三通道闭式循环空气锤钻进系统流场分析

发布时间：2018-04-10 09:43

本文选题：油气资源勘探　切入点：闭式循环空气锤　出处：《吉林大学》2017年硕士论文

【摘要】：随着全球经济的发展,人类对能源的需求增加,导致常规油气资源的储量与规模逐渐减小,开发难度日益提高。同时,非常规能源储量庞大,具有接替常规油气资源的潜力,但其开发难度大,因此对勘探开采所需技术要求提高。我国油气资源储量相对匮乏,且多处于地质条件复杂的区域。为解决钻进过程所遇到的难题,提高钻进效率,节约钻进成本,创新提出具有三通道的闭式循环空气锤冲击回转钻进工艺,该钻井工艺主要特点在于压缩气体独立循环驱动空气锤高效冲击回转钻进,同时配合钻井泥浆循环排渣并保护孔壁稳定。其钻具系统主要包括:同轴三壁钻杆、闭式循环空气锤及相应的球齿钻头。本文对该钻进系统的各个流场进行数值模拟分析,包括同轴三壁钻杆内的气体流场、闭式循环空气锤内的气体流场以及孔底钻头处的钻井泥浆流场,具体研究内容和结论主要有:1.利用Flow Simulation软件对同轴三壁钻杆内的气体流场进行分析。首先对三种不同结构的接头方式进行局部流场分析,确定最优的接头结构。再为最优接头结构设计不同的尺寸参数,并对其进行合理优化。结果表明,当钻杆接头的导向凸台伸出接头底端一定距离时,钻杆的压力损失可大幅降低;钻杆接头的结构尺寸对压力降的影响相对较小。最终分析单根钻杆的气体流场通道在不同供气条件下的压力损失情况。钻杆压力降随着供气压力的升高而降低,随着供气量的增加而升高。2.对闭式循环空气锤的流场进行分析,其压力损失主要包括两个方面,分别为压缩气体驱动潜孔锤做功所消耗的能量和压缩气体在内部通道流动所形成的压力损失。利用AMESim软件对闭式循环空气锤工作过程进行模拟分析,确定其在不同的供气条件下的工作情况,为钻进过程中空压机的参数设置提供依据。分析结果表明,随着供气压力的增加,闭式循环空气锤的工作性能提高,但压缩气体的流量也相应增加,对空压机的要求提高。利用Flow Simulation软件计算不同压力条件下,压缩气体在潜孔锤内部通道的压力损失。供气压力升高,闭式循环空气锤内通道的压力损失降低,且随着供气压力的升高,压力损失下降的趋势减小。3.对孔底钻头处的钻井泥浆流场进行模拟,利用Fluent软件分析钻头水口在不同直径和不同倾斜角度时孔底的流场情况。分析结果认为,钻头水口直径越小,越有利于孔底清洗和辅助碎岩,但对泥浆泵的功率要求提高。钻头水口的倾斜角度过大或过小都不利于孔底岩屑的清洗和运移,倾斜角度为15°时能达到更好的清洗孔底的效果。为钻头结构的优化设计和钻井工程中泥浆泵工作参数的选取提供了理论依据。
[Abstract]:With the development of global economy, the demand for energy is increasing, which leads to the decrease of reserves and scale of conventional oil and gas resources and the increasing difficulty of development.At the same time, the unconventional energy reserves are huge and have the potential to replace the conventional oil and gas resources, but it is difficult to develop, so the technical requirements for exploration and exploitation are raised.Oil and gas reserves in China are relatively scarce, and most of them are located in regions with complicated geological conditions.In order to solve the problems encountered in drilling process, improve drilling efficiency and save drilling cost, a three-channel closed circulation air hammer percussive rotary drilling technology is proposed.The main feature of this drilling process is that the compressed gas independent circulation drives the air hammer high efficiency percussive rotary drilling, at the same time, the drilling mud circulates slag discharge and protects the hole wall stability.Its drilling tool system mainly includes: coaxial three-wall drill pipe, closed circulation air hammer and corresponding ball bit.In this paper, the numerical simulation and analysis of each flow field of the drilling system are carried out, including the gas flow field in the coaxial three-wall drill pipe, the gas flow field in the closed circulation air hammer and the drilling mud flow field at the hole bottom bit.Specific research content and conclusion mainly have 1: 1.The gas flow field in coaxial three-wall drill pipe is analyzed by Flow Simulation software.Firstly, the local flow field of three kinds of joints with different structures is analyzed to determine the optimal joint structure.Then, different dimension parameters are designed for the optimal joint structure, and the reasonable optimization is carried out.The results show that the pressure loss of the drill pipe can be greatly reduced when the bottom end of the drill pipe joint is at a certain distance, and the influence of the structure size of the drill pipe joint on the pressure drop is relatively small.Finally, the pressure loss of the gas flow channel of a single drill pipe under different gas supply conditions is analyzed.The pressure drop of drill pipe decreases with the increase of gas supply pressure and increases with the increase of gas supply.The flow field of a closed circulation air hammer is analyzed. The pressure loss mainly includes two aspects: the energy consumed by the work done by the compressed gas driven DTH hammer and the pressure loss caused by the compressed gas flowing in the internal channel.The working process of closed circulation air hammer is simulated and analyzed by using AMESim software, and its working conditions under different air supply conditions are determined, which provides the basis for the parameter setting of air compressor during drilling.The results show that with the increase of air supply pressure, the working performance of closed cycle air hammer is improved, but the flow rate of compressed gas is also increased, and the requirement of air compressor is raised.Flow Simulation software is used to calculate the pressure loss of compressed gas in the inner channel of DTH hammer under different pressure conditions.With the increase of air supply pressure, the pressure loss of the inner passage of closed circulation air hammer decreases, and with the increase of air supply pressure, the pressure loss decreases by .3.The drilling mud flow field at the hole bottom bit is simulated, and the flow field of the hole bottom at different diameters and inclined angles is analyzed by Fluent software.The analysis results show that the smaller the diameter of bit nozzle is, the more favorable the hole bottom cleaning and auxiliary rock breaking is, but the higher the power requirement of mud pump is.Too large or too small inclined angle of bit nozzle is not conducive to cleaning and migration of hole bottom cuttings, and a better effect of cleaning hole bottom can be achieved when the inclination angle is 15 掳.It provides a theoretical basis for the optimum design of drill bit structure and the selection of working parameters of mud pump in drilling engineering.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE92

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