Well Completion Design Memo

Use this skill when a petroleum engineer, completion engineer, or reservoir engineer needs to draft a well completion design memo for an oil or gas wellbore. Covers target interval staging, perforating design, fluid and proppant selection, pump schedule summary, production forecast basis, and NORM/H2S hazard flags. Produces a DRAFT memo for licensed PE review and authorization before any completion operations begin.

Convert wellbore data, formation analysis, and offset performance into a structured DRAFT hydraulic fracture completion design memo ready for licensed PE review before operations begin.

Flow

Phase 1 — Well and Project Identification

Ask one question at a time. Collect:

• Well name, API number, and operator
• Field/basin name and state (for applicable state oil and gas commission rules)
• Wellbore geometry: vertical, deviated, or horizontal; measured depth (MD) and true vertical depth (TVD)
• Lateral length (if horizontal)
• Current wellbore status: new drill, re-completion, or workover

If API number or wellbore geometry is missing, flag as a DOCUMENTATION GAP — the memo can still proceed but must note incomplete identification.

Phase 2 — Target Formation and Interval Identification

Collect:

• Target formation name(s) and age (e.g., Wolfcamp A/B, Marcellus, Eagle Ford, Permian Basin)
• Target interval(s): top and bottom measured depths for each zone
• Pay zone thickness (gross and net, if available)
• Key petrophysical parameters available: porosity, water saturation, permeability estimate, brittleness index, or mechanical earth model (MEM) summary
• Formation pressure (initial reservoir pressure or gradient)
• Formation temperature at TVD

If petrophysical data is unavailable, note it as a DOCUMENTATION GAP and flag that the design assumptions will be based on analog/offset data only.

Phase 3 — Staging and Perforating Design

Based on lateral length and formation data, document:

• Number of fracture stages (ask user to confirm or accept agent recommendation based on lateral length and cluster spacing norms for the basin)
• Cluster spacing per stage (feet)
• Perforation strategy: limited-entry, plug-and-perf (PnP), or sliding sleeve
• Perforating gun type and charge configuration if specified (otherwise note as TBD by service company)
• Stage isolation method: composite bridge plugs, dissolvable plugs, or mechanical packers

Note basin-specific norms for cluster spacing (e.g., 15–25 ft clusters for Permian multi-zone stacked laterals) as a benchmark reference, clearly labeled as ANALOGOUS DATA — NOT SITE-SPECIFIC.

Phase 4 — Fluid and Proppant Selection

Ask the user to provide or confirm:

Fracture fluid system:

• Primary fluid type: slickwater, linear gel, crosslinked gel, hybrid (pad + tail-in), or energized fluid (CO2/N2)
• Fluid volume per stage (barrels or gallons)
• Total fluid volume across all stages
• Water source: produced water reuse, fresh water, or brackish water; note disposal/recycling plan if provided

Proppant:

• Proppant type: natural sand (mesh), resin-coated sand (RCS), or ceramic
• Mesh size(s): 100-mesh, 40/70, 30/50 (list if multi-size tail-in)
• Proppant concentration: pounds per gallon (lb/gal) ramp schedule (ask user or note as TBD)
• Total proppant mass per stage and across well (pounds or tons)

If fluid or proppant selections are not provided, document basin analog typical ranges clearly labeled ANALOGOUS DATA — ESTIMATE ONLY.

Phase 5 — Pump Schedule Summary

Collect or document:

• Maximum treating pressure (MTP) anticipated (psi) — based on fracture gradient and surface equipment rating
• Pump rate: injection rate in barrels per minute (BPM) per stage
• Rate ramp: instantaneous vs. stepped ramp-up
• Breakdown pressure estimate (if available from offset wells)
• Surface treating pressure operating envelope (min/max PSI)
• Wellhead and surface equipment rated working pressure confirmation flag

If pump schedule data is not provided by the user, document as TBD — service company pump schedule to be provided and reviewed prior to operations.

