圆柱形PDC切削齿磨损对钻井工艺规程的影响  

Effect of Wear of Cylindrical PDC Cutting Teeth on Drilling Process

作　　者：任雷 祁任泽 何胜煜 卜长根[1] REN Lei;QI Renze;HE Shengyu;BU Changgen(School of Engineering and Technology,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)工程技术学院,北京100083

出　　处：《石油矿场机械》2024年第5期1-5,共5页Oil Field Equipment

基　　金：雄安新区科技创新专项“雄安新区地热资源高效钻井与开采新型技术应用研究”(2022XAGG0500)。

摘　　要：聚晶金刚石复合片(Polycrystalline Diamond Compact,PDC)钻头因其较高的耐磨性与钻井时效,在油气和地热的深部钻井中得到了广泛应用。PDC切削齿性能与切削齿磨损程度相关,直接影响钻头的寿命和钻进效率,所以研究切削齿的磨损对钻井工艺规程至关重要。针对切削齿在磨损阶段与岩石接触区域形状复杂、面积计算困难的问题,通过使用平面斜截复合片所在圆柱面的方法,推导出接触区域为部分椭圆,得到了接触面积与磨损高度、后倾角的函数表达式,分析了磨损高度、后倾角的变化对接触比压、片内剪应力的影响。结果表明:切削齿与岩石的接触面积受复合片磨损高度、后倾角大小的影响,磨损高度越大,后倾角越小,接触面积及面积变化率越大;相同载荷下的接触比压和片内剪应力随接触面积增大而越小。因此应根据复合片的磨损状态选择合适的钻井工艺参数,以维持PDC钻头的破岩效率。Polycrystalline diamond compact(PDC)bits are a common choice for deep drilling operations involving oil,gas,and geothermal wells.Their high wear resistance and drilling efficiency make them an optimal choice for such applications.The performance of PDC cutting teeth is dependent upon the degree of cutting tooth wear,which in turn affects the wear of the drill bit and the efficiency of the drilling process.Consequently,the study of cutting tooth wear is of paramount importance to the formulation of regulations pertaining to the machining process.To address the issue of calculating the complex shape and difficult areas of contact between cutting teeth and rock during the wear stage,a method utilizing a planar oblique section of the cylindrical surface where the composite piece is located was employed.This approach yielded the conclusion that the contact area is a partial ellipse and led to the derivation of a functional expression for the wear height,back rake angle,and contact area.Furthermore,the impact of alterations in wear height and back rake angle on contact specific pressure and intra-chip shear stress was examined.The results demonstrate that the contact area between the cutting teeth and the rock is influenced by the wear height and back rake angle of the composite piece.As the wear height increases,the back inclination angle decreases,resulting in an enlarged contact area and a higher area change rate.Consequently,the contact-specific pressure and the chip under the same load exhibit a downward trend as the contact area expands.Accordingly,the optimal drilling process parameters should be selected in accordance with the wear state of the PDC cutter in order to maintain the rock-breaking efficiency of the PDC drill bit.

关 键 词：PDC切削齿 磨损高度 接触面积 钻压 剪应力 

分 类 号：TE921.1[石油与天然气工程—石油机械设备]