Drilling water-sensitive shale formations often leads to wellbore instability, resulting in drilling problems because of the clay's high-water affinity. To solve this problem, different nanoparticles (NPs), such as nanosilica, have been used to formulate water-based muds with potassium chloride (KCl-WBM). Nevertheless, the unmatched pore size of shale pores when using nanosilica fails to completely prevent shale swelling and dispersion. This study discusses the effects of KCl-WBM with sodium dodecyl sulphate-treated nanohydroxyapatite (nHAp/SDS) on shale swelling inhibition through various laboratory techniques. These techniques encompass the linear swell meter (LSM), the dynamic linear swell meter (DLSM), hot-rolling dispersion, suspension stability, and pore structure characterization of shale. The rheological and filtration characteristics of nHAp/SDS and compatibility tests were also studied, and the results were compared with those of nanosilica and KCl-WBM. At all concentrations, the performance of the nHAp/SDS test fluids surpassed that of nanosilica. When compared with KCl-WBM system at 10 cP and 25 °C, the nHAp/SDS and nanosilica concentrations increased the plastic viscosity by 20–90 % and 10–70 %, respectively. The inhibitory effect of nHAp/SDS surpasses that of conventional KCl-WBM and inorganic nanosilica. By adding 2.0 wt% nHAp/SDS to KCl-WBM, the shale swelling decreased from 10.1 to 4.7 % (a 53.4 % reduction). Nanosilica also reduced the swelling to 6.1 % (a 39.6 % reduction) during the LSM test at 25 °C. Under the DLSM test conditions, the shale swelling increased due to the activation of the clay platelet site at an increased temperature of 80 °C. For instance, between 25 and 80 °C, the DLSM test revealed that the shale plug height expanded from 6.1 to 9.8 % for 2.0 wt% nanosilica, 4.7–7.6 % for 2.0 wt% nHAp/SDS, and 10.1–18.8 % for KCl-WBM. Furthermore, the recovery rate of hot-rolled shale plugs with KCl-WBM increased from 89.8 to 96.2 % for nHAp/SDS and 76.6 to 88.8 % for nanosilica from the initial rates of 52.1–63.3 % between 65 and 120 °C. The contact angle results showed that nHAp/SDS is hydrophobic, reducing shale-water attraction. Moreover, the 12 nm nanosilica matches nanopore sizes to partially block shale pores. This research found that nHAp/SDS has the potential to improve wellbore stability.

中文翻译：

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十二烷基硫酸钠处理的纳米羟基磷灰石作为水基钻井液的高效页岩稳定剂

钻探对水敏感的页岩地层通常会导致井眼不稳定，从而由于粘土的高亲水性而导致钻井问题。为了解决这个问题，不同的纳米颗粒（NP），例如纳米二氧化硅，已被用来与氯化钾（KCl-WBM）配制水基泥浆。然而，使用纳米二氧化硅时页岩孔隙无与伦比的孔径无法完全阻止页岩膨胀和分散。本研究通过各种实验室技术讨论了 KCl-WBM 与十二烷基硫酸钠处理的纳米羟基磷灰石 (nHAp/SDS) 对页岩膨胀抑制的影响。这些技术包括线性膨胀计（LSM）、动态线性膨胀计（DLSM）、热轧分散、悬浮稳定性和页岩孔隙结构表征。还研究了nHAp/SDS的流变和过滤特性以及相容性测试，并将结果与​​纳米二氧化硅和KCl-WBM进行了比较。在所有浓度下，nHAp/SDS 测试液的性能均超过纳米二氧化硅。与 10 cP 和 25 °C 下的 KCl-WBM 系统相比，nHAp/SDS 和纳米二氧化硅浓度分别使塑料粘度增加了 20-90% 和 10-70%。 nHAp/SDS的抑制效果超过了传统的KCl-WBM和无机纳米二氧化硅。通过在 KCl-WBM 中添加 2.0 wt% nHAp/SDS，页岩膨胀从 10.1% 降低至 4.7%（减少 53.4%）。在 25 °C 的 LSM 测试中，纳米二氧化硅还将膨胀率降低至 6.1%（减少了 39.6%）。在 DLSM 测试条件下，在 80 °C 的高温下，由于粘土片状位点的活化，页岩膨胀增加。例如，在 25 至 80 °C 之间，DLSM 测试显示，对于 2.0 wt% 纳米二氧化硅，页岩塞高度从 6.1% 扩大到 9.8%，对于 2.0 wt% nHAp/SDS，页岩塞高度从 4.7–7.6% 扩大，对于 KCl，页岩塞高度从 10.1–18.8% 扩大-WBM。此外，在 65 至 120 °C 之间，采用 KCl-WBM 的热轧页岩塞的 nHAp/SDS 回收率从 89.8% 提高到 96.2%，纳米二氧化硅从 76.6% 提高到 88.8%，初始回收率为 52.1%~63.3%。接触角结果表明nHAp/SDS具有疏水性，降低了页岩水的吸引力。此外，12 nm 纳米二氧化硅与纳米孔径相匹配，可部分堵塞页岩孔隙。该研究发现nHAp/SDS具有提高井眼稳定性的潜力。