大修钻杆套铣松扣技术

大修处理卡钻事故一般采用爆炸松扣和套铣打捞等方法。在一些恶性卡钻事故中，由于被卡钻杆扣紧，爆炸松扣打捞后卡点以上剩余管柱无法倒扣捞出。针对此情况，本文提供一种套铣松扣的方法来解决倒扣问题。本文以钻杆接头模拟研究结果为基础，确定了套铣的对象是钻杆台肩和前三扣丝扣，再根据现场应用效果，从套铣头尺寸和材料两方面进行优化，提高了套铣松扣效率。现场应用表明，套铣松扣技术处理恶性卡钻事故倒扣问题既安全又高效。

Using Washover to Loosen Drill Pipe Thread Technique in Workover

Drill pipe frozen commonly uses string shot backoff and washover fishing in workover. In some malignant sticking accidents, due to the column clasped, the remaining column above free point can not be removed after string shot backoff fishing. The author provides a washover unscrewing method to solve backoff problem. This article first determines that the washover objects are shoulder of tool joint and the front three laps thread according to tool joint simulation results, then optimizes the size and material of the milling head based on the field application. It will help improve the efficiency of the washover unscrewing. Field application shows that washover unscrewing technique is safe and efficient in malignant sticking accidents.