RTP pipe selection for a gathering system starts with the line, not the product. Reinforced thermoplastic pipe (RTP) is a strong option for many onshore flowlines, produced-water lines and injection lines, but it is not the default answer for every segment between a wellhead and a station. You save weeks when the enquiry says which line, which fluid, which pressure and temperature cycle and which tie-in ends, instead of “please quote RTP pipe, 4 inch, 5 km.”
This page helps you decide whether RTP belongs on a given gathering line and what to send so the quotes you get back can be compared. If you still need the basics (the three-layer construction, how RTP differs from GRE and TCP, and what API 15S language means), read RTP Pipe for Oilfield Service: What Reinforced Thermoplastic Pipe Is and How to Spec It first. This article picks up where that one stops: the fit decision for each line in a gathering network.
Who this page is for
- Production and facilities engineers sorting a gathering network into lines where RTP fits, lines where steel stays, and lines that need another non-metallic path.
- EPC and project teams turning a field layout into a line schedule that a pipe supplier can price without guessing.
- Procurement engineers who need quotes for the same configuration, fittings and documents, not a list of per-metre prices for different products.
Think in line segments, not in one pipe order
A gathering system is rarely one duty. A single field can have oil flowlines from wells to a manifold, a trunk line to the station, produced-water lines back to injection wells and maybe a gas line. Each one has its own fluid, pressure, temperature and route. RTP may fit three of them and be the wrong choice for the fourth.
Before you ask for prices, split the network into segments and fill in these fields for each one.
| Segment field | What to capture | Why it matters for RTP |
|---|---|---|
| Line function | Well flowline, manifold-to-station trunk, produced-water transfer, water injection, gas line, other | Liner choice, permeation checks and end fittings depend on the duty |
| From / to | Wellhead, manifold, station, injection well, existing steel line | Sets the tie-in ends and which interfaces belong in scope |
| Length and route | Length, terrain, crossings, burial or surface lay, elevation changes | Decides spool lengths, number of joints and the installation method |
| Fluid | Water chemistry, oil, gas fraction, CO₂ or H₂S notes, solids, treating chemicals | The liner has to be compatible with the whole fluid, including chemicals you dose |
| Pressure | Design pressure, normal operating pressure, surges, shut-in, pressure cycles | Ratings belong to a full configuration, not to the word “RTP” |
| Temperature | Normal, maximum and minimum, including upsets and ambient extremes | Liner and reinforcement limits change with temperature |
| Flow | Required flow rate or bore, not only nominal size | Hydraulic bore drives the size, and outside diameter drives the spool |
| Existing assets | Steel lines being replaced or rehabilitated, valves and flanges staying in place | Changes the transitions and fittings you need |
When RTP usually fits a gathering line
Lean toward RTP for a segment when most of these are true:
- Corrosion is driving steel line failures or treatment cost. The CNPS product page lists corrosion among the reasons to consider RTP, and it also says suitability for gas, sour exposure, chemicals or high temperature can’t be assumed from the material name. Check the offered liner and reinforcement against your actual water and gas analysis, including CO₂, H₂S and dosed chemicals.
- The line is long and continuous. Long reel lengths can reduce field joints and field assembly, provided the route, road access and reels allow it (see point 6).
- The duty is one the product page names. The CNPS product page lists gathering, water service and injection among the possible oilfield routes, when the exact product is qualified for the medium and operating envelope. Produced-water and injection lines are often the clearest fit.
- Your pressure and temperature sit well inside the offered configuration’s qualified envelope. Capability depends on the exact liner, reinforcement (polymer fibre, glass, aramid, steel or another qualified construction), cover, end fittings and size, and the word “RTP” doesn’t prove a rating by itself. Ask for the qualified pressure-temperature relationship for your size and fittings, not a single headline rating.
- Installation speed matters. Fewer joints and long continuous lengths can shorten the field schedule where rights of way and crews are limited. Tell the supplier whether the line will be buried, surface-laid or pulled through a conduit.
