强造斜致绳索取心钻具折断分析

在定向钻探固体矿产领域,通常在造斜段使用螺杆钻具,大部分的工作量采用取心回转钻进。造斜段使用螺杆钻具,钻杆不回转,受力较简单;如遇强造斜转换绳索取心钻具稳斜钻进,下部钻具组合容易出现回转困难、下不到底的技术难题,甚至出现丝扣折断事故。为避免强造斜对绳索取心钻具的影响,本文通过建立强造斜段对绳索取心钻具的几何约束变形模型,量化分析强造斜段岩心外管长度与造斜强度、环空间隙之间的约束关系,提供了可快速预判下部钻具参数能否满足强造斜安全钻进的方法。该方法在山东某铁矿定向孔的强造斜致下部钻具折断的事故处理中,通过对绳索取心钻具安全计算模型校核和调整钻具参数,实现了绳索取心钻具通过造斜率0.62°/m的强造斜段安全钻进至靶点,证明对强造斜绳索取心工具安全钻进预测和事故处理计算具有指导意义。

Analysis and treatment for accidents of the broken wire-line coring pipe in reinforced deflecting

Directional drilling uses positive displacement motor (PDM drill) mostly in the deflecting interval, and most of the workload adopts coring rotating drilling method. Drilling pipe do not rotate when using the PDM drill, the force is relatively weaker. After the reinforced deflecting and then coring drilling in hole angle, it is difficult to rotate and unable to run to the bottom for large size coring BHA, even broken accident for large size coring BHA on thread part. Combining with the example of the broken drilling pipe caused by the reinforced deflecting in a certain iron ore mine in Shandong Province, a geometrically constrained deformation model of the full-bore coring BHA with the deflecting interval is established, which provides the method of technical optimized parameters to avoid the breaking accident of the-drilling pipe in the reinforced deflecting.