Welding flowline

By 803056

Date 10-02-2008 03:57

Let me display my ignorance. What is a flow line?

Al

By aevald

Date 10-02-2008 04:14

Thanks Al, I was wondering the same thing, hadn't heard that term before. Learning opportunity? Is this possibly a live gas line? Be interested to know. Best regards, Allan

By Fredspoppy (**)

Date 10-02-2008 13:33

Related to the offshore Oil & Gas industry, a "flowline" is the term for the portion of the pipeline, laying on the bottom of the ocean, that connects the wellhead, and associated subsea equipment, with the platform. The portion of the pipeline that rises up from the bottom of the ocean to the platform is called the "riser". The point where the pipeline leaves the bottom to go up to the platform is called the "touch down point". It is really some length of pipe, due to tidal and wave effects that cause the platform to move up and down.

The important difference between flowline, touchdown and riser is the required level of quality for the pipelines and welds connecting the individual joints. As the riser is hanging from the platform, it is subject to more dynamic actions and therefore weld quality requirements are higher. Likewise the pipe in the touchdown area is also subjected to dynamic actions. The platform may be in water depths of up to 10,000 feet (~2 miles).

Attached is a sketch for your info. I am not sure if this relates to your specific situation, but should be of interest.

By hogan

Date 10-02-2008 14:16

thanks

By 3.2 Inspector (***)

Date 10-02-2008 14:46

Thanks.

3.2

By aevald

Date 10-02-2008 18:16

Hello Fredspoppy, I'll certainly third that thank you. Always nice to expand those brain walls just a bit more. Best regards, Allan

By NMWELDING (**)

Date 10-02-2008 19:17

Flow lines are not only offshore but land based also. They run from the wellhead to the stock tanks or in some cases to treaters and then to stock tanks.

By aevald

Date 10-02-2008 19:44

Hello NMWELDING, thank you for that additional information and clarification. I'll be the first to thank you for the additional information, but likely not the last. Best regards, Allan

By 803056

Date 10-03-2008 01:16

Excellent reply.

Right after I asked the question and I happen to start reading my Pipeline Journal and guess what, they were writing about flowlines as well, but they didn't provide the excellent description or the diagram provided by Fredspoppy!

Thanks for the information. As you can see, I am not experienced in the technical aspects of line pipe or that particular industry that is so vital to our well being.

Thanks - Al

By 8898jsmit (*)

Date 10-04-2008 14:48

Sorry for not getting back sooner. Have been swamped w/ work lately. What I am refering to is basically what Fredspoppy drew out only on ground like NMWelding mentioned. It's the pipe that runs frome the well head to the tank battery/seperator location. I believe most of it is threaded together, but there are a few weld joints. I have a couple guys locally that may have done it or know someone else who has. Just thought I'd see what came up on here. I'll keep you posted.

By Fredspoppy (**)

Date 10-05-2008 04:16

Just to follow up, the fluids extracted from the wells go through the flowline/riser to the platform where it is "semi-processed" to separate oil and gas from the other constituents. This is similar to what happens with onshore oil production pipelines/facilities. The processed crude (now "sweet") and gas are transported to the shore via export pipelines that go from the platform back down an export riser and through subsea flowlines to the shore where they end up in some type of processing facility, e.g., refinery, gas processing plant, etc.

The only different situation from this would be with an FPSO (floating processing storage and offloading) structure (basically a tanker with a mini refinery onboard). The crude oil is normally transported onshore with shuttle tankers. There currently are no FPSO's in the Gulf, but the Cascade & Chinook project, currently under construction/fabrication, will be the first.

Offshore Oil & Gas production is quite interesting.

By OsageOil (*)

Date 10-10-2008 19:57

Jared,

New construction should be no problem. If you modify or repair a flowline, MAKE SURE the field operator or pumper has shut in the well and bled the line down. Even then be prepared for a little bit of fire as the flowline will contain anything that has been pumped up from bottom hole. This may include crude oil, gas, salt water, and in some parts of the country H2S which can be lethal all by itself.

Years ago flowlines were constructed of threaded steel line pipe by roustabouts or pipe gangs. Nowadays a lot of them are made of poly pipe (plastic) especially on smaller volume wells.