- You can plan around reels. Road access, reel size, bend radius and pull limits suit spooled pipe on the route.
Field check: if you can’t yet say what fluid, pressure cycle and temperature a segment will see over its life, settle that first. An RTP quote built on a guess often has to be redone when the real data arrives.
When steel or another path usually wins first
| Situation | Lean toward first | Why RTP is secondary |
|---|---|---|
| Pressure, temperature or size is near or past the qualified envelope of the offered configuration | Steel or a configuration that the supplier engineers and qualifies for the duty | Don’t stretch a rating in an email |
| Gas-rich line with frequent pressure cycling or fast blowdown, and no permeation or decompression data yet | Engineering review first | The liner choice and venting design need data, not a label |
| Offshore, subsea or dynamic riser service | API 17J unbonded flexible pipe or another offshore design | Offshore use may bring project and regulatory requirements beyond the public API 15S scope |
| Rigid, above-ground piping inside a station, or many fittings in a short run | Steel or rigid fiberglass (GRE/FRP) line pipe | Spoolable pipe pays off over distance, not in tight plant piping |
| Existing steel line that only needs an internal corrosion barrier | Steel with an HDPE lining tube | Keeps the steel pressure body and adds a liner |
| Short run where the main question is cost per metre against carbon steel | A lifecycle cost comparison | RTP has to win on installed and lifecycle cost, not on price per metre |
For offshore and deepwater flowlines, see API 17J Flexible Pipes for Deepwater Projects. For lining an existing steel line, see API 15LE HDPE Lining Tubes: When PE Line Pipe Fits Oilfield Gathering Service. For a rigid composite line, see How to Spec GRE/FRP Line Pipe from Pressure, Temperature, and Medium. For the cost side against steel, see RTP vs Carbon Steel Pipe: 5 Dimensions That Actually Matter (with 10-Year TCO Math).
Keep the spoolable and non-metallic scopes separate
Several pipe families can show up on the same gathering project. Each is its own RFQ object with its own standard and acceptance checks.
| Family | What it is | Where it usually belongs |
|---|---|---|
| RTP | Thermoplastic liner, reinforcement layer and thermoplastic jacket, spooled | Onshore flowlines, gathering, water and injection lines |
| TCP | Thermoplastic composite pipe; construction and bonding vary by maker | Read the maker’s defined construction; don’t assume RTP data applies |
| API 17J flexible pipe | Unbonded flexible pipe with metallic layers | Offshore flowlines, risers and jumpers |
| PE-lined steel | Steel line with an HDPE lining tube | Rehabilitating or protecting steel lines |
| GRE/FRP line pipe | Rigid filament-wound fiberglass, jointed | Rigid lines, plant piping, fiberglass line pipe standards |
If the RTP versus TCP question is still open, see RTP vs TCP Pipe: Key Differences.
Gathering-service checks that change the RTP answer
These are the points that most often turn a “yes, RTP” into “yes, but a different configuration,” or into “no”:
- Gas content and permeation. Gas passes through thermoplastic liners over time. Wet or multiphase lines with a gas fraction need the liner and the venting design checked for permeation, and for fast depressurisation if the line is blown down.
- Pressure cycling. Lines that cycle on and off, or see surges at well start-up, need the rating checked against cycling, not only static pressure.
- Treating chemicals. Corrosion inhibitors, scale inhibitors, demulsifiers and cleaning chemicals reach the liner too. List what you dose and at what point.
- Solids and pigging. Sand or scale changes wear and cleaning plans. Say whether the line will be pigged, and confirm the bore and fittings allow it.
- Tie-ins and transitions. End fittings, couplings and the joint to steel valves and flanges are part of the pressure-containing system. Size them with the pipe, not after it.
- Repairs and later tie-ins. Ask how a damaged section is repaired and how a future well is tied in, so the network can grow.
For a step-by-step version of these checks applied to flowlines and injection lines, the CNPS catalogue site has How to Choose RTP Pipe for Oil and Gas Flowlines and Injection Lines.
