TL;DR — Read Green Duo mud conditions and backflush scope together
For a Mission Green Duo piston enquiry, retain both the drilling-fluid condition and the words “for each piston” in NOV's backflush recommendation. The flyer paragraph recommends Green Duo for oil or synthetic based mud, and for water based mud at 11 lb/gal or over; it recommends backflush at 14 gal/min or greater for each piston. Its application chart also contains different water-based-mud boundary labels, so the paragraph alone must not become an unconditional selection rule. Confirm the applicable document and installed arrangement before treating these literature values as an operating requirement. NOV Fluid End Expendables, PDF pages 1–2.
Scope — Which Green Duo sources are being compared?
This article compares the Green Duo paragraph on PDF page 1 and the application chart on PDF page 2 of NOV's Fluid End Expendables flyer, copyright 2019, RigDoc 106841002 | 7952. The older Mission Drilling Solutions brochure repeats the paragraph and chart on PDF page 8, printed page 4; its PDF page 24 identifies copyright 2015 and D352004107-MKT-001 Rev.02, and describes the brochure as general information rather than a design document. Source checked on October 20, 2026, Los Angeles time. These dates and identifiers do not establish the latest applicable revision.
The focus is how to preserve the mud-condition wording, document discrepancies and per-piston flow scope in an enquiry record. Installed piston identity, backflush arrangement, measurement basis and current applicability remain unresolved. The record fields below are editorial guidance, not an OEM installation procedure, replacement approval or commissioning instruction. NOV Mission Drilling Solutions, PDF pages 8 and 24.
Which fluid does the Green Duo paragraph describe?
The oil, synthetic and water based mud statements describe the drilling mud being pumped. The cited paragraph describes Green Duo as a bonded dual durometer piston and recommends it for oil or synthetic based mud; its water based mud recommendation carries the condition 11 lb/gal or over. Keep that condition with the product name and source page rather than extending it to every water-based formulation. NOV Fluid End Expendables, PDF page 1.
Do not turn a drilling-mud recommendation into a recipe for the separate piston/liner backflush or cooling circuit. The paragraph supplies no such recipe. Fluid identity and operating conditions for an actual assembly require its applicable documentation. The older brochure repeats this wording; that repetition is a document cross-check, not independent service-test evidence. NOV Mission Drilling Solutions, PDF page 8.
Why do the paragraph and chart need a clarification note?
Because their boundary labels are not identical. The flyer's first chart panel has water-based-mud rows labelled >#10 and <#10; the next panel has >#11 and <#11. The prose instead says 11 lb/gal or over. A strict greater-than label does not itself include equality, and the #10 and #11 pairs must not be silently rewritten into one threshold. Both label pairs are visible in the original chart, not merely an extraction artefact. NOV Fluid End Expendables, PDF page 2.
The older brochure also places these differing labels with its Green Duo material. This article does not resolve which chart boundary is intended, convert the colour ratings into numerical limits, or approve a mud at the equality boundary. Record the exact wording and request written clarification for the identified piston and intended mud. NOV Mission Drilling Solutions, PDF page 8.
Does 14 gal/min mean the entire system supply?
No. The Green Duo paragraph attaches its recommendation of 14 gal/min or greater to each piston. A system supply figure alone does not establish flow at each piston, and visible spray is not a measured per-piston flow result. Retain the measurement location, method and circuit identity alongside any recorded value. These are evidence fields, not a new test procedure. NOV Fluid End Expendables, PDF page 1.
The paragraph prints gal/min without explicitly distinguishing the gallon convention. Preserve that source unit and request the applicable measurement basis before converting it. This article does not calculate a combined supply requirement, choose a nozzle or valve setting, or claim an installed circuit meets the recommendation. The brochure's matching paragraph retains the same per-piston scope. NOV Mission Drilling Solutions, PDF page 8.
Evidence checklist — What should the enquiry retain?
Keep source recommendations separate from actual equipment evidence. The following record structure is editorial guidance.
| Record item | Source or evidence to retain | Missing-evidence action |
|---|---|---|
| Pumped mud condition | Green Duo paragraph: oil or synthetic based mud; water based mud 11 lb/gal or over | Record actual mud class and density with its unit; request applicability confirmation |
| Chart boundary discrepancy | Original chart pairs >#10 / <#10 and >#11 / <#11, alongside the prose | Preserve both pairs and the equality wording; request written clarification |
| Backflush scope | Paragraph recommendation: 14 gal/min or greater for each piston | Identify circuit and measurement basis; do not substitute total supply or visible spray |
| Component and document identity | Piston reference, assembly/drawing revision and cited document pages | Mark unknown identity or current revision unresolved before selection |
- Record the full piston marking or reference and the assembly it belongs to; a green colour alone does not identify an approved replacement.
- Keep drilling-mud data separate from the backflush/cooling-circuit record.
- Preserve the exact source page, year, document identifier and unresolved chart discrepancy.
- Mark unmeasured flows and unconfirmed configurations as unknown. A completed enquiry record does not authorize operation.
FAQ
Does the Green Duo paragraph recommend every water-based mud?
No. Its water based mud recommendation says 11 lb/gal or over, while the chart has differing boundary labels that require clarification for the intended application.
Is 14 gal/min the quoted requirement for the whole pump?
No. The paragraph recommends 14 gal/min or greater for each piston; it does not establish a combined system supply or verify an installed circuit.
Can the chart's #10 and #11 labels be merged into one limit?
No. Preserve the differing original labels and the prose's equality wording, and request written clarification rather than inventing a single threshold.
Does the oil-based-mud recommendation specify the backflush fluid?
No. It describes the drilling mud being pumped and does not supply a backflush or cooling-fluid recipe for an installed assembly.
Sources and related links
- NOV Fluid End Expendables — PDF pages 1–2: Green Duo paragraph and application chart; copyright 2019, RigDoc 106841002 | 7952.
- NOV Mission Drilling Solutions — PDF page 8, printed page 4; PDF page 24: repeated paragraph/chart and general-information scope; copyright 2015, D352004107-MKT-001 Rev.02.
- NOV 12-P-160 equipment catalogue: equipment navigation only; this link does not confirm Green Duo fitment to a particular pump.
- Type P liner spray inspection record: a separate observation-record topic, not a Green Duo selection or flow qualification.
- Type P piston/liner coolant-system record: separate circuit-document scope; it does not resolve these Green Duo chart labels.
Next step — Submit identity, mud and circuit evidence
Use the Green Duo documentation enquiry contact to provide the piston reference, assembly/drawing revision, intended drilling-mud class and density, backflush-circuit identity and any existing measurement record with units. Attach the conflicting source excerpts and identify what remains unknown. Request applicable documentation and clarification; this article makes no stock, delivery-time, service-life or performance promise.