Differences between Rotary and Impact Water Well Drilling Rigs
Here are the differences between the rotary water well Drilling Rig and the impact water well drilling rig:
1. Working principle
Rotary water well drilling rig: It forms the well-bore by relying on the rotary motion of the drilling tool to break the rock formation. The power unit drives the rotary table through the transmission device, and the active drill pipe drives the drill bit to rotate and cut the rock formation. At the same time, mud circulation or compressed air is used to cool and lubricate the drill bit, and carry the cuttings out of the wellhead.
Impact water well drilling rig: It breaks the rock formation at the bottom of the well by making the drill bit impact the bottom of the well through the vertical reciprocating motion of the drilling tool. A winch is used to lift and lower the drilling tool through a steel wire rope, allowing the drill bit to impact the formation under its own weight, breaking the cuttings. Then, tools like a sand pump are used to remove the cuttings from the ground.
2. Applicable formations
Rotary water well drilling rig: It is suitable for soil layers, general sand layers, and loose formations where the diameter of the pebbles is smaller than the inner diameter of the drill pipe. The hydraulic power head type rotary drilling rig can also be used with a large drill bit to drill large-diameter water wells. The down-hole vibration rotary drilling rig can be used in relatively hard rock formations.
Impact water well drilling rig: It is suitable for various formations, especially in hard rock formations, where it has a better drilling effect. However, when drilling in loose formations, the wellbore wall is likely to collapse.
3. Drilling efficiency
Rotary water well drilling rig: The drilling speed is relatively fast, especially in soft soil layers and moderately hard formations. For example, the reverse circulation mud washing rotary table drilling rig can form a relatively high upward flow velocity, which gives it a stronger ability to discharge cuttings and pebbles, and its drilling speed is faster than that of the forward circulation.
Impact water well drilling rig: The drilling efficiency is relatively low because it breaks the rock formation through repeated impacts, and the removal of cuttings cannot be carried out simultaneously with the drilling operation. Although it can also drill in hard rock formations, the speed is slow.
4. Wellbore quality
Rotary water well drilling rig: The drilled well-bore is relatively regular, the well-bore wall is relatively smooth, and it is easier to control the well deviation, which is beneficial for subsequent operations such as lowering the well pipe and well washing.
Impact water well drilling rig: The shape of the well-bore may not be very regular, and the well-bore wall is relatively rough. There may be some deviations during the drilling process. But for some water wells with not particularly high requirements for well-bore quality, it can still meet the usage requirements.
5. Equipment structure and operation
Rotary water well drilling rig: The structure is relatively complex, consisting of parts such as the drilling device and the circulating mud washing device. The operation requires a certain level of technical expertise, and parameters such as the rotation speed of the drilling tool and the mud circulation need to be controlled. However, the degree of automation is relatively high, and the labor intensity is relatively low.
Impact water well drilling rig: The structure is simple, and there is no circulating mud washing system. But it requires manual operations such as frequently lifting and lowering the drilling tool and removing cuttings, which has a relatively high labor intensity and requires more experience from the operators.
6. Mud usage and environmental friendliness
Rotary water well drilling rig: The mud usage is relatively large, and a special mud pit is needed to store and treat the mud. If not handled properly, it may cause certain pollution to the environment. However, the rotary drilling rig using compressed air for well washing can reduce the use of mud.
Impact water well drilling rig: Generally, it does not require a large amount of mud circulation, and it has relatively less pollution to the environment. But during the drilling process, there may be some dust raising, and corresponding dust prevention measures need to be taken.
7. Equipment cost
Rotary water well drilling rig: The equipment cost is relatively high, especially for some rotary drilling rigs with advanced functions and high automation. However, due to its high drilling efficiency, in large-scale and long-term water well construction, the comprehensive cost may be relatively low.
Impact water well drilling rig: The equipment cost is relatively low, but its drilling efficiency is low. In the case of a long construction period, it may increase labor costs and other expenses, thus leading to an increase in the comprehensive cost.
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