Fu Hong, Song Kaoping, Pan Yiqi, Song Hanxuan, Meng Senyao, Liu Mingxi, Bao Runfei, Hao Hongda, Wang Longxin, Fu Xindong
Unconventional Oil and Gas Research Institute, China University of Petroleum, Beijing 102249, China.
College of New Energy and Materials, China University of Petroleum, Beijing 102249, China.
Polymers (Basel). 2024 Jan 22;16(2):299. doi: 10.3390/polym16020299.
The conventional production technique employed for low-permeability tight reservoirs exhibits limited productivity. To solve the problem, an acetate-type supercritical carbon dioxide (scCO) thickener, PVE, which contains a large number of microporous structures, was prepared using the atom transfer radical polymerization (ATRP) method. The product exhibited an ability to decrease the minimum miscibility pressure of scCO during a solubility test and demonstrated a favorable extraction efficiency in a low-permeability tight core displacement test. At 15 MPa and 70 °C, PVE-scCO at a concentration of 0.2% exhibits effective oil recovery rates of 5.61% for the 0.25 mD core and 2.65% for the 5 mD core. The result demonstrates that the incorporation of the thickener PVE can effectively mitigate gas channeling, further improve oil displacement efficiency, and inflict minimal damage to crude oil. The mechanism of thickening was analyzed through molecular simulation. The calculated trend of thickening exhibited excellent agreement with the experimental measurement rule. The simulation results demonstrate that the contact area between the polymer and CO increases in direct proportion to both the number of thickener molecules and the viscosity of the system. The study presents an effective strategy for mitigating gas channeling during scCO flooding and has a wide application prospect.
用于低渗透致密油藏的常规开采技术产能有限。为解决这一问题，采用原子转移自由基聚合（ATRP）法制备了一种具有大量微孔结构的醋酸酯型超临界二氧化碳（scCO₂）增稠剂PVE。在溶解度测试中，该产品具有降低scCO₂最小混相压力的能力，并且在低渗透致密岩心驱替试验中表现出良好的萃取效率。在15 MPa和70℃条件下，浓度为0.2%的PVE-scCO₂对渗透率为0.25 mD的岩心有效采收率为5.61%，对渗透率为5 mD的岩心有效采收率为2.65%。结果表明，增稠剂PVE的加入能有效缓解气窜，进一步提高驱油效率，且对原油的损害最小。通过分子模拟分析了增稠机理。计算得到的增稠趋势与实验测量规律吻合良好。模拟结果表明，聚合物与CO₂之间的接触面积与增稠剂分子数量和体系粘度成正比增加。该研究提出了一种在scCO₂驱油过程中缓解气窜的有效策略，具有广阔的应用前景。
