高温地层钻井堵漏材料特性实验

深井高温地层堵漏技术对堵漏材料的抗/耐温能力、抗压强度和沉降稳定性等提出了更高要求。针对高温地层钻井堵漏技术难题，基于220℃高温老化质量损失率、粒度降级率、抗压破碎率、抗压弹性变形率、摩擦系数变化率、纤维断裂强度保持率等技术指标，借助扫描电镜观察堵漏材料高温老化前后微观结构变化，评价了常用的有机植物类、有机聚合物类和无机矿物类堵漏材料的基本抗温能力，揭示了高温老化性能下降机理。利用自制的高温高压裂缝封堵模拟实验装置，探讨了高温封堵层失稳破坏机制。实验优选出抗220℃高温的微细填充颗粒、弹性变形颗粒和片状填塞颗粒等3种堵漏材料；基于耐热高分子和无机矿物材料，自制了抗高温高强度低密度的刚性架桥颗粒、抗高温高强度纤维类两种新型堵漏材料。基于强力链网络结构的致密承压封堵基本原理，通过不同类型抗高温堵漏材料的复合协同作用，优化得到了针对不同裂缝开度的抗高温致密承压封堵工作液配方，其承压能力≥ 10 MPa，沉降稳定性好，酸溶率高，可用于解决高温地层或储层钻井堵漏技术难题。

Experiment on properties of lost circulation materials in high temperature formation

The plugging technology for deep-well high temperature formation has high requirements on temperature resistance, compressive strength and settlement stability of the lost circulation materials (LCMs). This article was focused on the technical problems of curing losses in high temperature formation. This study established the experimental method to evaluate temperature resistance of LCMs, such as organic plant, organic polymer and inorganic mineral. The evaluation parameters including mass loss rate, size degradation rate, crushing rate, resiliency deformation rate, friction coefficient and breaking strength retention rate. Scanning electron microscope was used to observe the microstructure of LCMs before and after high temperature aging. The mechanism of poor performance of LCMs after high temperature aging was proposed. A fracture sealing testing apparatus was proposed to carry out sealing experiment at high temperature and high pressure. Instability mechanism of sealing zone caused by high temperature aging was investigated. Three kinds of LCMs, such as fine filling particles, elastically deformed particles and flaky materials were selected which could resist 220℃. Based on heat-resistant polymer and inorganic mineral materials, two types of novel high-temperature resistant LCMs were prepared, i.e., the rigid bridge particles with high compressive strength and low density, and high strength fiber. Based on the basic principle of tight sealing with high sealing pressure of strong-chain network structure. Different kinds of high-temperature resistant LCMs were synergized to seal fracture. High-temperature resistant LCM formulas were optimized for tapered slot with different entrance width. The sealing pressure was more than 10 MPa. The LCM formulas had good suspension capacity and high acid solubility. It could solve the lost circulation problem in high temperature deep well or reservoir.