摘要
针对低渗透裂缝型油藏堵水施工过程中堵水剂易沿裂缝向地层漏失这一问题，提出了复合堵水剂的堵水工艺。选定聚酰胺-胺树枝聚合物/有机酚醛交联体系进行配方优选，并研究与复配的预交联颗粒的性能。实验结果表明，由2000 mg/L聚合物、1500 mg/L乌洛托品、250 mg/L间苯二酚、1600 mg/L 乙二酸、180 mg/L硫脲、200mg/L氯化钴组成的凝胶体系的成胶强度为21600 mPa·s，稳定时间为103 d，与其复配的预交联颗粒在地层水中的膨胀倍数为15.7，且具有较好的抗盐性。0.3 PV（0.05 PV浓度为2000 mg/L的预交联颗粒、0.2 PV浓度为2000 mg/L的聚合物凝胶体系和0.05 PV浓度4000 mg/L的聚合物凝胶体系）的复合堵水剂对人工造缝岩心的封堵率高达97.25%以上，突破压力梯度最高达13.68 MPa/m，并且具有较好的调整产液剖面的能力。现场施工后施工井综合含水率下降了10.5%，取得了较好的堵水效果。
Abstract
In view of the problem that plugging agent leaks easily along the crack formation during water plugging construction at the low permeable fractured reservoir, the compound plugging agent technology was put forward. The polyamidoamine dendrimers /organic phenolic aldehyde crosslinking system were selected, and the performance of the pre-crosslinked particlesc was studied. The results showed that, the strength of gel system, consisted of 2000 mg/L polymer, 1500 mg/L hexamine, 250 mg/L resorcinol, 1600 mg/L oxalic acid, 180 mg/L thiourea and 200 mg/L cobalt dichloride, was up to 21600 mPa?s and the settling time was of 103 days. The expansion rate of the pre-crosslinked particles reached 15.7 times in the formation water, performing good salt tolerance. 0.3 PV composite plugging agent, composed of 0.05 PV pre-crosslinked particles with the concentration of 2000 mg/L, 0.2 PV polymer gel system with the concentration of 2000 mg/L and 0.05 PV polymer gel system with the concentration of 4000 mg/L, was injected into artificial cracked core, the plugging rate being of above 97.25%, breakthrough pressure gradient being up to 13.68MPa/m, indicating that the composite plugging agent had a good ability to adjust production profile. After the site construction, the total water content of construction well decreased by 10.5%, and good water plugging effect was obtained.
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