Research of PDC Bit Compact Die With FEM and Optimum Method

In mould design, it is necessary for a designer to ensure that the cylinder has enough intensity in both the prestressed and synthesis states. An individual layer cylindrical mould cannot withstand a very high pressure needed in polycrystalline diamond composite (PDC) production. So, multi-layer prepressure combination assemble moulds are often used. The analysis conducted here is to study the interaction of cylindrical layers and to explain how to obtain enough load capability with the lowest requirement of material performance. The ratio of the pressure cylinder radius of synthetic diamond is 3.27, which is close to the optimal value and can be used as structure size in a design for PDC bit compact die. There is a linear relationship between the internal and external pressures under a special tangent stress on the inner wall of the pressure cylinder. So, when two of the three parameters (the internal pressure, external pressure, and the requirement value of the tangent stress on the inner wall of the pressure cylinder) are given, the third can be obtained. The sleeve acts as a bridge?between the pressure cylinder and the steel belts. The optimum model developed in this paper can be used in PDC bit compact die design and other similar prestressed cold extrusion die design.

Stress Analysis and Optimum Design of PDC Die for Offshore Drilling Engineering

The maximum internal tangential stress is a critical parameter for the design of the PDC （polycrystalline diamond compact） die that has been widely applied to offshore oil drilling. A new simple equation for the calculation of the stress is developed, and verified by the test data from Kingdream Corp. of China, the largest bit Company in China. An opti- mum method for the design of the PDC die is presented and demonstrated in detail, and software for the design and FEM analysis of the die is developed on the basis of the method. This software has been used in oil industry in recent years.

东海X区块钻井提速研究与应用

东海X区块地层可钻性较差,导致机械钻速低、钻头进尺短、井眼浸泡时间长、钻具遇阻遇卡,钻井效率低下,在对区内历史井地层特性、岩石抗压强度及钻头使用情况等分析的基础上,开展了钻井提速研究。结果表明,钻头优化、使用复合冲击器、井身结构优化的配套系统性提速方案可提高钻井效率、缩短钻井周期、降低复杂情况、加快油气勘探进程。其中,根据复合冲击器的工作原理和寿命优化井眼轨迹,对钻头设计时使用中等抛物线、加强肩部布齿密度,可解决区内钻头磨损严重、单个钻头进尺少需3~4趟钻完成一个井段作业、深部地层平均机械钻速低于10 m/h等一系列难题。该提速方案现场应用,减少了卡钻、井眼垮塌等井下复杂情况,实现了各开次井眼一趟钻工程,缩短钻井周期6~8 d,并在该区块创下了单只钻头进尺和机械钻速等多项新记录,钻井效率明显提高,为东海油气勘探提速增效探索了一条可行的技术路线。

改进PDC钻头性能的设计方法

在概述了现有PDC钻头的设计和制造情况的基础上, 从机械设计和水力设计 2个方面提出了优化设计PDC钻头和提高PDC钻头性能的方法, 并介绍了新型PDC钻头机械和水力结构设计的特点。实践证明, 利用数字化方法改进PDC钻头的设计比传统的试验方法具有设计周期短、成本低和准确度高的特点, 是一种可取的设计方法。

硬岩PDC定向钻头优化设计及其表面增材技术研究

定向长钻孔是煤矿瓦斯、水害治理的主要技术手段,PDC定向钻头性能是影响坚硬地层钻进效率的重要因素。针对煤层顶底板岩层定向长钻孔施工中出现因PDC钻头体断翼、PDC崩齿等问题导致的频繁起下钻、施工效率低等现象,采用等切削布齿原则对刀翼布齿进行优化,有效降低切削齿冲击破坏;通过流体力学仿真分析,优化钻头水力参数,保证岩屑及时排出孔底,防止切削齿因重复破碎岩石导致过早损坏;通过仿真分析,优选大直径PDC异型齿,提高切削齿耐磨和抗冲击性能;引入表面增材制造技术,通过优化等离子(PTA)增材制造工艺参数,实现了兼具胎体耐磨耐冲蚀和钢体强韧性的WC基复合钻头体加工工艺。新研制的PDC定向钻头,在淮南顾桥煤矿北区底板探放水钻孔中进行了现场试验。结果表明:钻进致密、坚硬灰岩地层时,2只钻头寿命分别达到827、810 m,相对于以前的ø120 mm胎体式定向钻头平均寿命300 m有较大幅度的提高,并降低了上下钻等辅助作业时间,提高了施工效率,达到了硬岩定向长钻孔提速增效的目标,为硬岩定向长钻孔用PDC钻头设计和制造工艺开发提供了新的解决方案。

钻头冠部剖面形状设计模式

通过对国内外ＰＤＣ钻头和金刚石钻头设计现状的调查，认为这两类钻头共有四种基本冠部剖面形状（浅锥型、双锥型、抛物线型和“Ｂ”型），提出了相应的四种钻头设计基本模式，探讨了各种模式适用性和所设计钻头特性。

临兴区块小井眼井钻头泥包原因分析及优化设计

随着环保政策的调整,钻井废弃物排放更加严格,山西临兴区块处于大开发阶段,需要进一步降本增效,所以开展了小井眼井钻井试验。在试验过程中多次出现了钻头泥包的现象,影响了作业的正常进行。从地层因素、钻井液、钻头选型、钻进参数等几个方面对钻头泥包现象进行了分析,并对后续小井眼井钻头进行了优化设计。优化调整后,现场作业表明,泥包现象得到了明显控制,钻井时效明显提高,与常规井眼相比,小井眼井钻井工期缩短30%。

临兴区块小井眼井钻头优化设计

山西临兴致密气区块小井眼钻井日益增多,但作业中出现了钻头泥包、机械钻速慢的问题,影响了作业高效进行。为了继续提高山西临兴区块致密气钻井效率,针对出现的钻头泥包和机械钻速过慢问题,在地层特性、地层可钻性、岩石强度研究等方面工作的基础上,开展了钻头优化设计研究。钻头的布齿密度可以从19 mm齿钻头优化为16 mm齿钻头;钻头后倾角可以由20°优化调整至约15°;侧倾角可以优化调整至10°以内。现场作业表明,使用优化调整后的钻头钻进,泥包得到明显缓解,机械钻速明显提高,工期缩短30%。该研究成果可以有效指导后续小井眼钻井作业,具有良好的推广价值。