纳米石蜡乳液封堵材料的合成与性能评价

Synthesis and Evaluation of a Nanophase Wax Emulsion Plugging Material

采用乳状液转换点法(EIP法)和乳化剂在油中法相结合,以Span80、Tween80为复合乳化剂,并加入乳化助剂疏水缔合羟乙基纤维素(HMHEC)制备出性能稳定的纳米石蜡乳液。其中,复合乳化剂的HLB值为10.5,浓度为11%,乳化助剂HMHEC浓度为0.6%,纳米乳化石蜡乳液平均粒径在65 nm。制备的纳米石蜡乳液稳定性良好,静置24 h的纳米石蜡乳液沉降稳定性良好,24 h的沉降率在5%左右。与常用钻井液处理剂的配伍性实验结果表明,抑制剂NH4-HPAN和增黏剂XC会使纳米石蜡乳液粒径增大,超过100 nm;纳米石蜡乳液与其他钻井液处理剂的配伍性良好。封堵实验结果表明,纳米石蜡乳液对页岩级泥饼孔隙具有良好的封堵能力,封堵率可以达到92.59%,封堵效果优于无机纳米封堵材料氧化锌和碳酸钙。

A stable nanophase wax emulsion has been developed using emulsion inversion point（EIP） method combined with emulsifierin-oil method, with Span 80 and Tween 80 as compound emulsifier and hydrophobically modified hydroxyethyl cellulose（HMHEC） as emulsion additive. The compound emulsifier has an HLB value of 10.5. The concentration of the compound emulsifier in the reaction raw materials was 11%, and the concentration of HMHEC 0.6%. The average particle size of the nanophase wax emulsion is 65 nm. The produced nanophase was emulsion had good stability, with 24 h rate of sedimentation of about 5%. Test on the compatibility of the nanophase wax emulsion with commonly used mud additives shows that apart from NH4-HPAN and XC, which will increase the particle sizes of the emulsion to over 100 nm, other commonly used mud additives are well compatible with the nanophase wax emulsion. Plugging test results show that the nanophase wax emulsion effectively plugs the pore spaces in shale mud cakes, with 92.95% of the pore spaces being plugged, a plugging efficiency that is better than that of inorganic nanophase plugging agents such as zinc oxide and calcium carbonate.