海洋深水浅层井壁稳定与水合物抑制的机理和新方法研究

The drilling and development of oil, gas resources in deepwater formation is going to be a hot spot and forefront of technological innovation in the global oil industry. As "drilling blood", drilling fluids used in deepwater face unprecedented technical challenges, such as wellbore stability problems in the shallow formation, control troubles of hydrate formation in deepwater wellbore, rheology control difficulties under low temperature and other technical bottle necks as well as key basic scientific problems. With the rapid development of nanotechnology, nano materials with curious properties are expected to provide new ways and methods to address these challenges. Based on the surface effect, size effect, macroscopic quantum tunneling and other features and mechanics of nano materials and new progress in interface colloid chemistry, micro fracture mechanics and interdisciplinary, this project intends to focus on the principles of nanotechnology which can be used to enhanced borehole stability in deepwater shallow formation, and reveal the basic law and inhibition mechanism of nano materials about how to inhibit gas hydrate formation in deepwater wellbore. Finally, the structure and preparation methods of the new nano treatment agents will be designed and optimized, used to enrich and develop drilling fluid theoretical system for deepwater drilling, which can provide scientific theories and methods for the development of oil, gas resources under deepwater conditions, promoting the development process of China's deepwater drilling.

海洋深水油气钻探开发将成为世界石油工业的热点及科技创新的前沿。海洋深水钻井液作为"深水钻井工程的血液"，面临前所未有的技术挑战，如海底浅层井壁稳定、深水井筒中天然气水合物抑制、低温流变性调控等技术瓶颈及关键基础科学问题。随着当代纳米技术飞速发展，利用某些纳米材料的新奇特性，可望为解决这些难题提供新的途径及方法。本项目基于纳米材料的表面效应、尺寸效应、宏观量子隧道效应等特性，结合界面胶体化学和微观断裂力学等交叉学科的新进展，拟重点探讨基于微观纳米尺度的深水浅层井壁稳定原理和方法，揭示深水井筒中天然气水合物生成的基本规律及纳米材料的抑制机理，设计优化新型纳米基处理剂的结构及制备方法等，丰富和发展海洋深水钻井液基础理论，为海洋深水钻井工程提供科学理论和方法支撑，促进我国海洋深水油气资源的钻探开发进程。

海洋深水钻井工程面临着浅部地层井壁失稳以及天然气水合物生成难题，影响钻井安全与效率。为此，本项目结合纳米技术新进展，围绕深水浅层井壁稳定及水合物控制新方法开展基础研究。首先建立了深水浅部弱胶结地层井壁稳定性模拟实验方法，分析了钻井液防塌剂在深水浅部地层的胶结固壁作用，基于“多元协同”稳定井壁理论，提出了深水浅层稳定井壁物理化学方法。研制出了深水钻井液低分子量（26万）包被抑制剂，对活性泥页岩具有强包被抑制性，并可避免传统高聚物包被剂造成的钻井液低温严重增稠；研制出具有物理封堵和水化抑制双重作用的纳米聚合物微球封堵剂，并揭示了其作用机理。建立了钻井液中水合物生成动力学分析新方法，分析了深水钻井液中水合物生成的热力学和动力学特性以及水合物抑制剂作用机理，发现了钻井液抑制水合物生成效果与水活度的线性关系，以及氯化钠与动力学抑制剂的协同增效作用。探讨了7种纳米材料对水合物生成的影响规律及机理，研发了新型水合物动力学抑制剂，抑制水合物生成效果是传统抑制剂PVP的3倍以上。在本项目研究成果指导下形成的具有自主知识产权的深水钻井液体系已在我国南海深水气田成功开展现场应用，推动了我国深水钻井液理论与技术的发展，相关成果获得2018年中国石油和化学工业联合会科技进步一等奖，体现了本项目研究成果的学术价值和工程实践意义。