By 8898jsmit (*)

Date 10-11-2008 01:24

Thanks for the replies. I hope to talk to a guy over the weekend about this. I welded alot of pipe in trade school that was all done with a 6010 root and hot pass, followed by 7018 fill and cap. I presume this would be standard procedure on flowline as well?

Everything I have noticed around here is 2 3/8, primarily threaded together like you said OsageOil. Roustabouts all over the place. I imagine there is poly being used, just haven't noticed.

By OsageOil (*)

Date 10-11-2008 03:42

Jared,

The procedure you mentioned should work great and might even be overkill. Most flowlines I am familiar with are low pressure and not subject to a lot of stress other than they terrain they are laid on (usually on top of the ground). When they are welded, it is not unusual for them to be 6010 all the way out. It would be wise to check with other welders in your area to see if they follow a different procedure or if welders not available examine some welds and see if they have been capped with 7018. You might also post this question on "Shop Talk" as there is an oilfield welder named "Sourdough" who could provide guidance. I personally would have no problem going 6010 all the way out on flowlines in my part of the country.

By dbigkahunna (****)

Date 10-11-2008 20:46 Edited 10-12-2008 02:11

A lot of flow lines were(are) made of old well tubing. This pipe can be magnetized and cause problems welding. Look for bell and box ends as the connectors vs. a standard thread coupling.

By 8898jsmit (*)

Date 10-12-2008 00:16

Osageoil,

Thats kind of what I was wondering. If it is overkill. I have a call into a guy, haven't heard back yet. Thats a good idea about checking the cap.

dbigkahunna,
Building fence and such, I've only run into a few sticks that were magnetized enough to give me fits. Good point and duely noted though. It was pretty old pipe and in rough shape. If you would, define bell and box ends to make sure I understand you right.

Thanks

By dbigkahunna (****)

Date 10-12-2008 02:11

[deleted]

By 8898jsmit (*)

Date 10-12-2008 14:40

Gotcha. I guess I've seen it both ways.

By 1mancrew (**)

Date 10-12-2008 20:12

I've welded a lot of flow line here in weld county CO. for a few different outfits. The pipe is usually 2" and either .154 wall or .188 wall. Depending on the company, you may get a little heavier yet.

The way I do it is to have a cradle with a couple of rollers on it to carry the pipe on the side of the truck as I move along. Ideally I have two helpers with me. First one drives the truck from one joint to the next (this saves me from having to roll-up cable at every joint) while the other one helps me to align the pipe, and then wire wheel the passes and move tools and rod bucket to the next joint. I usually bead and hot-pass the whole line (6010 1/8" all the way out) and then keep only the driver to go back and cap the whole line. Seems to go faster this way.

Hope this helps a little. Let me know if I can be of any further assistance.
GH Wedman

By 8898jsmit (*)

Date 10-13-2008 02:37

GH,
Exactly what I needed to hear. Few questions though. It sounds like very little if any is actually threaded together, is this the case? Are the pipe ends pre beveled or do you have to grind a bevel? And if I could ever stop in on a job, that would be worth more than anything that could be typed out on here. My numbers in my signature If you are willing to let me "look over your shoulder".
Thanks

By 1mancrew (**)

Date 10-15-2008 01:32

Correct sir, very little threading, usually just where the roustabouts install valves, etc, and tie into the seperator.

To bevel the pipe I just use a small grinder. On thin wall pipe it takes almost no time at all to make a good bevel. I carry a porta-band to make my cuts at tie-ins. I've seen some guys use a chop saw but the porta-band is much easier to use. The roustabouts typically use a tubing cutter and the clean up is very time consuming.

GH Weidman

By 8898jsmit (*)

Date 10-15-2008 02:17

Thanks for sharing. One more thing though. Whats the going rate for this and hows it billed out,
hourly or by the ft.? Thanks again.

By 1mancrew (**)

Date 10-26-2008 00:16

Sorry for not getting back to you sooner. I went on vacation last week to NY to visit some family.

I bill $75/hr for welding flowline and for about everything else I do for that matter. The problem with billing by the foot is that if you have to wait on the roustabouts it costs you money. If you are billing by the hour it tends to motivate the crews to move a little faster.

GH Weidman

By 1mancrew (**)

Date 10-26-2008 00:22

Forgot to leave you my number.

(970) 301-2535.

By 8898jsmit (*)

Date 10-27-2008 14:12

Thanks for sharing. I've got more work than I can do right now, but I'll contact you if things slow down a bit.