棉短绒水凝胶油田堵剂的制备与性能评价

Preparation and Evaluation of Cotton Staple Hydrogel Plugging Agent

何垒垒 闫芳宁 何 龙 黄雪莉

HE Leilei YAN Fangning HE Long HUANG Xueli

为提高注水油田的采收率，拓展棉短绒等生物质材料在石油开采领域中的应用，本文以棉短绒为原料，通过盐酸预处理、在6% NaOH+4%尿素溶液中冷冻溶解、与环氧氯丙烷反应等过程，制备出棉短绒水凝胶堵剂。采用热重仪、静态力学测试仪、流变仪、采油化学剂评价仪等对其性能进行测试评价。研究结果表明：棉短绒预处理的适宜条件为棉短绒质量3 g，质量分数3%的稀盐酸36 mL，加热温度95℃、加热时间为120 min；水凝胶的合成条件为反应温度60℃，成胶时间5 h，棉短绒质量3 g，交联剂4 mL，6% NaOH+4%尿素溶液40 mL。在此条件下合成的水凝胶的预聚体的黏度低，易泵注；凝胶堵剂对初始渗透率为 257.23×10-3 μm2的岩心的封堵率达到99.64%，抗压强度达到131 kPa。棉短绒水凝胶具有较好的耐温耐盐性且成本较低。

In order to enhance oil recovery of water flooding oilfield and extend utilization of green raw materials such as cotton staple in oil exploitation，the hydrogel plugging agent was synthesized from cotton staple through preprocessing by hydrochloric acid freezing and resolving in 6% NaOH +4% urea mixed solution，and reacting with epichlorohydrin. The performance of the hydrogel plugging agent was evaluated by thermogravimetry，static mechanical tester，rheometer and oil production chemical evaluation instrument. The optimum conditions for preprocessing cotton staple were cotton staple 3 g，dilute hydrochloric acid 36 mL with mass fraction 3%，temperature 95℃ and heating time 120 min. The synthetic conditions of hydrogel plugging agent were as follows：reaction temperature 60℃，gelling time 5 h，cotton staple 3 g，crosslinking agent of epichlorohydrin 4 mL，6% NaOH+ 4% urea mixed solution 40 mL. The prepolymer synthesized under these conditions had low viscosity，and could be pumped into oil well easily. The plugging rate of the hydrogel could achieve up to 99.64%，the compressive strength was of 131 kPa. The cotton staple hydrogel plugging agent possessed better temperature and salt resistance and low cost.