The reaming design includes reaming classification, reaming type selection, reaming drilling assembly, cleaning drilling assembly, bit pressure, torque, speed and mud flow rate, etc.
The classification of reaming mainly depends on the formation property, final hole diameter, drilling length, drilling capacity, mud pump capacity, drill pipe size and reaming type.
The choice of reamer mainly depends on the physical and mechanical properties of the strata.
At present, there are two types of reamer.One is suitable for general soil layer (soft reamers) and the other one for rock stratum in common use (Rock reamers/HDD rock reamers). Each type of reamer has a variety of structural shapes.
Among them, the reamer suitable for soil layer has common structural forms such as barrel reamer, fluted reamer,cutter reamer, step type reamer. And rock reamer has two common structural forms, namely roller cone cutter type and hob type.
The diameter of the final hole of the horizontal directional drilling pipeline crossing project is generally 1.2 ~ 1.5 times of the outer diameter of the pipeline, and the design diameter is generally reached by means of graded reaming. The number of grades mainly depends on the nature of the formation, equipment capacity and the selected drill pipe specification.
Large equipment capacity and high drill pipe strength reduce the number of grading according to the formation conditions to speed up the construction schedule.
The nozzle of the reamer is the outlet of the mud. Once it is blocked, it will cause the rise of ground pump pressure or the phenomenon of no mud, which is not conducive to the drilling of the reamer.
Abnormal torque and tension during reaming may be related to formation, cuttings accumulation, borehole collapse, interrupted mud circulation, excessive wear of reamer, etc.
In case of abnormality, it is an effective way to analyze and judge the condition in the hole.
After the completion of the first stage of reaming, if the torque is too large in the whole process of reaming, it may be caused by excessive drilling cuttings content in the hole. Before entering the next stage of reaming, a thorough cleaning is very beneficial to reduce the pressure of the next stage of reaming.
Please feel free to contact us if you have any other questions about rock reamers, HDD reamers, hole openers.