Horizontal and multilateral wells increase continuously and are considered as a mechanical stimulation method for enhancing reservoir performance. However, drilling these wells is challenging with the conventional circulation technology because of the existence of significant pressure loss. Hence, Friction Reducers (FR) may offer a solution to this problem.

The objectives of this paper are: (1) to present the possibility of using polyacrylamide based FRs in water base drilling fluids to replace oil based drilling fluids used to drill long lateral sections; (2) to show the optimal pH values of the newly developed FR water base drilling fluids; and (3) to present the effect of FR on both drilling fluid rheological performance and shale inhibition at optimal pH values. Two commercial groups of FR were used in this study, anionic FR (AFR) and cationic FR (CFR). Lab experiments were conducted initially to obtain the effect of pH on the FRs with water and with bentonite by using a low pressure and high temperature rheometer and a Zeta potential analyzer. The rheological properties of formulated Water Based Fluid (WBF) with and without anionic FRs were measured at temperatures ranging from 120° F to 180° F. The zeta potential was also measured to investigate the capability of using anionic FRs as shale inhibition in WBF.

The experimental results reveal that the isoelectric point of CFR is at pH value of 8.5 and this CFR charges negatively above pH 8.5. With increasing pH, the viscosity of CFR decreases and there is rise in shear stress of bentonite with CFR. There are obvious effects of pH on anionic FRs with bentonite due to the attraction of negative carboxylate group on AFR surface to positive edge of bentonite. This attraction is a good indicator that anionic FRs can be used as shale inhibition. The optimal pH of using AFR with WBF is from 8.5 to 9.5 for better WBF system stability. The results also reveal that AFR supports thermal stability of the formulated KCl polymer WBF. Furthermore, the formulated WBF with AFR minimize formation damage due to having lower API and high pressure and high temperature filter loss. Zeta potential measurements indicates the initial concentration of AFR used in WBF without KCl for shale stabilization is 18 pptg (0.72 lbm/bbl).

This study introduces a promising alternative WBF which could be used to replace oil based drilling fluids when drilling long lateral sections. This proposed approach is important for the oil and gas industry not only for cost effectiveness but also to avail environmental concerns.

水平井和分支井不断增加，被认为是提高储层性能的机械增产方法。然而，由于存在显着的压力损失，使用传统的循环技术钻这些井具有挑战性。因此，减摩器 (FR) 可以解决这个问题。

本文的目的是： (1) 提出在水基钻井液中使用聚丙烯酰胺基阻燃剂替代用于钻长侧段的油基钻井液的可能性；(2) 展示新开发的FR水基钻井液的最佳pH值；(3) 展示了在最佳 pH 值下 FR 对钻井液流变性能和页岩抑制的影响。本研究中使用了两种商业阻燃剂组，阴离子阻燃剂 (AFR) 和阳离子阻燃剂 (CFR)。通过使用低压和高温流变仪和 Zeta 电位分析仪，最初进行了实验室实验，以获得 pH 值对水和膨润土 FR 的影响。在 120° F 至 180° F 的温度范围内测量了含有和不含阴离子 FR 的配制水基流体 (WBF) 的流变特性。

实验结果表明，CFR的等电点在pH值为8.5时，该CFR在pH 8.5以上时带负电。随着 pH 值的增加，CFR 的粘度降低，CFR 膨润土的剪切应力增加。由于 AFR 表面的负羧酸根基团吸引到膨润土的正边缘，因此 pH 值对带有膨润土的阴离子 FR 有明显的影响。这种吸引力是一个很好的指标，表明阴离子 FR 可以用作页岩抑制剂。将 AFR 与 WBF 一起使用的最佳 pH 值为 8.5 至 9.5，以获得更好的 WBF 系统稳定性。结果还表明，AFR 支持配制的 KCl 聚合物 WBF 的热稳定性。此外，配制的具有 AFR 的 WBF 由于具有较低的 API 和高压和高温过滤器损失，可最大限度地减少地层损害。

本研究介绍了一种有前景的替代 WBF，可用于在钻长横向段时替代油基钻井液。这种提议的方法对石油和天然气行业很重要，不仅对成本效益，而且对环境问题也有帮助。