变异型屋脊齿的破岩机理及齿形设计研究

【作者】 刘畅；

【导师】 杨迎新；

【作者基本信息】 西南石油大学 ， 机械工程， 2022， 硕士

【摘要】 国内外油气井资源埋深大,钻井开发难度高,地质结构复杂,深井超深井的数量和比例越来越大,钻遇的难钻硬地层越来越多,严重阻碍了油气资源的高效开发,现有PDC钻头在难钻硬地层中往往难以适应,使用效果不佳。为了提升PDC钻头在难钻硬地层的适应性,各种非平面PDC切削齿相继出现,因此PDC切削齿的聚晶金刚石层表面开始向多维发展。屋脊齿作为一种典型的非平面PDC切削齿,通过棱脊以强集中力的方式吃入岩石,在硬地层侵入能力强,现场应用数据表明:与平面齿相比,屋脊齿具有更好的抗冲击性和抗研磨性。为了进一步提高屋脊齿的破岩效率,提出一种新型变异型屋脊齿,为探究变异型屋脊齿的破岩机理,本文主要开展了以下研究工作:(1)开展平面齿、屋脊齿破碎岩石的数值模拟研究,获取两种切削齿破岩规律,根据两种切削齿破岩特性完成了变异型屋脊齿的结构设计。(2)开展变异型屋脊齿破岩数值模拟研究,研究切削齿脊长、脊倾角、内凹圆弧曲面半径、脊角、圆角等结构参数和前倾角、吃入深度等工作参数对变异型屋脊齿破岩效率的影响规律,获得切削齿齿面、岩石表面应力分布规律,从而阐述变异型屋脊齿的破岩机理。(3)开展变异型屋脊齿的单齿切削试验,对有限元仿真模型进行验证,研究平面齿、屋脊齿、变异屋脊齿不同齿形下岩石的破碎形式、岩屑形态以及破碎刮痕或井底模式的特征与差别,同时测试分析切削齿的破岩切削载荷、切削载荷波动情况以及破岩能耗。(4)开展全尺寸钻头钻进破岩仿真,测试获取平面齿、屋脊齿、变异型屋脊齿钻头扭矩、机械钻速等参数,对比分析变异型屋脊齿钻头与常规PDC钻头的工作载荷、钻头破岩效率以及破岩能耗。本文的通过实验与数值模拟相结合的方式对变异齿屋脊齿破岩机理展开研究,研究结果表明:1.变异型屋脊齿的吃入岩石的能力和破岩效率均高于常规屋脊齿和平面齿。2.脊长越短,变异型屋脊齿的破岩效率越高,在实际应用时应保证吃入深度大于脊长。3.负脊倾角有利于提高变异型屋脊齿的破岩效率,正脊倾角有利于提高变异型屋脊齿的使用寿命,应根据钻进地层选择变异型屋脊齿的脊倾角。4.变异型屋脊齿钻头的机械钻速比常规屋脊齿高19.75%,比平面齿钻头高44.97%,变异型屋脊齿对PDC钻头在硬地层的提速效果明显。本文针对变异型屋脊齿破岩机理和破岩规律的研究工作,为难钻地层非平面PDC切削齿的设计和应用提供了新的理论参考。更多还原

【Abstract】 At domestic and abroad,oil and gas well resources are buried deeply,drilling and development are difficult,geological structure is complex,the number and proportion of deep wells and ultra-deep wells are increasing,and more and more hard-to-drill formations are encountered,which seriously hinders the efficient development of oil and gas resources.Existing PDC bits are often difficult to adapt to hard-to-drill formations,and the use effect is not good.In order to improve the adaptability of PDC bits in hard-to-drill hard formations,various non-planar PDC cutting cutter appear one after another,so the surface of polycrystalline diamond layer of PDC cutting cutter begins to develop in multi-dimensions.As a typical non-planar PDC cutting tooth,the roof tooth eats into the rock with a strong concentrated force through the ridge,and has a strong invasion ability in hard strata.Field application data show that the roof tooth has better impact resistance and abrasion resistance than the planar tooth.In order to further improve the rock-breaking efficiency of roof cutter,a new type of variant roof cutter is put forward.In order to explore the rock-breaking mechanism of variant roof cutter,this paper mainly carried out the following research work:(1)Carry out numerical simulation research on rock breaking by plane cutter and roof cutter,obtain rock breaking laws of two kinds of cutting cutter,and complete structural design of variant roof cutter according to rock breaking characteristics of two kinds of cutting cutter.(2)Carry out numerical simulation research on rock breaking of variant roof cutter,study the influence of structural parameters such as cutting tooth ridge length,ridge inclination,concave arc radius,ridge angle,fillet and other working parameters such as rake angle and intake depth on rock breaking efficiency of variant roof cutter,and obtain the stress distribution law of cutting tooth surface and rock surface,so as to elaborate the rock breaking mechanism of variant roof cutter.(3)Carry out the single-tooth cutting experiment of variant roof cutter,verify the finite element simulation model,and study the characteristics and differences of rock crushing forms,cuttings shapes,crushing scratches or bottom hole patterns under different tooth shapes of plane cutter,roof cutter and variant roof cutter.At the same time,test and analyze the rock breaking cutting load,cutting load fluctuation and rock breaking energy consumption of cutting cutter.(4)Carry out rock breaking simulation of full-size drill bit,test and obtain parameters such as plane cutter,roof cutter,torque of variant roof cutter bit,penetration rate,etc.,and compare and analyze the working load,rock breaking efficiency and energy consumption of variant roof cutter bit and conventional PDC bit.In this paper,the rock-breaking mechanism of the roof cutter with variable cutter is studied by means of experiment and numerical simulation.The results show that:1.The rock-eating ability and rock-breaking efficiency of variant roof cutter are higher than those of conventional roof cutter and plane cutter.2.The shorter the ridge length,the higher the rock breaking efficiency of the variant roof cutter.In practical application,it should be ensured that the eating depth is greater than the ridge length.3.Negative ridge inclination is beneficial to improve rock breaking efficiency of variant roof cutter,while positive ridge inclination is beneficial to improve service life of variant roof cutter.The ridge inclination of variant roof cutter should be selected according to drilling stratum.4.The mechanical drilling speed of the variant roof tooth bit is 19.75%faster than that of the conventional roof tooth bit and 44.97%faster than that of the plane tooth bit.The variant roof tooth has obvious speed-up effect on PDC bit in hard stratum.In this paper,aiming at the research work of rock breaking mechanism and rock breaking law of variant roof cutter,it provides a new theoretical reference for the design and application of non-planar PDC cutting cutter in difficult-to-drill strata.更多还原