移动线形激光破岩耦合场仿真分析及实验研究

将激光技术与传统钻井技术相结合以实现高效破岩在油气开采领域具有极其重要的价值与前景。目前国内对静止点光束作用于岩石的破碎规律有一定的研究,而未对移动及不同形状激光束作用于岩石的破碎规律做相关研究。本文以实际钻井工况为背景,建立线形激光能量场分布数值模型,通过传热学相关理论建立了移动线形激光温度场分布数值模型。采用COMSOL Multiphysics有限元仿真软件对移动线形激光作用花岗岩过程进行了热力耦合瞬态仿真,得到了移动线形激光作用花岗岩温度场的分布规律,以莫尔-库伦破坏准则为依据,仿真模拟了激光热应力作用下花岗岩的破损形貌。通过实验数据与仿真结果对比,验证了移动线形激光破岩温度场分布数值模型的合理性。由激光辐照前后花岗岩密度、孔隙度、单轴抗压强度的变化程度,得到了上述参数下激光对岩石损伤的相关数据,对合理匹配激光、机械两部分相关参数提供了一定数据支撑。

Simulation analysis and experimental research on coupling field of mobile linear laser rock breaking

Combining laser technology with traditional drilling technology to achieve high efficiency rock breaking has extremely important value and prospect in the field of oil and gas exploitation.At present,there are some researches on the fracture law of rock by the light beam of static point in China,but there is no related research on the fracture law of rock by the moving laser beam and different shapes of laser beam .Based on the actual drilling conditions,this paper establishes a numerical model of linear laser energy field distribution,and establishes a numerical model of temperature field distribution of moving linear laser through the theory of heat transfer.Using COMSOL Multiphysics finite element simulation software,the thermal-mechanical coupling transient simulation of the moving linear laser-induced granite process was carried out.The temperature distribution of the moving linear laser-induced granite was obtained.Based on the Mohr-Coulomb failure criterion,the damage morphology of the laser-induced granite was simulated.By comparing the experimental data with the simulation results,the rationality of the numerical model of temperature field distribution in rock breaking by moving linear laser is verified.According to the variation of density,porosity and uniaxial compressive strength of granite before and after laser irradiation,the related data of laser damage to rock under the above parameters are obtained,which provides some data support for matching laser and mechanical parameters reasonably.