高静压下高效激波与岩层物性耦合机制及其改造效果研究

The repetitive electrohydraulic shock waves can remove perforation blockage and generate micro-cracks near the well, therefore, enhance the permeability of the reservoir. This technology has a prospect in the oil well stimulation with the characteristics of safety, high efficiency and environmental friendliness. The initiation and propagation of shock wave and its effect on the reservoir are significantly influenced by the hydrostatic pressure, thus this technology is not extensive used in the field application yet. This application puts forward an exploratory study on the control method of high efficiency shock waves under high hydrostatic pressure and the coupling mechanism between shock waves and physical properties of rock. The strong shock wave can be obtained based on the plasma channel regulation method. Based on the similarity theory, the correlation model of electrohydraulic shock wave generation and propagation is established. The developed device is optimized according to the operating distance and shock wave parameters. The mechanism of repetitive shock waves on rock and physical properties of micro-cracks are studied. The analysis can provide theoretical support and technical reserve for the similar applications of shock waves.

利用液电效应辐射的强力激波作用于油井储层段，解除射孔堵塞，增加岩层裂缝进而实现增产，具有安全、高效、环境友好等特点。地层深处的高静压对激波产生、传播过程及其与岩层物性的耦合特性有极大影响，作用规律复杂，导致难以根据储层地质特点选择合理的激波作业参数与评估作业效果，严重制约了该技术的现场应用。本申请提出高静压下高效激波调控方法、激波与岩层物性的耦合机制及改造效果评估的探索性研究。研究多介质耦合强电场畸变的等离子体通道调控技术，实现高静压、小作业空间内的高效激波调控；基于相似理论的数学方程分析法建立电气-激波产生、传播关联模型，结合作业距离、激波参数需求定量优化装置的电气参数；研究高静压下重复频率激波载荷与岩层物性的耦合机制及其对微裂缝诱导、累积扩展规律，提出结合岩层物性、静压等因素的激波参数优化、调控的一般性分析方法。上述研究将为激波增产应用提供理论支撑。

重复频率施加的液电激波作用于高静压岩层时，激发岩层裂纹网络的生成和发展，扩展渗流、渗气通道，提高岩层孔隙度、渗透率，进而实现油气增产。搭建了液体电介质脉冲放电的电气-光学-激波综合观测实验平台，探究了液体电介质内流注放电机理、影响因素及变化规律，分析了放电参数对于激波的影响效果，提出了高静压下基于多介质耦合强电场畸变的高效激波调控方法。进行高静压下电气-激波产生、传播关联模型及参数优化控制的研究，考虑液电激波和岩石物性耦合作用下激波荷载的传播衰减规律，建立了液电激波荷载模型。分析了高静压下激波载荷对岩层微裂缝诱导、扩展机理及规律影响特性，揭示了液电激波和岩石物性耦合作用下微裂纹的激发和累积扩展规律，建立了放电能量对裂纹网络分布及扩展规律的影响模型。针对高静压下多参数耦合的工况，提出了岩层裂纹扩展规律的优化方法，并搭建了液电脉冲激波油气增产样机对油气岩层物性进行改造，取得了较好的增产效果，为加速激波增产技术的推广应用提供技术支撑。