粒子射流冲击钻井破岩装置喷嘴研究

发布时间：2018-11-08 08:13

【摘要】：本文从粒子射流冲击钻井的固液两相流加速机理及破岩机理入手,分析了五种基本类型喷嘴流道圆柱型喷嘴、锥型喷嘴、锥直型喷嘴、流线型喷嘴及椭圆型喷嘴的结构及加速特点。建立了喷嘴的数学模型,给定粒子与钻井液的一个较为恰当的速度比率,计算不同结构喷嘴所需的加速轨道长度。设定统一参数,利用FLUENT模拟五种类型喷嘴流道的加速效果及流场特性,当收缩段与圆柱段比例适当时,锥直型、流线型和椭圆型三类喷嘴的两相流速度收敛性较好,加速效率较高。粒子射流冲击钻井钻头的中心位置的喷嘴可近似看作垂直喷射,边缘喷嘴喷射角度由位置确定,即喷嘴位置决定了其姿态。针对入射角度为20°的喷嘴,利用FLUENT模拟了单个锥直型、流线型和椭圆型三类喷嘴的运动状态,证明流线型和椭圆型喷嘴流道较为集中,且近似等速区间距离较大,利于破岩。对粒子射流冲击钻井钻头的多喷嘴分布,截取了中心喷嘴和任意一个边缘共两个喷嘴的布置面,并依据此设计了粒子射流冲击钻井钻头的流道。距离中心喷嘴30mm处分布四个边缘喷嘴,相邻两边缘喷嘴与中心喷嘴的连线呈90°夹角。建立中心喷嘴和边缘喷嘴两个喷射流道的模型,模拟喷嘴的结构、位姿对粒子和钻井液的加速效果的影响,证明喷嘴存在入射角度时,降低了喷射能量转化率。建立整体喷嘴的模型,研究钻井液和粒子满足破岩效果时,静态和旋转流场的井底压力状态,并根据粒子射流冲击钻井技术的环空流动规律、携岩机理,保证了在正常运作时,钻井液可携带粒子和岩屑上返的井底流场的清理。利用实验室改装的粒子射流冲击试验设备,对粒子射流冲击破岩进行了模拟研究,通过试验,证明了所设计的喷嘴流道可以满足钻井需要,相对于锥直型喷嘴的破岩效果,流线型喷嘴流道破岩效果较好。
[Abstract]:Starting from the acceleration mechanism of solid-liquid two-phase flow and rock breaking mechanism of particle jet impinging drilling, this paper analyzes five basic types of nozzle flow channel cylindrical nozzle, cone-straight nozzle. Structure and acceleration characteristics of streamline nozzle and elliptical nozzle. The mathematical model of the nozzle is established. Given a more appropriate velocity ratio of the particle to the drilling fluid, the accelerating track length required by the nozzle with different structures is calculated. The uniform parameters are set and the acceleration effect and flow field characteristics of five types of nozzles are simulated by FLUENT. When the ratio of the contraction section to the cylindrical section is appropriate, the velocity convergence of the two-phase flow is better for the cone-straight, streamlined and elliptical nozzles. The acceleration efficiency is high. The nozzle at the center of the particle jet impingement drilling bit can be regarded as a vertical jet approximately. The jet angle of the edge nozzle is determined by the position, that is, the position of the nozzle determines its attitude. For the nozzle with an incident angle of 20 掳, the movement state of a single straight cone nozzle, streamline nozzle and elliptical nozzle is simulated by FLUENT. It is proved that the flow channels of streamline and elliptical nozzles are more concentrated, and the approximate isokinetic interval distance is larger, which is favorable to rock breakage. For the multi-nozzle distribution of particle jet impingement drilling bit, the layout surface of two nozzles with center nozzle and any edge is intercepted, and the flow channel of particle jet impinging drilling bit is designed. Four edge nozzles are distributed from the center nozzle 30mm, and the connection between the adjacent two edge nozzles and the center nozzle is 90 掳angle. A model of two injection channels, the central nozzle and the edge nozzle, is established to simulate the structure of the nozzle and the effect of the orientation on the acceleration effect of the particle and the drilling fluid. It is proved that the injection energy conversion rate is reduced when the nozzle has an incident angle. The model of integral nozzle is established to study the bottom hole pressure state of static and rotating flow field when drilling fluid and particles satisfy the rock breaking effect. According to the annulus flow law of particle jet impingement drilling technology, the carrying mechanism of rock is ensured in normal operation. Drilling fluid can carry particles and cuttings back up the bottom-hole flow field cleaning. In this paper, the particle jet impingement test equipment is used to simulate the impact of particle jet on rock breaking. Through the experiment, it is proved that the designed nozzle runner can meet the requirements of drilling, and the rock breaking effect is compared with that of conical straight nozzle. The flow channel of streamline nozzle has good rock breaking effect.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE92

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