Sun Yuxue, Zhu Xiuyu, Zhao Jingyuan, Sui Dianjie
College of Petroleum Engineering, Northeast Petroleum University, Daqing, China.
Drilling Engineering Technology Research Institute, Daqing Drilling Engineering Company, Daqing, China.
Front Chem. 2020 Dec 14;8:539690. doi: 10.3389/fchem.2020.539690. eCollection 2020.
In view of the pollution problems related to using oil-based drilling fluids, we prepared a new environmentally friendly synthetic fluid, namely, NSF, for use in synthetic-based drilling fluid instead. We used heavy hydrocarbons from Daqing as raw material in our preparation and employed few-steps refining techniques, such as hydrodesulfurization, hydrodearomatization, and hydrogenation. After the treatment, the sulfur and aromatic hydrocarbon contents in the NSF were <0.5 mg/L, meeting international environmental standards. NSF is composed mainly of C-C hydrocarbons, and is characterized by low impurity content, small specific gravity, and easy degradation. In addition, the LC50 value is >1,000,000 mg/L water-soluble fraction; therefore, its toxicity is <10% of that of diesel in oil-based drilling fluid and, as the flash point of NSF is about 134°C, the related fire hazard is low. The synthetic-based drilling fluid with NSF has the advantage of causing no swelling damage to the reservoir, and saves the cost of drilling fluid because it doesn't need to deal with the environmental problems (the sulfur and aromatic hydrocarbon contents were <0.5 mg/L) and field problems caused by the reaction between drilling fluid and reservoir, and greatly increases the ROP through reducing the drill pipe sticking and with C-C hydrocarbons in synthetic-based fluid, and safely uses, and has stable drilling fluid performances which are flash point (134°C) and low fire hazard. We have therefore achieved our aim of preparing a high-quality and non-toxic synthetic fluid, of which the aromatic hydrocarbon and sulfur contents meet international standards. Using this synthetic-based drilling fluid therefore facilitates environment protection drilling.
鉴于使用油基钻井液所带来的污染问题，我们制备了一种新型环保合成液，即NSF，用于替代合成基钻井液中的油基钻井液。我们以大庆的重质烃为原料进行制备，并采用了几步精炼技术，如加氢脱硫、加氢脱芳和氢化。处理后，NSF中的硫和芳烃含量<0.5mg/L，符合国际环境标准。NSF主要由碳-碳烃组成，具有杂质含量低、比重小、易降解的特点。此外，其LC50值>1,000,000mg/L水溶部分；因此，其毒性<油基钻井液中柴油毒性的10%，且由于NSF的闪点约为134°C，相关火灾危险性较低。含NSF的合成基钻井液具有对储层无膨胀损害的优点，并且由于无需处理环境问题（硫和芳烃含量<0.5mg/L）以及钻井液与储层反应引起的现场问题，节省了钻井液成本，通过减少钻具粘附以及合成基流体中的碳-碳烃，极大地提高了机械钻速，安全使用，并且具有稳定的钻井液性能，即闪点（134°C）和低火灾危险性。因此，我们实现了制备一种芳烃和硫含量符合国际标准的高质量无毒合成液的目标。因此，使用这种合成基钻井液有利于环保钻井。
