度达到1.5%时起泡性能达到最优。在高温高压(110℃、15 MPa)条件下,起泡体积达到261 mL,半衰期达到115 min。从溶解和起泡2个方面考虑,优选含硅发泡剂B作为草舍油田CO2驱泡沫封窜体系,并开展不同注入方式下的CO2泡沫封堵能力评价实验。注入方式选择CO2和发泡剂交替注入时,混合更均匀,泡沫更多,阻力因子高,可达到40以上,展现出良好的封堵性能。该封窜体系的研究为草舍油田CO2驱防气窜提供了一项新的技术支持。

In order to effectively solve the CO2 flooding gas channeling in Caoshe Oilfield,two kinds of gas-soluble foaming agents,fluorine-containing foaming agent(agent A)and silicon-containing foaming agent(agent B),are evaluated from three aspects:dissolution,foaming and plugging,and one of them is selected as the CO2 flooding sealing system in Caoshe Oilfield.The optimal injection concentration is 1.5%.According to the experimental results,the solubility of agent A and agent B in supercritical CO2 under the assistance of the co-solvent,ethanol,reach 2.51%and 1.93%respectively,and both of them can form the dissolution conditions of stable foam.The comprehensive performance of foam produced by agent B is better than that of agent A.When the concentration of agent B reaches 1.5%,the foaming performance is the best.Under the condition of high temperature(110℃)and high pressure(15 MPa),the foaming volume reaches 261 mL,and the half-life period reaches 115 min.From the aspects of dissolution and foaming,agent B is optimized as the foam sealing system of CO2 flooding in Caoshe Oilfield,and the evaluation experiments of CO2 foam sealing ability under different injection modes are carried out.When CO2 and foaming agent are injected alternately as the injection mode,the mixture is more uniform with more foam,and the resistance factor is high and can be more than 40,showing good foaming and plugging performance.The researches of sealing channeling system provide a new technical support for preventing gas channeling in CO2 flooding of Caoshe Oilfield.