EDEM最新应用研究—钻头磨损模拟

Nowadays, underground structures play a vital role in the development of various countries. These structures are constructed as part of many civil activities, such as the development of road and railways, tunnels, underground subways, gas and sewage lines, fuel storage, military installations and more. Drilling is a key operation in the design and construction of such projects. But it is not only tunnelling that characterizes our era. Overpopulation and extensive industrial activities are the driving forces leading to continuous demand for energy. In the quest for more hydrocarbons, drilling has extended to both deep water areas and to very deep wells. In these extreme conditions, varying temperatures (1-200℃) and high pressures (more than 1.000 bars) are frequently encountered leading to operation adversities and significant equipment wear.

Being able to model drilling problems and accurately predict the wear of the drilling tools is of high importance and a challenging computational task. The wear results in considerable changes of the shape of the drilling tools which has a direct effect on the overall efficiency of excavation works. Firstly, because of its adverse effect on cutting forces, excavation rate and energy consumption, and secondly, due to the costs and delays incurred by replacements of the worn-out tools. Therefore, being able to accurately predict wear is an important element in the design and optimization of cutting tools.

能够模拟钻井问题并准确预测钻具的磨损是非常重要的和具有挑战性的计算任务。磨损会导致钻孔工具的形状发生相当大的变化，这直接影响了挖掘工程的整体效率。首先是由于其对切割力，挖掘率和能量消耗的不利影响，其次是由于更换磨损工具所造成的成本和延误。因此，能够准确预测磨损是切削刀具设计和优化中的重要因素。

Drilling rig

钻机

The Discrete Element Method (DEM) is commonly regarded as a suitable tool used in soil and rock mechanics to describe the mechanical behavior of granular materials and geomaterials. DEM can be used to investigate a range of applications at the particle scale -including drilling processes- and to monitor the interaction between materials and equipment in detail. The latter is of great importance in industrial applications as one of the basic problems in drilling is the tool wear and this depends on both mechanical and thermal effects in the tool-rock interaction. More specifically, high temperatures developed on the tool surface due to heat generated by friction between tool and rock reduce the hardness of the surface and increase adhesive and abrasive wear. Using a DEM tool provides the ability to model such processes and identify the regions in which wear is taking place.

离散元素法（DEM）通常被认为是土壤和岩石力学中用于描述颗粒材料和地质材料的机械性能的合适工具。DEM可用于研究颗粒尺度的一系列应用，包括钻孔工艺，并详细监测材料和设备之间的相互作用。后者在工业应用中非常重要，因为钻孔的基本问题之一是刀具磨损，这取决于工具-岩石相互作用中的机械和热效应。更具体地，由于工具和岩石之间的摩擦产生的热量，在工具表面上产生的高温降低了表面的硬度并增加了粘合剂和磨料磨损。使用DEM工具提供了对这些过程进行建模和识别发生磨损的区域的能力。

Example case: DEM simulation of Tricone drilling operation. Provided by Dr. Nima Gharib (McGill University, Canada)

Drilling and blasting are important preliminary tasks in surface mining, where Tricone bits are preferred in most rotary applications for blasthole drilling. During the comminution process the bit is subjected to changes, known as bit wear, due to the contact between bit teeth ground formations. The bit wear will affect the drill performance significantly, therefore it is vital to be aware of the bit wear condition in drilling process in order to achieve optimal drilling performance. To address these issues, a numerical model was developed to simulate the bit wear in rock and bit interaction. The model was aimed to simulate the gradual wear of bit inserts and the rate of penetration in contact with various rock formations.

钻孔和爆破是表面采矿中的重要初步任务，在大多数旋转钻孔如钻炮眼应用中，Tricone钻头是首选。在粉碎过程中，钻头由于齿面与地面之间的接触而发生变化，称为钻头磨损。钻头磨损会显著影响钻头的性能，因此在钻井过程中要了解钻头磨损状况，以达到领先钻井性能至关重要。为了解决这些问题，开发了一个数值模型来模拟岩石和钻头相互作用中的钻头磨损。该模型旨在模拟钻头刀片的逐渐磨损和与各种岩层接触的渗透速率。

Simulation of Tricone rotary drill bit showing regions of wear (color shows depth of wear)

Tricone旋转钻头模拟中磨损区域的显示（颜色显示磨损深度）

The Tricone drilling process was modeled using EDEM software, a cutting edge discrete element modeling package. The software was uniquely modified and optimized to simulate the drilling process which includes both the bit and the ground. Simulation of the drilling gave the applied forces on the drill body and the cones, vibration, penetration rate and the drill wear.Ground modeling simultaneously provided information about rock types, stratification, inclination angle and required energy for specified drilling conditions. Different rock types were defined which made it possible to estimate the bit’s life time in different working conditions.

Tricone钻井过程使用EDEM软件进行建模，EDEM软件是一个尖端的离散元件建模包。该软件进行了独特的修改和优化，以模拟包括钻头和地面的钻孔过程。可以模拟出钻头主体和锥体施加的力，振动，穿透率和钻头磨损。地面建模同时提供有关岩石类型，分层，倾斜角度和指定钻井条件所需能量的信息。通过定义不同的岩石类型，可以在不同的工作条件下估计钻头的使用寿命。

Simulation of Tricone drilling operation – Bit wear monitoring

Tricon钻井操作模拟 - 钻头磨损监测

The outcomes of this research will support a bit wear monitoring system in the next phases of the project. Such insight is directly applicable in bit manufacturing as it allows investigation and enhancement of product performance.

这项研究的结果将在项目的下一阶段支持钻头磨损监测系统。这样的研究可适用于钻头制造，因为它能够研究和增强产品性能。