| Well objective | Identify whether the job is for production, injection, testing, stimulation, or selective access to one or more intervals. | Sets the required interval coverage, shot distribution, selectivity, and whether multiple gun sections or staged operations are appropriate. | Confirm target zones, planned sequence, isolation requirements, and the completion design with the subsurface and well engineering teams. |
| Target interval and formation | Record interval tops and bases, formation type, expected heterogeneity, and available formation-strength or rock-mechanics data. | Influences perforation placement and the choice of charge performance characteristics. Formation and completion conditions affect actual penetration and hole quality. | Use representative formation and completion data where available; do not treat published or laboratory charge performance as a guaranteed downhole result. |
| Casing, liner, and completion geometry | Specify casing or liner size, weight, grade, wall thickness, connection details, tubing dimensions, and internal restrictions. | Determines the allowable gun outside diameter, clearance, conveyance arrangement, and whether the selected system can pass through the completion. | Check the latest well schematic, drift restrictions, nipples, safety valves, packers, and any changes made after the schematic was issued. |
| Gun size and configuration | Define the available internal clearance, desired shot density, gun length, and required coverage across the target interval. | Gun diameter, carrier design, charge size, phasing, and shot density must be considered together; increasing one design feature may constrain another. | Verify dimensions and performance against the specific gun-and-charge configuration, casing geometry, and operating conditions—not nominal size alone. |
| Well trajectory and conveyance | Provide measured depth, inclination, azimuth, dogleg severity, and expected friction or conveyance limits. | Helps determine whether tubing-conveyed deployment is suitable and whether the assembly can reach, correlate, and remain positioned at the target. | Review torque-and-drag or conveyance analysis as applicable, toolstring length, deviation survey quality, and contingency plans for movement or retrieval. |
| Pressure and temperature | Define expected downhole pressure and temperature during run-in, firing, and retrieval, including credible transient conditions. | Every gun, initiator, seal, and associated component must be qualified for the anticipated environment and the selected operating sequence. | Compare the complete system’s rated limits with the well program and operating envelope; account for uncertainty and applicable qualification requirements. |
| Wellbore fluids and environment | Document fluid type, density, solids, gas content, corrosive species, and expected fluid-level conditions. | Fluid conditions affect hydrostatic pressure, corrosion exposure, debris risk, and the pressure differential across the perforations. | Confirm fluid compatibility for exposed components and review well-control, displacement, and fluid-handling procedures. |
| Pressure condition at firing | Define the planned pressure relationship between the wellbore and formation at the time of perforating. | Underbalanced, balanced, or overbalanced conditions can produce different cleanup and formation-damage outcomes. The appropriate condition is reservoir- and operation-specific. | Set the pressure target through reservoir, completion, and well-control analysis. Do not apply a universal underbalance value to all wells. |
| Shot phasing and orientation | Specify the desired angular distribution of shots and any orientation requirements imposed by the completion or well objective. | Phasing affects the circumferential distribution of perforations and should be assessed alongside casing clearance, shot density, and the intended flow paths. | Check the selected configuration against completion restrictions, formation objectives, and any required correlation or orientation method. |
| Selective firing and interval control | Identify whether separate zones must be fired independently, in a planned sequence, or with selective isolation between intervals. | May require a suitable firing-system architecture, compartmentalized gun sections, and compatible isolation or sequencing equipment. | Review the firing sequence, barriers, arming and disarming procedures, and contingencies for misfire or incomplete firing. |
| Well-control and operational safety | Define pressure-control equipment, barrier status, operating limits, exclusion zones, and the approved explosives-handling plan. | TCP selection must be compatible with the pressure-control stack, conveyance equipment, and the approved sequence for running and firing. | Complete a job-specific risk assessment, barrier review, equipment inspection, and explosives and misfire response plan under applicable regulations and procedures. |
| Final design verification | Compile the well schematic, target data, completion details, pressure and temperature envelope, fluid program, and firing objectives. | Supports an integrated review of gun dimensions, charge configuration, conveyance, pressure condition, and expected perforation performance. | Obtain documented engineering review and confirm that the final equipment configuration matches the approved program and current well conditions. |
