离子液体对钻井液性能的影响及其作用机理研究

The effective regulation of rheology and control on filtration loss under high temperature is one of the major technical problems for water-based drilling fluid in deep drilling. Generally, anti-temperature filtrate loss control agents and anti-temperature thinner are added in order to increase the colloidal stability of drilling fluid under high temperature. However, it will inevitably cause the clay mineral more dispersion and the well instability. Meanwhile, the clay in drilling fluid will be dispersed further at high temperature. Inhibitor should be added to overcome these difficulties. But the common inhibitor would increase the filtration loss. Our recent research has shown that ionic liquid can greatly inhibit clay dispersing and control the filtration loss. Ionic liquids have great potentional application in many fields, due to their designable structure, "zero" vapor pressure, high-temperature resistance and so on. Therefore this maybe break through the technical bottle neck. We will further study the effect of ionic liquid, the research includes the following three parts: Firstly，the influence of ionic liquid on the properties of drilling fluid will be fully studied, including the inhibition, filtration loss and rheology, and the relationship between the structure of ionic liquid and performance of drilling fluid will be studied in detail. Then functional ionic liquid will be synthesized according to special usage on the base of the former study. At last through experiments the mechanism which the ionic liquid have action on clay will be explored. This study aims to explore the relationship between the properties of drilling fluid and ionic liquid, and solve the contradiction between inhibition and stability of drilling fluid under high temperature.

流变性不稳定和滤失量大是目前深部钻探高温水基钻井液仍未解决的重大技术难题。通常采用抗高温降滤失剂和抗高温稀释剂来保持钻井液的高温胶体稳定性。但是这样会引起地层粘土矿物更加分散，井壁不稳定；同时高温下钻井液中粘土也更加分散。加入常用的抑制剂又会加大滤失量、使流变性不稳定。申请者近期研究发现某些离子液体在高温下能很好的抑制粘土水化分散，且有一定的降滤失作用。离子液体具有结构可设计性、"零"蒸汽压、热稳定性高等独特优点，使其有望突破这一技术瓶颈。本项目将进一步开展不同结构的离子液体对钻井液抑制性、滤失性、流变性等性能影响的研究，探索离子液体结构与钻井液性能的关系；在此基础上根据特定应用需要设计合成功能化的离子液体；最后研究离子液体与粘土矿物的作用机理。本项目意在能对离子液体对钻井液性能的影响进行更为深入的探索，探明其作用机理，解决高温下钻井液抑制性和稳定性的矛盾。

深部钻井的成功很大程度上取决于钻井液的抗高温性能。目前抗高温水基钻井液的处理剂都是水溶性的天然和合成聚合物。这些聚合物一般都在200℃以下分解。因此流变性不稳定和滤失量变大仍然是抗高温水基钻井液存在的关键问题。离子液体具有优异的热稳定性等独特性能，在很多方面都展示了广阔的应用潜力和传统方法不可比拟的优势。由于具有优异的热稳定性，本项目开展了咪唑类的离子液体对钻井液热稳定性的影响。主要研究内容和结果如下：.（1） 研究了不同浓度咪唑类离子液体（TILA）对钻井液高温流变性的影响；.采用ZNN-D6旋转粘度计和 FANN 50SL高温流变仪两种不同的测试仪器研究了不同浓度TILA高温对钻井液流变性的影响。高温滚动实验表明：120°C和160°C滚动16h后， 未加入TILA基浆的切力和动塑比降为零；而加入0.05%（质量含量）TILA，提高了钻井液的动切力，降低钻井液的塑性粘度，从而提高了钻井液的动塑比。用FANN 50SL研究结果表明加入低浓度（0.1质量%以下）的TILA可以提高4%膨润土含量钻井液的粘度， 说明TILA可以提高钻井液的抗温性，甚至可以抗温高达240°C。同时高温下粘土入侵时，钻井液粘度变稠时加入TILA又可以降低钻井液体系的粘度。两种测试方法都表明加入低浓度的TILA可以提高和调节钻井液的高温流变性，钻井液体系可以容纳更多的固相。 .（2）研究了不同浓度咪唑类离子液体TILA对钻井液高温滤失量性的影响；. 加入低浓度的TILA才能降低淡水基浆和聚合物基浆的API滤失量，降低的幅度不大；TILA不能降低淡水基浆的HTHP滤失量， 0.05%TILA可以降低PMA聚合物基HTHP滤失量。.（3）研究了咪唑类离子液体TILA对钻井液抑制性的影响；.通过页岩滚动回收率实验、CST值测试、粒度及Zeta电位测定和抑制膨润土造浆实验四种实验方法研究了TILA对钻井液抑制性的影响，并以常用抑制剂KCl 和聚胺作对比，结果表明浓度为0.05%TILA抑制性与1%的聚胺相当，但抑制性要优于5%KCl；.（4）咪唑类离子液体TILA与粘土作用机理研究。.研究TILA在钠蒙脱石粘土矿物中的吸附行为。分别研究了反应时间、溶液浓度、pH值对其吸附行为产生的影响；采用XRD、FITR、TG和SEM测试手段分析和研究了咪唑类阳离子在蒙脱石层间的吸附态。