煤层气水平孔激光智能定向钻进工艺及煤岩破碎理化作用机理研究

Laser drilling and intelligent directional drilling with many well-known advantages are the development tendency within the area of drilling in future. Meanwhile, gas drilling has been wildly used in the horizontal directional drilling for coal bed methane. The integration of the three techniques will solve numerous questions in the horizontal directional drilling for coal bed methane..Based on the research results of the forms of coal breaking by laser, laser directional drilling tool, intelligent orientation algorithms, and in situ detection technology, this project will further focus on the intelligent laser controlling drilling orientation process, safe closed double gas circulation drilling process, physical and chemical acting mechanism of coal breaking by laser for coal bed methane horizontal directional drilling..By theoretical modeling, physical and chemical analysis, and self-made apparatus, this project will research the following four topics: (1) This project will research the intelligent laser controlling drilling orientation process for coal bed methane horizontal directional drilling; (2) This project will research the closed double gas circulation drilling process of laser drilling with safety and high efficiency in coal seam; (3) This project will research the mechanism of coal breaking in physical and chemical acting process by laser drilling; (4) This project will research the mechanism of borehole forming in fine coal seam by laser drilling, and (5) This project will manufacture the experimental apparatus for coal breaking by laser..The research achievements will lay a foundation for the substantial application research on the coal bed methane intelligent laser directional drilling process. This will be greatly instrumental to become the laser drilling into the practical productivity, thus solve all existing problems of horizontal directional drilling in coal seam and result in most significant breakthrough of exploration and development for coal bed methane.

激光钻井与智能钻井是未来钻井的发展趋势，其优势已得到国内外行业专家公认，而气体钻井已广泛应用于煤层气水平孔钻进中，这三种先进技术的有机结合，将从根本上解决现有煤层气水平孔钻进的诸多问题。本次申请在激光破碎煤岩形式和定向钻具设计的研究基础上，融合智能控向算法与原位探测技术，通过理论建模、理化分析、自制实验装置，深入研究煤层气水平孔激光智能定向钻进工艺、煤岩破碎理化作用机理。具体研究从五个方面展开：（1）煤层气水平孔激光智能控制定向钻进工艺；（2）煤层气激光钻进双气循环封闭式安全钻进工艺；（3）激光钻进煤岩破碎物理化学作用机理；（4）激光钻进软弱煤层烧结固化成孔机理；（5）激光钻进破碎煤岩实验装置。研究成果将对煤层气水平孔激光智能定向钻进的实质性应用研究奠定理论基础,更有利于率先将激光钻井技术应用于生产实际，全面有效地解决井下煤层气水平孔钻进现存问题，推动煤层气开采水平产生革命性改变。

本项目主要结合激光钻井、智能钻井与气体钻井的优势，在激光破碎煤岩形式和定向钻具设计的研究基础上，融合智能控向算法与原位探测技术，通过理论建模、理化分析、自制实验装置，深入研究煤层气水平孔激光智能定向钻进工艺、煤岩破碎理化作用机理。本项目主要通过激光钻进煤岩的数值仿真和室内实验等方法与手段，开展激光钻进煤岩机理、钻进工艺及钻进实验装置等方面的研究。项目组针对煤岩应用不同功率的激光器进行了多次的实验，基于COMSOL Mutiphysics软件建立了热-力-流多场耦合模型，揭示了激光辐照煤岩的孔眼演化过程及岩体内的温度场、应力场和流体场的分布情况。提出烧蚀成孔是激光钻进煤岩的主要成孔机制，热解、升华、烧结和氧化是煤岩在高温下主要的热烧蚀机制。根据实验结果，烧结的孔壁是煤炭焦化和燃烧的产物，能够提高松软煤层钻进时的孔眼稳定性；研究了氮气、空气等作为循环气体对钻进效果的影响；通过仿真和实验，研究钻井介质流量、激光功率、波长、照射时间、照射距离等与钻孔形状、深度和速度的关联性，揭示激光工艺参数对钻进过程的影响，提出适合煤层安全钻进的双气循环工艺；在多次实验和与设备厂商交流的基础上，研究并搭建了激光钻进破碎煤岩的实验装置，包括整体方案设计，开发集成控制系统开发、孔眼三维轮廓重建系统，设计围压加载系统、气体产物浓度检测系统等。研究成果为煤层气水平孔激光智能定向钻进的实质性应用研究奠定了理论基础,有利于率先将激光钻井技术应用于生产实际，解决井下煤层气水平孔钻进现存问题。