李 锟¹，张春梅¹，刘 成²，梅开元¹，胡 陈¹，程小伟¹

（1. 西南石油大学 新能源与材料学院，油气藏地质及开发工程全国重点实验室，四川 成都 610500；2. 中国石油西南油气田公司勘探事业部，四川 成都 610000）

引用格式：

李锟，张春梅，刘成，等 .基于硅酸钠和硅藻土的油井水泥自愈合材料的制备及表征［J］. 中国粉体技术，2024，30（3）：64-75.

Li Kun， Zhang Chunmei， Liu Cheng， et al. Preparation and characterization of oil well cement self-healing materials based on sodium silicate and diatomite［J］. China Powder Science and Technology，2024，30（3）：64−75.

DOI：10.13732/j.issn.1008-5548.2024.03.006

收稿日期：2023-09-28，修回日期：2023-11-28，上线日期：2024-04-15。

基金项目：国家自然科学基金项目，编号：42207206；文昌 9-7 油田多分支复杂结构井固井方案及工作液体系研究项目，编号：CCL2022RCPS0702PSN。

第一作者简介：李锟（1999—），男，硕士生，研究方向为固井自愈合材料。E-mail：1194074067@qq. com。

通信作者简介：

张春梅（1977—），女，副教授，硕士生导师，研究方向为固井新材料研发。E-mail：200531010045@swpu. edu. cn。

程小伟（1977—），男，教授，博士，四川省学术和技术带头人，博士生导师，研究方向为先进胶凝材料及其在固井中应用。E-mail： chengxw@swpu. edu. cn。

摘要：【目的】研究硅藻土对硅酸钠的吸附效果，探讨油井水泥环微裂缝的修复问题。【方法】 采用硅酸钠作为自愈合剂，硅藻土为载体，利用真空浸渍法制备硅藻土基自愈合材料；借助扫描电子显微镜（scanning electron microscope ，SEM）、红外光谱仪（infrared spectrometer，FTIR）、全自动表面积和孔结构分析仪（automatic surface area and pore structure analyzer，BET）进行分析；通过对比分析掺入硅藻土基自愈合材料前、后水泥石的抗压强度、恢复率和渗透率等，对自愈合效果进行评价；通过对水泥石裂缝表面物质进行X射线衍射分析（X-ray diffraction，XRD）、热重分析（thermal analysis，TG）和SEM分析材料的自愈合机制。【结果】 利用真空浸渍法能够成功制得硅藻土基自愈合材料；硅藻土基自愈合材料在油井水泥中最佳掺量为9%（质量分数），该试样劈裂造缝后自愈合14 d的抗压强度比纯水泥的提高99. 57%，自愈合14 d后渗透率为0. 42 mD，渗透率降低率达到75. 44%，比纯水泥试样的高40. 94%，且自愈合14 d后裂缝表面已经闭合。【结论】 硅藻土基自愈合材料制备工艺简单，在油井水泥浆中具有良好的分散性和稳定性，可以促进油井水泥石微裂缝自愈合。

Objective The expansion of micro-cracks in oil well cement will seriously affect the safe exploitation of oil and gas. Self-healing cement slurry has the advantage of timely response to repair micro-cracks. When micro-cracks are generated， the self-healing agent is triggered to repair micro-cracks in time. As a potential self-healing agent in cement-based materials， sodium silicate can react with calcium hydroxide （Calcium hydroxide， CH） to form hydrated calcium silicate （Calcium-silicate-hydrate，C-S-H）. Microcapsule technology is usually used to encapsulate sodium silicate. However， the compatibility between microcapsules and cement paste is poor. To overcome this problem， this paper aims to use inorganic porous mineral diatomite with rich pore structure and excellent physical and chemical properties to adsorb sodium silicate to prepare diatomite-based self-healing materials and to explore its effect on the self-healing properties of oil well cement.

Methods Diatomite-based self-healing materials were prepared using the vacuum impregnation method. The diatomite-based self-healing materials were characterized by scanning electron microscope （SEM）， infrared spectrometer （FTIR）， and automatic surface area and pore structure analyzer （BET）. The self-healing effect was evaluated by comparing and analyzing cement stone's compressive strength， recovery rate and permeability before and after incorporation of diatomite-based self-healing materials. The self-healing mechanism of diatomite-based self-healing materials was analyzed by X-ray diffraction analysis （XRD），thermal analysis （TG） and SEM.

Results and Discussion It was found that the number of pores on the sample surface after adsorption was significantly reduced compared with that before adsorption， and most of the pores were filled. BET analysis also showed that the pore volume and average pore size after adsorption were smaller than before adsorption. Combined with FTIR analysis， it was confirmed that the adsorption material in the pores of diatomite was sodium silicate. Then， diatomite-based self-healing materials were added to cement at different mass fractions of 0%，3%，6%，9%， and 12%. The 14 d compressive strength of the sample with 9% content was （39. 56±1. 98） MPa， which was 17. 95% higher than that of the pure cement sample. At the same time， the self-healing experiment of cement stone after the Brazilian splitting method was carried out. The compressive strength of the sample with 9% content reached （36. 90±1. 85） MPa after 14 d of self-healing， which was 99. 57% higher than that of the pure cement sample after 14 d of self-healing. The permeability of the sample with 9% content was 0. 42 mD after 14 d of self-healing， and the permeability reduction rate was 75. 44%， which was 40. 94% higher than that of the pure cement sample. The XRD test analysis of the material at the crack surface of the sample showed that the content of CH in the material at the crack surface of the diatomite-based self-healing material was lower than that of pure cement. The results of TG analysis showed that the CH content in the crack surface of the diatomite-based self-healing material was lower than that of the pure cement sample， and the C-S-H content was higher than that of the pure cement sample. Combined with SEM analysis， it was confirmed that the self-healing product of diatomite-based self-healing material at the crack of cement stone was C-S-H.

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