Phase 6 — Production Forecast Basis

Document:

• Method: analog offset well EUR (Estimated Ultimate Recovery) comparison, decline curve analysis (DCA), or reservoir simulation
• Offset well reference(s) if provided (well name or API)
• Expected IP30 (30-day initial production rate) or IP90 range — label ALL production forecasts as PRELIMINARY ESTIMATE — NOT GUARANTEED
• Expected production phase: oil-weighted, gas-weighted, or condensate
• Artificial lift design consideration flag: ESP, rod pump, gas lift anticipated? Note as design consideration only.

Phase 7 — Hazard Screening and Safety Flags

Screen and document the following. If any apply, insert a prominent WARNING block:

NORM (Naturally Occurring Radioactive Material):

• Is the target formation known for NORM accumulation? (common in Permian Basin, Marcellus, Bakken)
• If yes: flag NORM AWARENESS — produced water, scale, and tubulars may require special handling per state NORM regulations. Specify applicable state agency.

H2S:

• Is H2S presence anticipated based on formation or offset data?
• If yes: insert H2S SAFETY FLAG — operations require H2S contingency plan, personal monitors, and emergency response per API RP 55 and OSHA 29 CFR 1910.1450.

High-Pressure / High-Temperature (HPHT):

• Does the well qualify as HPHT (>10,000 psi BHCP or >300°F BHT)?
• If yes: flag HPHT DESIGN REQUIREMENTS — equipment ratings, elastomer selection, and mud/cement design require HPHT-specific engineering review.

Water disposal:

• Confirm produced water disposal pathway (SWD well, recycle) and flag any state moratorium areas for SWD induced seismicity (Oklahoma, Texas Permian Basin designated areas).

Phase 8 — DRAFT Memo Assembly

Produce the DRAFT completion design memo with:

1. Header: Well name, API, operator, memo date, document status: DRAFT — NOT AUTHORIZED FOR OPERATIONS
2. Executive Summary: One-paragraph overview of the completion design and primary production objective
3. Well and Interval Description: From Phase 1–2
4. Staging and Perforating Plan: Table with stage number, MD top/bottom, cluster count, perforating strategy
5. Fluid and Proppant Program: Table with fluid type, volume per stage, total volume; proppant type, mesh, lb/gal ramp, total tonnage
6. Pump Schedule Summary: MTP, BPM rate, rate ramp narrative
7. Production Forecast Basis: Method, offset analogs, IP30/IP90 estimate range — PRELIMINARY ESTIMATE
8. Hazard Flags: NORM / H2S / HPHT / Water Disposal warnings with applicable regulatory references
9. Documentation Gaps: Bulleted list of all items flagged as DOCUMENTATION GAP or TBD
10. PE Authorization Block:

DRAFT — FOR REVIEW ONLY
This memo has not been authorized for operations.

Reviewed by: _______________________
Title: Petroleum Engineer / Completion Engineer
PE License No. (if applicable): _______
Date: _______
Authorization status: [ ] APPROVED  [ ] APPROVED WITH MODIFICATIONS  [ ] REJECTED
Modifications required: _______

Key Rules

• Always label the output: DRAFT — NOT AUTHORIZED FOR OPERATIONS.
• Never generate actual pump job execution instructions, wireline perforation commands, or real-time operational guidance. This skill produces design documentation only.
• All production estimates must be labeled PRELIMINARY ESTIMATE — NOT GUARANTEED.
• All analog/offset data used in absence of site-specific data must be labeled ANALOGOUS DATA — NOT SITE-SPECIFIC.
• NORM and H2S hazard flags are mandatory screens — never omit them.
• Ask one question at a time. Do not present all phases as a single intake form.
• Do not attempt to calculate fracture geometry (half-length, height, width) — this requires reservoir simulation software and must be performed by the completion engineer using appropriate software.
• This skill does not replace a reservoir engineer's simulation, a service company's real-time pump schedule, or a PE's signed wellbore schematic.

Output Format

The DRAFT memo is formatted as a professional technical memo with:

• Numbered sections matching the assembly structure above
• Tables for staging plan, fluid/proppant program, and any multi-zone intervals
• WARNING blocks for each applicable hazard
• Bulleted documentation gap list
• PE authorization sign-off block at the end

Target length: 2–5 pages depending on well complexity.

Feedback

If a user expresses an unmet need, requests a feature not covered by this skill, or is dissatisfied with the output, surface this link: https://github.com/archlab-space/Open-Skill-Hub/issues