油包水型乳化压裂液的研制与性能评价

发布时间：2018-03-24 17:07

  本文选题：压裂　切入点：油包水乳状液　出处：《东北石油大学》2017年硕士论文

【摘要】：压裂改造作为低渗透油藏最有效的开发方式,能够保证其应有的采油速度,进而提高采收率,推进低渗储量的动用。针对低渗油藏储层物性差、渗透率低、水敏性强等特点,本文合成了油包水型乳化压裂液体系,改善了常规压裂液对地层损害严重、成本高的缺陷,使其在低渗、强水敏储层中有较好的适用性。本文以五氧化二磷、磷酸三乙酯、有机醇为原料合成了稠化剂烷基磷酸酯,利用双指示剂滴定法对其产率进行了测定,通过正交试验法分析了反应时间、反应温度、反应物投料比对产率的影响,结合基液配伍性实验,确定了稠化剂的最佳合成条件为:(1)聚合时间5h、聚合温度85℃、P2O5与C6H15O4P摩尔投料比1:1.5,(2)酯化时间5.5h、酯化温度100℃、单烷基磷酸酯中间体与混合醇摩尔投料比为1:1.4,混合醇组合为正丁醇、正辛醇、十六醇,三者摩尔比为1:1:1;对稠化剂DC-1进行了红外光谱表征,结果显示合成物中含有磷酸酯构架,为预期产物。确定了复合交联剂DZ-1的配方为:25wt%硫酸铁+8%wt乙二醇+12wt%柠檬酸三钠+水。通过实验分析了乳化剂种类及加量、油水体积比、反应温度对油包水乳化压裂液稳定性的影响,确定了复配乳化剂的配方为:90%Span80+5%Tween80+5%月桂醇,得到最佳稳定条件为:复配乳化剂加量2%、油水体积比6:4、温度70℃;采用上述配方合成了油包水乳化压裂液体系,结果表明该体系成胶性能较好,在温度25℃、剪切速率170s-1条件下,表观黏度可达329.8m Pa.s。对油包水乳化压裂液体系进行了性能评价,确定了最佳交联比与稠化剂使用浓度分别为1:1.25与1.5%;该配方下交联后的油包水乳化压裂液体系在70℃,170s-1下剪切45min以上后,压裂液黏度仍保持在155m Pa.s左右,具有较好的耐温耐剪切性能,适用于70℃以下的储层压裂改造;应变扫描结果显示,该压裂液体系弹性模量1.0Pa,耗能模量0.3Pa,呈胶体特性;经实验测定,该压裂液体系具有较好的悬砂性能,石英砂在其沉降速率为0.0025mm/s,且当破胶剂加量为2%,破乳剂加量为0.8%时,破胶破乳后压裂液的黏度为4.74m Pa.s,符合压裂液通用标准中的返排黏度要求。
[Abstract]:As the most effective development method of low permeability reservoir, fracturing can guarantee the oil recovery rate, and then improve the recovery factor, promote the production of low permeability reserves, aiming at the poor physical property, low permeability and strong water sensitivity of low permeability reservoir, etc. In this paper, the oil-in-water emulsion fracturing fluid system is synthesized, which improves the defects of the conventional fracturing fluid which has serious damage to formation and high cost, and makes it suitable for low permeability and strong water sensitive reservoir. The thickener alkyl phosphate was synthesized from organic alcohol and its yield was determined by double indicator titration. The effects of reaction time, reaction temperature and feed ratio of reactants on the yield were analyzed by orthogonal test. In combination with the compatibility experiment of base solution, the optimum conditions for the synthesis of thickener were determined as follows: polymerization time 5 h, polymerization temperature 85 鈩，

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