In the WR500SE product information, the maximum drilling depth is listed as 500 m, with a borehole diameter of 140–350 mm. The same document also states: 'A 500-meter-class drilling depth does not mean every project needs to drill to the extreme depth; the actual construction depth should be determined based on aquifer location and local hydrological data.' This reminder deserves separate elaboration, because one of the most common mistakes in selection discussions is treating the equipment's capability ceiling directly as the target depth of the construction plan. For the same machine, 'how deep it can drill' and 'how deep this project should drill' are two separate judgments, with different reference materials, different questions answered, and different costs when errors occur.
What Each Judgment Is Based On
| Comparison Item | How Deep It Can Drill | How Deep It Should Drill |
|---|---|---|
| Question answered | Whether the equipment, with a given configuration, can complete this depth | To what depth this well must be drilled to meet water use goals |
| Main basis | Lifting force, rotary torque, drill pipe specifications, mast stroke, air supply configuration | Aquifer location, expected water yield, borehole diameter, well casing and pump specifications |
| Typical reference | Product parameter table and configuration list | Local hydrological data and well completion design |
| Manifestation of misjudgment | Drilling tools cannot handle the load, cuttings return cannot keep up, auxiliary time too long | Insufficient water yield after well completion, or well depth exceeds necessary range |
The relationship between the two is: equipment capability sets the depth ceiling, while hydrology and well completion design set the target depth for this specific well. The target depth must fall within the ceiling, but the ceiling itself cannot in turn determine the target depth.
Several Items in the WR500SE Material Directly Related to Depth Capability
By extracting the values in the material related to 'whether it can drill to a certain depth,' we can see that they constrain different stages respectively, rather than all pointing to the single number '500 meters.'
Lifting Force Supports the Drill String and Casing
The WR500SE is equipped with a 26 T lifting force. The material positions it as the capability for 500-meter-class drill pipe tripping, DTH hammer recovery, and partial casing operations, and explains that in deep holes, when diameter reduction, block falling, or sediment occurs, the resistance to pulling out the drill string increases rapidly. Therefore, lifting capacity should be treated as a normal operating margin, not the sole means of handling all downhole incidents. The same document also states that actual borehole diameter and well depth should be designed based on expected water yield, irrigation area, well casing, and pump specifications. The two statements point to different levels: lifting force constrains whether the drill string can be tripped smoothly, while well completion design constrains how long the hole needs to be.
6.6-Meter Single Feed Affects Auxiliary Time
The WR500SE has a single feed length of 6.6 m, which can be used directly with 6 m drill pipes. The material explains that for 400–500-meter-class boreholes, the more times pipes are added, the more noticeable the accumulated auxiliary time; a long-stroke structure can reduce the frequency of the power head returning and drill pipe connections. It should be noted here that a long stroke improves process efficiency at the same depth, but does not change the basis for judging 'how deep it should drill.' If a well only needs to be drilled to 200 meters based on hydrological conditions, the 6.6-meter stroke still reduces the number of pipe connections during those 200 meters, rather than pushing the project to drill the full 500 meters.
Torque and Rotation Speed Correspond to Borehole Section Conditions
The material gives a rotary torque of 7500–10000 N·m and a rotation speed of 45–130 r/min, and explains that harder rock formations and larger borehole diameters usually require higher torque and lower rotation speeds, while borehole sections with less resistance can use higher rotation speeds; actual parameters should be adjusted in real time based on the DTH hammer, drill bit, drill pipe, and cuttings return conditions. This parameter affects whether drilling can proceed smoothly given the borehole diameter and rock formation, not the well depth target itself.
Air Supply Configuration Varies with Borehole Diameter, Rock Formation, Hole Depth, and Altitude
When using DTH drilling, the material recommends a working air pressure of 1.7–3.5 MPa and an air consumption of 17–42 m³/min, and clearly states that when borehole diameter increases, rock formation hardens, hole depth increases, or altitude rises, a more sufficient air flow is required, and one should not only look at the rated pressure. For deep holes, whether cuttings discharge is continuous often becomes a limiting factor earlier than whether the drill bit can bite into the rock. Therefore, air supply configuration is an important condition on the 'how deep it can drill' side.
What Information Determines How Deep It Should Drill
In the applicable scenarios, the WR500SE material lists rural deep wells, farmland irrigation wells, industrial water wells, mining area water supply, and general medium-to-deep groundwater projects, and explains that 500-meter-class equipment provides 'greater construction margin,' suitable for areas where shallow aquifers are unstable, groundwater depth is large, or water demand is high. These statements all point to the same type of judgment basis, not equipment parameters.
- Aquifer location: The depth of the main water-producing layer determines where the well completion section is located. The screen pipe and sealing section should be set according to the aquifer location. In the section 'Aquifer and Strong Water Inrush Borehole Section,' the material requires recording the depth of the main water-producing layer.
- Expected water yield and water use scale: For farmland, orchard, and greenhouse projects, the borehole diameter and well depth should be designed based on expected water yield, irrigation area, well casing, and pump specifications, not based on the equipment's maximum capability.
- Well casing and pump specifications: The pump's installation depth and well casing size affect the well completion depth and borehole diameter, which in turn affect the choice of drilling tools and hole-forming process.
- Formation conditions: The material mentions that weathered layers, alternating soft and hard formations, and loose overburden layers require special treatment, such as using casing in unstable upper borehole sections and considering a mud system in advance when the loose layer is thick. These treatments add process steps, but likewise do not constitute a reason to 'drill the full 500 meters.'
Specific Manifestations of Treating the Ceiling as the Target
The misunderstanding is not in using 500-meter-class equipment, but in treating the number 500 as an input to the construction plan. Common manifestations include: writing 500 meters as the basis for meeting water yield requirements instead of separately explaining the aquifer depth; setting the well depth before expected water yield, well casing, and pump specifications are determined; expecting the efficiency advantage of the 6.6-meter long stroke to yield 'more drilled depth'; and, when shallow hydrological data is incomplete, using the equipment capability ceiling to replace verification of groundwater depth. The product material itself places the value of the long stroke on reducing pipe connections and places the 500-meter drilling depth on 'construction margin'; neither uses the depth ceiling as the target depth.
Parts Not Covered by the Material That Require Separate Confirmation
This article can only explain which values in the WR500SE material correspond to capability ceilings and which statements point to well completion design; it cannot be used to determine how deep any specific project should drill. The following matters are outside the scope of the existing material and need to be confirmed separately in conjunction with local hydrological data and well completion design: the actual burial depth and thickness of the main aquifer at the project site; the target water yield and corresponding borehole diameter, well casing, and pump specifications; after the well depth is determined, rechecking whether the 26 T lifting force, 7500–10000 N·m torque, and air supply configuration leave a normal operating margin; and the constraints of relocation and site conditions on the overall machine weight of approximately 9.5 T and dimensions of approximately 6150 × 2200 × 2600 mm. Before these conditions are verified, the drilling depth figure should not be used as a conclusion for selection or construction plans.