Patel Hasmukh A, Santra Ashok
Drilling Technology Team, Aramco Americas: Aramco Research Center - Houston, 16300 Park Row Dr, Houston, TX, 77084, USA.
Sci Rep. 2020 Aug 17;10(1):13851. doi: 10.1038/s41598-020-70752-1.
Petroleum well drilling fluids are one of the most significant constituents in the subterranean drilling processes to meet an increasing global demand for oil and gas. Drilling fluids experience exceptional wellbore conditions, e.g. high temperature and high pressure that adversely affect the rheology of these fluids. Gas and oil well drilling operations have to adjourn due to changes in fluid rheology, since the drilling fluids may lose their effectiveness to suspend heavy particles and to carry drilled cuttings to the surface. The rheological properties of drilling fluids can be controlled by employing viscosifiers that should have exceptional stability in downhole environments. Here, we have developed next-generation viscosifiers-organically modified magnesium silicates (MSils)-for reservoir drilling fluids where organic functionalities are directly linked through the Si-C bond, unlike the industry's traditional viscosifier, organoclay, that has electrostatic linkages. The successful formation of covalently-linked hexadecyl and phenyl functionalized magnesium silicates (MSil-C16 and MSil-Ph) were confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). Identical drilling fluid formulations were designed for comparison using MSils and a commercial viscosifier. The rheological properties of fluids were measured at ambient conditions as well as at high temperatures (up to 150 °C) and high pressure (70 MPa). Owing to strong covalent linkages, drilling fluids that were formulated with MSils showed a 19.3% increase in yield point (YP) and a 31% decrease in apparent viscosity (AV) at 150 °C under 70 MPa pressure, as compared to drilling fluids that were formulated with traditional organoclay. The higher yield point and lower apparent viscosity are known to facilitate and increased drilling rate of penetration of the fluids and an enhanced equivalent circulation density (ECD), the dynamic density condition, for efficient oil and gas wells drilling procedures.
石油井钻井液是地下钻井过程中最重要的成分之一，以满足全球对石油和天然气日益增长的需求。钻井液会经历特殊的井筒条件，例如高温和高压，这些条件会对这些流体的流变学产生不利影响。由于流体流变学的变化，气井和油井的钻井作业不得不暂停，因为钻井液可能会失去悬浮重颗粒和将钻屑带到地面的有效性。钻井液的流变特性可以通过使用在井下环境中具有特殊稳定性的增稠剂来控制。在这里，我们开发了下一代增稠剂——有机改性镁硅酸盐（MSils）——用于储层钻井液，其中有机官能团通过Si-C键直接连接，这与行业传统增稠剂有机粘土不同，有机粘土具有静电连接。通过X射线衍射（XRD）、傅里叶变换红外（FTIR）光谱和热重分析（TGA）证实了共价连接的十六烷基和苯基官能化镁硅酸盐（MSil-C16和MSil-Ph）的成功形成。设计了相同的钻井液配方，以使用MSils和商业增稠剂进行比较。在环境条件以及高温（高达150°C）和高压（70MPa）下测量了流体的流变特性。由于强共价键，与用传统有机粘土配制的钻井液相比，用MSils配制的钻井液在70MPa压力下150°C时的屈服点（YP）提高了19.3%，表观粘度（AV）降低了31%。已知较高的屈服点和较低的表观粘度有利于提高流体的钻速和增强等效循环密度（ECD），即动态密度条件，以实现高效的油气井钻井程序。
