电性纳米材料锂皂石调控水基钻井液高温稳定性机理研究

The drilling project of deep oil and gas resources in China is generally facing high temperature problems, which puts forwards great challenges for the high temperature stability of drilling fluid during drilling process. The existing water based drilling fluid (WBM) cannot meet the needs of safety and efficiency in deep drilling. The nanomaterial laponite has unique charge characteristics and has been proven to significantly improve the temperature-resistance property of both clay and polymer, which are two key components of WBM, but its interaction mechanisms with the clay and polymer are unclear, blocking the establishment of high temperature water based drilling fluid system. The project will firstly study the effect of nano laponite on the high-temperature properties, morphological structure and charge characteristics of clay, and explore the mechanism of nano laponite to improve the high-temperature stability of clay suspension. Secondly, the synergistic effect between nano laponite and different kinds of polymers will be analyzed to determine the type and structure of the polymer with the best synergistic effect, and to find out the synergistic effect to improve the high temperature stability of the polymer. Finally, the influence of laponite on the performance of "clay-polymer" system will be studied and the interactions among "laponite, clay and polymer" will be analyzed from the microscopic point of view, revealing the mechanism of enhancing high temperature stability of water-based drilling fluids by the charged nanomaterial laponite. This project will provide theoretical and technical support for the formation of nano laponite enhanced high-temperature water based drilling fluid system.

我国深部地层油气资源钻探普遍面临高温难题，钻井液的高温稳定性面临巨大的挑战，现有水基钻井液技术不能满足深层安全高效钻井的需要。纳米材料锂皂石具有独特的带电特性，已被证实可显著提升水基钻井液造浆黏土和聚合物的抗温性，但与造浆黏土和聚合物的相互作用机制不清，阻碍了抗高温水基钻井液体系的构建。本项目拟首先研究纳米锂皂石对钻井液造浆黏土高温性能、微观构象和带电特性的影响，探明纳米锂皂石提高造浆黏土高温稳定性的机制。其次，分析纳米锂皂石与不同种类聚合物之间的协同作用效果，确定协同效果最佳的聚合物种类与结构，并探明二者协同增效提高聚合物高温稳定性的机理。最后，研究锂皂石对“造浆黏土-聚合物”体系性能的影响规律并从微观角度分析“锂皂石、造浆黏土、聚合物”三者间的相互作用，从而揭示电性纳米材料锂皂石提高水基钻井液高温稳定性的作用机理，为构建纳米锂皂石强化的抗高温水基钻井液体系提供理论与技术支撑。

我国深部地层油气资源钻探普遍面临高温难题，钻井液的高温稳定性面临巨大的挑战，现有水基钻井液技术不能满足深层安全高效钻井的需要。纳米材料锂皂石具有独特的带电特性，在钻井液领域中具有良好的应用前景。本项目首先综合评价了锂皂石的页岩抑制性能、封堵性能以及润滑性能。实验结果表明锂皂石的页岩抑制性和微纳米孔缝封堵性能良好，有利于提高钻井液的润滑和滤失性能。锂皂石在高温条件下增粘效果仍然突出，因此纳米锂皂石可以作为抗高温的无机增粘剂。其次研究了合成一种三元共聚物（聚AM/AMPS/DMDAAC），并研究了其在高温和高矿化度条件下与纳米锂皂石的作用机理。机理研究表明AAD分子结构中含有酰胺基团，磺酸基团和阳离子基团，可以和锂皂石表面形成稳定的氢键和离子键，因此锂皂石可以显著聚合物AAD的抗温性。最后，研制了一种抗高温的纳米锂皂石基降滤失剂，研究了锂皂石聚合物复合材料对钻井液性能的影响。该材料能够有效保持钻井液的粘度和滤失量，具有较好的抗温抗盐性能，可降低温高盐条件下黏土的聚结作用，有利于形成致密紧实的泥饼，显著降低钻井液的滤失量。揭示了锂皂石提高水基钻井液高温稳定性的作用机理，降滤失剂分子结构中的纳米锂皂石和聚合物长链可以与黏土颗粒相互吸附作用，增强钻井液的网络结构，增加钻井液的内摩擦力，提高钻井液的粘度；同时维持钻井液中固相颗粒的水化程度及分散性，减弱高温高盐条件下黏土的聚结作用，保持钻井液的胶体稳定性以及合理的粒度级配，形成更加致密紧实的泥饼，显著降低钻井液的滤失量。本项目为抗高温水基钻井液体系提供理论与技术借鉴。