摘要
磨料水射流在钻井提速、深穿透射孔和压裂增产等方面应用效果显著,深入认识磨料水射流破岩机理是提升其应用效果的关键之一。本文基于任意拉格朗日—欧拉耦合有限单元算法,提出了独立封装有限元网格描述磨料的方法,将水射流单元设定网格随物质的运动而变化以实现流体流动特性,速度设置给物质;将磨料单元设定网格不随物质的运动而变化以实现固体颗粒特性,速度设置给网格。综合考虑岩石的动态冲击损伤作用以及水射流和磨料的协作,建立了可表征水射流流动和岩石损伤破坏的多相多物理场耦合过程的磨料水射流破岩模型,模型聚焦磨料颗粒和水射流对岩石微秒级的冲击破坏。采用2套网格捕捉磨料和水射流的协同破岩作用,得到了岩石破碎体积、岩石损伤场、水射流压力场、水射流和磨料对岩石破碎的能量贡献率等关键参数的时空演化特征。结果表明,磨料水射流破岩过程磨料起主导作用,水射流起辅助作用。分析得到磨料水射流中磨料—水射流协同破岩机理认识,磨料撞击岩石使岩石局部产生的高程度损伤降低了水射流破岩的难度,此外磨料冲击破碎岩石使得水射流和岩石之间产生新界面,促使水射流的冲击压力升高,提高了水射流的破岩能力,因此磨料水射流中的水相比于纯水射流具有更高的射流打击力和能量利用率,磨料冲击预损伤岩石叠加水射流聚集增压的磨料—水射流协同作用破岩是磨料水射流破岩效率和能量利用率高于纯水射流数倍的重要机理之一。研究结果对优化磨料水射流破岩参数提供了理论模型和设计依据。
The abrasive water jet has remarkable effect in the application of accelerating drilling speed,deep penetration perforation and fracturing stimulation.In-depth understanding of the mechanism of abrasive water jet rock breaking is one of the keys to improve its application effect.Based on the arbitrary Lagrange-Euler finite element coupling algorithm,an independent packaged finite element mesh method for describing abrasives is presented in this paper.The grid of the water jet unit is set to change with the movement of the material to realize the fluid flow characteristics,and the speed is set to the material.The abrasive unit is set to the grid does not change with the movement of the material to achieve the solid particle characteristics,and the speed is set to the grid.Considering the dynamic impact damage of rock and the cooperation between water jet and abrasive,an abrasive water jet rock breaking model was established to characterize the multi-phase and multi-physical coupling process of water jet flow,rock damage and failure.The model focused on the impact damage of abrasive particles and water jet on rock in microseconds.Two sets of meshes were used to capture the collaborative rock breaking action of abrasives and water jets,and the temporal and spatial evolution characteristics of key parameters such as rock breaking volume,rock damage field,pressure field of water jet and energy contribution rate of water jet and abrasive to rock breaking were obtained.The results show that abrasive plays the main role and water jet plays the auxiliary role in the process of rock breaking.The mechanism of abrasive and water jet cooperative rock breaking is analyzed.The abrasive impingement of rock causes high degree of local damage of rock,which reduces the difficulty of water jet breaking rock.In addition,the impact of abrasive water jet on rock breakage creates a new interface between water jet and rock,which increases the impact pressure water jet and improves the rock breaking ability of water jet.Therefore,water in abrasive water jet has higher impact force and energy utilization rate than that of pure water jet.The predamage of abrasive impact on rock combined with the higher pressure of water jet stagnation is one of the important mechanisms that abrasive water jet has several times higher efficiency and energy utilization than pure water jet.The results can provide a theoretical model and design basis for optimizing the rock breaking parameters of abrasive water jet.
作者
徐鹏
盛茂
田守嶒
王天宇
XU Peng;SHENG Mao;TIAN Shouceng;WANG Tianyu(State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum-Beijing,Beijing 102249,China)
出处
《石油科学通报》
CAS
2024年第4期627-636,共10页
Petroleum Science Bulletin
基金
国家自然科学基金优秀青年科学基金项目“油气井流体力学与工程”(编号:52122401)资助。