RFQ fields for an RTP gathering line
Send one line schedule with one row per segment, and these fields for each row. That gives every supplier the same basis, so the offers can be compared.
| RFQ field | What to send | Note |
|---|---|---|
| Segment ID and function | Line name, flowline, trunk, produced water, injection or gas | One row per segment |
| From / to and length | End points, route length, number of crossings | Add a route sketch if you have one |
| Fluid data | Water analysis, oil and gas fractions, CO₂ and H₂S notes, solids, dosed chemicals | Include the expected range over the field’s life |
| Pressure | Design, operating, surge and shut-in pressure, cycling pattern | State the pressure-class intent |
| Temperature | Normal, maximum and minimum fluid and ambient temperature | Include upsets |
| Bore or flow | Required inner diameter or flow rate | Lets the supplier size, not guess |
| Ends and interfaces | End fitting type, flanges, transitions to steel, valves | Name existing equipment that stays |
| Installation | Surface lay, trench, plough or insertion into an old line; reel and road limits | Affects spool length and accessories |
| Design life and inspection | Required service life, pigging, monitoring | Ask how the offer supports it |
| Documents | Datasheet, API 15S certificate copies and the sizes, pressure classes and end fittings they cover, test records, inspection and traceability plan | Ask for copies; don’t accept a certificate mention alone |
| Scope and delivery | Pipe, fittings, installation support, field testing, delivery point | Keeps quotes comparable |
CNPS supplies API 15S certified RTP. Ask for the certificate copies with the offer and check which products, sizes, pressure classes and end fittings they cover against your line schedule.
When you’re ready to match an offered configuration, start from the Reinforced Thermoplastic Pipe (RTP) product page.
Comparing RTP quotes
Price per metre only compares well when the offers describe the same thing. Before you rank quotes, check that each one states:
- the bore, reinforcement type and pressure rating at your design temperature for each segment;
- spool length and how many field joints the route will need;
- end fittings, couplings and transitions to steel, included or priced separately;
- the documents included, such as certificate copies and test records;
- installation support, field pressure testing and delivery terms.
FAQ
When is RTP a good fit for a gathering line?
When corrosion is driving steel failures or treatment cost, the route is long or awkward, and the line’s fluid, pressure and temperature sit well inside what the offered RTP configuration is rated for. Produced-water and injection lines are often the clearest fit.
Can RTP carry gas or multiphase flow?
It can be offered for lines with gas, but gas permeation through the liner and fast depressurisation need checking for the specific configuration. Send the gas fraction, pressure cycle and blowdown plan with your enquiry.
How do I check the pressure and temperature rating of an RTP offer?
Ask for the qualified pressure-temperature relationship of the exact configuration offered: liner, reinforcement, cover, size, pressure class and end fittings. The CNPS product page says the label “RTP” doesn’t prove a pressure or temperature rating by itself, so compare offers on that qualified envelope, not on one headline number.
Is RTP the right choice for offshore flowlines?
Usually not as a first choice. Offshore flowlines, risers and jumpers normally go to API 17J unbonded flexible pipe or another offshore design, and offshore RTP use may bring project and regulatory requirements beyond the public API 15S scope. This guide covers onshore gathering, transfer and injection lines.
Should I compare RTP with lined steel or fiberglass line pipe?
Yes, segment by segment. Lined steel suits rehabilitating an existing steel line, rigid fiberglass suits jointed and plant piping, and RTP suits long spooled runs. A mixed network often uses more than one.
What should I send to get a useful RTP quote?
Send a line schedule with one row per segment: function, end points, length, fluid data, pressure and temperature, bore or flow, ends and interfaces, installation method, design life and the documents you need, such as API 15S certificate copies. The RFQ table above lists each field.
Talk to an engineer before the RFQ goes out
If you’re not sure which of your gathering lines suit RTP, send the field layout, fluid data and pressure and temperature data to our team. We’ll tell you which segments make sense for RTP and what the offer should cover. Talk to an Engineer or email sales@cnps.com.
