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 pressur...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.展开更多
文摘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.
文摘四川盆地超深层油气的开发是钻探领域的重中之重。为满足超深井整个井身结构设计及钻进过程井筒稳定性的需要,针对四川盆地大尺寸井眼,以增强钻头稳定性、提高钻头破岩效率为目的,研制了Ф812.8 mm(32 in)PDC钻头,并在SDCK1井进行了现场应用。该钻头采用10刀翼设计,冠部采用稳定性较好的长锥形轮廓,并采用大小水眼混布方式提高切屑齿的冷却及井筒清洁效果。建立了Ф812.8 mm PDC钻头井底流场仿真模型,通过水力优化进行喷嘴倾角设计。研究及现场应用结果表明:钻井液喷射倾角为16°时在井底所形成的压力梯度和矢量图所表现出的效果较好;与牙轮钻头相比,研制的PDC钻头单趟钻进尺提高150%,单趟纯钻时间延长25.8%,平均机械钻速提高89%,钻头稳定性好,破岩效率高。研究结果可为四川盆地大尺寸井眼钻头设计提供指导。
