汶川科学钻探PDC取心钻头有限元分析

A Finite Element Analysis on PDC Coring Bits Used in Wenchuan Scientific Drilling

汶川地震断裂带科学钻探项目是在龙门山"北川-映秀"断裂及龙门山前缘安县-灌县断裂附近实施5口科学群钻,由于所实施的5个钻孔都位于地震断裂带上,地层十分松软破碎,普通取心钻进的取心率低、岩心扰动大。为解决该问题,设计并采用了一种超前式隔水防冲蚀PDC取心钻头,取得了良好的效果,提高了岩心采取率,并保证了岩心的原状性。论文通过UG建立的实体模型导入ANSYS Workbench下的CFX流场分析和Steady-Thermal稳定热分析模块,分析了该钻头的井底流场分布、大小以及钻头的冷却效果,并计算孔底有效排粉的最低泵量,以确定超前式隔水防冲蚀PDC取心钻头取心钻进时保证取心率和岩心原状性要求的最优泵量。

The Wenchuan earthquake faults in the Longmen Shan Scientific Drilling Project is'Yingxiu-Beichuan'of the leading edge of the fracture and the Longmen County-near Guanxian fracture to implement five scientific drilling group,due to five drilling holes are located on earthquake fault,formation is very soft and broken,ordinary drill have low core recovery and large core disturbance. To address the low core recovery and large core disturbance,the design and the use of a Lead-type anti-erosion resisting PDC coring bits,and achieved good results,to improve the core recovery and ensure that the core of undisturbed nature. This article through import UG solid models to'CFX'flow analysis and'Steady-Thermal'stability thermal analysis module under ANSYS Workbench,to analyze the flow field of the distribution of the drilling,size,the cooling effect and calculate the minimum amount of effectively pump discharge powder in the bottom. Ensure the optimal amount of pump to improve the core recovery and ensure that the core of undisturbed nature in the drilling time of Lead-type anti-erosion resisting PDC coring bits.