| Well purpose | Domestic water supply, irrigation, livestock, monitoring, or geothermal use | Match the drilling method, bore diameter, casing, and completion tools to the required yield and intended use. | Estimate daily demand, required flow rate, water quality needs, and applicable local standards. |
| Target depth | Shallow wells may reach the water table; deeper wells may penetrate confined aquifers or consolidated rock. | Confirm the rig’s rated drilling depth, hoisting capacity, mast height, and compatibility with the planned drill-string length. | Review nearby well records, geological maps, and anticipated aquifer depth; allow for uncertainty in the final depth. |
| Soil and formation | Unconsolidated sand and gravel, clay, weathered material, or hard and fractured rock | Augers or rotary methods may suit some unconsolidated formations; rotary or down-the-hole hammer systems are commonly considered for competent rock. | Identify likely layers, formation stability, abrasiveness, and whether temporary casing or drilling fluid may be needed. |
| Groundwater conditions | Water-bearing layers can vary in depth, pressure, and permeability. | Select equipment that can safely manage groundwater inflow and support appropriate casing and well-screen installation. | Check known water levels, artesian potential, seasonal variation, and requirements for protecting aquifers from contamination. |
| Site access and terrain | Restricted yards, steep slopes, soft ground, remote locations, or overhead obstacles | Consider rig dimensions, transport method, ground pressure, setup footprint, and available working clearance. | Verify access routes, turning space, soil bearing capacity, overhead utilities, and safe equipment positioning. |
| Water and power availability | Remote sites may lack a reliable water source, grid power, or fuel access. | Plan for the rig’s power requirements, compressor or pump needs, fuel consumption, and any water-storage or recirculation system. | Confirm supply capacity, operating hours, delivery logistics, and the availability of suitable water for drilling operations. |
| Casing and borehole design | Casing diameter and materials depend on the well design, formation stability, and local regulations. | Ensure the rig can handle the planned casing diameter and length, and has compatible lifting and installation tools. | Specify bore diameter, screen placement, casing materials, and sanitary sealing requirements before mobilization. |
| Safety and compliance | Drilling involves rotating machinery, suspended loads, noise, dust, and potential contact with underground or overhead services. | Choose equipment with suitable guarding, emergency stops, stable setup features, and maintenance support. | Check permits, utility clearances, operator training, site-specific risk controls, and applicable well-construction rules. |