BH25 Final Bore Diameter and Pump Passage
The nominal diameter of the drill bit does not fully describe the space available in a completed well. A pump installation needs the as-built passage, including casing, joints, restrictions, alignment and associated equipment. The drilling and pump-selection records should therefore meet at a clearly documented completion drawing.
Separate planned and as-built dimensions
Record the designed hole and casing arrangement, then retain the actual installation record. Show changes in diameter or construction by depth. Identify how dimensions were established and where they remain uncertain.
A catalogue dimension for a casing product is not a complete record of an installed well. Likewise, a drilling log that states only bit size cannot establish that an intended pump assembly will pass through every relevant interval.
Review the complete pump assembly
Obtain the proposed pump and motor dimensions together with cable, guards, connectors, rising main and any other installed items. Ask the pump specialist to confirm the required clearances and installation method using the actual assembly and well geometry.
Do not choose a universal clearance from a generic article. Manufacturer requirements, installation conditions and maintenance access must be considered. The procurement record should identify the approved combination, not merely the pump’s nominal size.
Account for future access
Ask how the pump will be installed, removed and inspected. Identify any completion detail that could restrict later work. These questions should be resolved before ordering equipment, particularly where the as-built record differs from the original plan.
Well-construction guidance recognises alignment and construction dimensions as relevant subjects. The available NGWA scope description supports including them in the review, but the actual acceptance criteria require the appropriate design and installation references.
Connect geometry with hydraulic selection
Passing through the well is one requirement; meeting the selected flow and head is another. The pump proposal should address both. A physically suitable pump can still be mismatched to the operating duty, and an attractive pump curve does not establish installation compatibility.
Retain the pumping-test record, selected operating rate, water-level assumptions and system-head assessment with the installation drawing. Any unresolved geometry should be settled before the equipment selection is treated as final.
Prepare the installation brief: collect the as-built well record and proposed equipment dimensions. Use Well Testing and Production Duty for the hydraulic decision and the project enquiry brief for compressor-related support requirements.
Related pages: Casing and Unstable Formation Planning · Well Completion Cleaning and Development · Borewell Yield Testing and Production Duty