多路高低压复合脉冲等离子体高效破岩钻井方法及应用基础

Exceeding the traditional electrical discharge machining, a new high-efficiency plasma drilling method with multichannel high-low voltage composite pulse plasmas rotating rock breaking and decreasing tool electrode wear by magnetic confinement is presented. Microscopic physical properties of the high-low voltage composite pulse plasma, mechanisms of energy transformation and material erosion are investigated, and the microphysical nature of rock breaking for this method is revealed. The physical essence of tool electrode wear for multichannel high-low voltage composite pulse plasmas rock breaking is revealed, a new method which can reduce tool electrode wear is found. The design methods of multichannel high-low voltage composite pulse plasma drill and its driving device at downhole are researched, the drill and device are developed. The topological structure and control strategy of the high-low voltage composite pulse plasmas rock breaking pulse generator are investigated, the pulse generator circuit configuration is optimized, and the pulse generator is developed. Drilling technology with multichannel high-low voltage composite pulse plasmas rock breaking is investigated, technological law of this method is found. The topological structure and control strategy of energy partitioned pulse plasma power will be studied and this efficient plasma drilling power unit will be designed. Theoretical and experimental researches are done in this project, a new high-efficiency plasma drilling method with multichannel high-low voltage composite pulse plasmas rock breaking is developed with independent intellectual property rights. Moreover, the project will establish the application foundation theory system of the new method, increase the content and theory of modern oil and gas drilling engineering, and accelerate the practical application of the new drilling technology.

突破传统的等离子体破岩钻井技术，率先提出采用多路高低压复合脉冲等离子体旋转扫射破岩及外加磁场约束等降低等离子体破岩工具电极损耗，实现等离子体高效钻井的新方法。研究高低压复合脉冲等离子体微观物理特性、能量转化及破岩机理，揭示其破岩的微观物理本质；研究探明多路高低压复合脉冲等离子体破岩工具电极损耗的物理本质，寻找出可降低破岩工具电极损耗的新方法；研究多路高低压复合脉冲等离子体破岩钻头及其井下驱动装置的设计方法，优化设计出等离子体破岩钻头及其井下驱动装置；研究高低压复合脉冲等离子体破岩脉冲电源的拓扑结构和控制策略，优化其电路结构，研制出该脉冲电源；研究多路高低压复合脉冲等离子体高效破岩钻井工艺，揭示其工艺规律。通过本项目的理论与实验研究，研发出具有自主知识产权的多路高低压复合脉冲等离子体高效破岩钻井新方法，建立其应用基础理论体系，丰富现代油气钻井工程的理论和内容，加快该新型钻井方法的实用化步伐。

针对常用的机械破岩钻井方法钻遇硬岩时存在破岩效率低、钻头磨损严重、钻井速度慢和成本高等问题，研发出了具有自主知识产权的多路高低压复合脉冲等离子体高效破岩钻井新方法。该方法的破岩钻井效果不受岩石的硬度和强度等影响，具有破岩效率高、成本低等优点。率先提出设计多路分隔阳极设计实验系统进行等离子体微观物理特性研究的新方法，实验发现在等离子体放电过程中，阳极上会出现多个阳极弧根的新现象，且阳极弧根数量与等离子体电流大小密切相关；建立了等离子放电通道物理模型，揭示了多路高低压复合脉冲等离子体微观物理特性、能量转化及破岩微观机理。创新研制了等离子体破岩钻头中阳极损耗特性实验系统，研究揭示了等离子破岩钻头的阳极损耗机理，以及阳极损耗位置与等离子电流、气体流量、喷嘴长度等之间的规律关系，发现了阳极质量损失可以用弧功率衡量、阳极损耗的位置与阳极结构密切相关等新现象；提出了降低等离子破岩钻头工具电极损耗的方法。研究探明了多路高低压复合脉冲等离子体破岩钻头上等离子体发射头的尺寸和布置方式等对破岩工艺效果的影响规律关系；原创设计出了高效、长寿命等离子破岩钻头，并对其关键核心零部件进行了优化设计，研制出了该种新型等离子钻头以及等离子破岩钻井实验装置。提出了采用DC/DC变换控制策略和电压闭环反馈的高压低能调压脉冲电源设计方法，建立其控制系统数学模型，优化其电路结构；提出采用逆变和电流闭环反馈的低压高能调流脉冲电源设计方法，建立其控制系统数学模型，优化其电路结构；研制出了多路高低压复合脉冲等离子体破岩脉冲电源。研究探明了等离子电流、气流量、等离子喷嘴尺寸等对破岩工艺效果的影响规律等，构建了该创新技术的应用基础理论体系，为推进该技术的实际工程应用奠定坚实的工艺技术基础。