新型屏蔽暂堵剂ZDJ室内性能评价

针对传统保护油气层技术和弹性体屏蔽剂的不足,合成了一种具有壳核结构的新型屏蔽暂堵剂ZDJ,该屏蔽暂堵剂利用其可变形特点嵌入孔喉表面,起到保护油气层作用,不需要其粒径与地层孔喉直径及分布准确匹配。新型屏蔽暂堵剂由一定量的AM、AMPS、DMC、N,N-亚甲基双丙烯酰胺和无机试剂A,通过自由基聚合法合成,中间黑色部分为刚性核,边缘透明部分为弹性体。其性能评价结果表明,当无机试剂A质量分数为50%时,ZDJ封堵性能最佳;0.5% ZDJ的砂层侵入深度为2.3~5.9 cm,API滤失量为8.5 mL;将ZDJ、磺化沥青和LV-CMC进行复配,当3者比例为4.5:1.5:1.0时,钻井液封堵性和降滤失性达到最佳,1.0%复配体系的砂层侵入深度为0.6~2.7 cm,API滤失量为6.1mL,200×10-3~300×10-3 μm2人造岩心渗透率暂堵率为99.2%,渗透率恢复率为99.3%;说明ZDJ、磺化沥青和LV-CMC具有较好的协同增效作用,能有效阻止钻井液流体和固相颗粒侵入油气储层孔隙,到达保护油气储层目的。 

Laboratory Evaluation of a New Temporary Plugging Agent ZDJ

A new temporary plugging agent, ZDJ, was produced to overcome the deficiencies of conventional reservoir protection technology and elastic sealing agents. ZDJ has a core-shell structure, and good deformability enabling it to be adhered on to the interior surface of pore throats, thus protecting reservoir from being damaged. This technology does not necessitate the accurate compatibility of additive's particle sizes with diameters of pore throats. ZDJ is produced with AM, AMPS, DMC, N, N'-Methylene bis-acrylamide and an inorganic agent A, using radical polymerization.The black part at the center is a rigid core, and the transparent part at the brim is an elastic mass. The evaluation indicates that ZDJ shows the optimum plugging performance at 50% (mass fraction) of A. Sand beds plugged with 0.5% ZDJ have fluid invasion depths of 2.3-5.9 cm, and API filter loss of 8.5 mL. When ZDJ, sulfonated asphaltene and LV-CMC are compounded at a ratio of 4.5:1.5:1.0, the best plugging and filtration control performances can be achieved. Sand beds plugged with 1.0% of the compound have fluid invasion depths of 0.6-2.7 cm, and filter loss of 6.1 mL. In tests on artificial sand cores having permeabilities of 200×10-3-300×10-3 μm2,99.2% of pores are plugged with the compound, and permeability recovery reaches 99.3%, indicating that ZDJ, sulfonate asphaltene and LV-CMC have good synergistic effect in hindering the invasion of mud filtrates and solids, thus realizing the protection of oil and gas reservoirs.