Abstract: This paper investigated the suitability of xanthan gum as a thixotropic agent utilized in high-temperature natural gas well cementation. The konjac gum and KCl are used to synthesize a novel thixotropic agent and keep the thixotropic property of xanthan gum at high temperatures. The increment of consistency method are used to evaluate the thixotropic performance of the cement. Compressive strength tests, scanning electron microscope, and X-ray diffraction analysis are performed to study the effects of the thixotropic agent on the properties of cement at high temperatures. Moreover, the thixotropic mechanism is revealed, as well. Test results show that the high-temperature resistance property of xanthan gum is limited. The konjac gum and KCl should be used to enhance the thermal stability of xanthan gum to achieve better thixotropic property at high temperatures. The thixotropic agent does not influence the hydration products but slows down the hydration process of cement. Even though the thixotropic agent influences the microstructure of cement, the compressive strength still meets the sealing requirements of natural gas wells. The K+ ions in KCl connect the molecular chains in xanthan gum through the salt bridge effect, which inhibits the transformation of xanthan gum's double helix structure and enhances the thermal stability of the molecular structure. Furthermore, the acetyl groups in konjac gum generate hydrogen bonds with pyruvate groups in xanthan gum. This effect makes the composite structure more stable and finally results in a thermal stable thixotropic agent. The proposed novel three components thixotropic agent is an effective solution to solve the gas migration issue in high-temperature natural gas wells.

中文翻译：

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一种提高天然气井水泥高温触变性能的三组分触变剂

摘要：本文研究了黄原胶作为触变剂在高温天然气固井中的适用性。魔芋胶和氯化钾用于合成一种新型触变剂，在高温下保持黄原胶的触变性。稠度增量法用于评价水泥的触变性能。进行抗压强度测试、扫描电子显微镜和 X 射线衍射分析，以研究触变剂对高温下水泥性能的影响。此外，还揭示了触变机制。试验结果表明，黄原胶的耐高温性能是有限的。应使用魔芋胶和KCl来增强黄原胶的热稳定性，以达到更好的高温触变性。触变剂不会影响水化产物，但会减慢水泥的水化过程。尽管触变剂影响了水泥的微观结构，但其抗压强度仍满足天然气井的密封要求。KCl中的K+离子通过盐桥效应将黄原胶中的分子链连接起来，抑制了黄原胶双螺旋结构的转变，增强了分子结构的热稳定性。此外，魔芋胶中的乙酰基与黄原胶中的丙酮酸基产生氢键。这种效果使复合结构更稳定，最终产生热稳定的触变剂。所提出的新型三组分触变剂是解决高温天然气井中气体运移问题的有效解决方案。