钻井液连续循环钻井技术及自动化装备设计

Drilling fluid continuous circulation drilling technology and automatic equipment design

摘要:

钻井施工中，拆装钻杆需中止钻井液循环，但钻井液循环中止会导致孔内岩屑下沉、钻井液当量循环密度浮动变化，进而影响孔内安全。为避免上述情况的发生，钻井液不间断循环钻井技术的构想被提出。通过连续循环系统或连续循环接头进行钻井液分流，避开钻杆拆装部分，维持井内的钻井液循环，稳定钻井液当量循环密度。针对该技术原理，提出了一种自动化的钻井液不间断循环井口设备，通过背钳、自动钻井液切换系统和传扭动力卡瓦的配合，可实现钻井中拆卸、接装单根时钻井液不间断循环，有效避免因钻井液静置、沉砂过多导致的钻孔安全问题。

Abstract:

During drilling operations， circulation of drilling fluid has to be stopped in make-up and break-up of drill rods， which will cause the cuttings to settle downhole and the equivalent circulation density （ECD） of the drilling fluid to fluctuate； thus affecting the borehole safety. In order to avoid the above situation， the concept of uninterrupted drilling fluid circulation drilling technology is proposed. Drilling fluid is diverted through a continuous circulation system （CCS） or continuous circulation joint （CCJ）， by-passing the section of the drill pipes being worked to maintain mud circulation in the well， and stabilizing the equivalent circulation density （ECD） of drilling fluid. According to the technical principle， an automatic drilling fluid uninterrupted circulation wellhead is proposed. Through the cooperation of back-up tongs， the automatic drilling fluid switching system and torque-transfer power slips， uninterrupted circulation of drilling fluid can be realized during the disassembly and assembly of single drill rods in drilling to avoid effectively the drilling safety problems caused by drilling fluid standstill and excessive settlement of cuttings .