Replies to This Discussion

Permalink Reply by Les Bamburg on May 7, 2011 at 3:55

Bob, hydrogen sulfide (H2S) is an issue for pipelines because it can be highly corrosive in the presence of water.  Also, very high levels of H2S in natural gas can be hazardous and is known as poison gas when these higher levels are present.

 

Because of these issues natural gas transmission pipelines have established limits for the H2S content with the most common limit being 4 parts per million (ppm) [0.25 grain per 100 standard cubic feet].  Most of the gas produced in the southern areas of the Haynesville Shale play require treatment in an amine facility prior to delivery to the gas transmission pipeline. 

Permalink Reply by Bob Langerak on June 15, 2011 at 8:07

I am really new to this and trying to learn as much as I can, the well in my section has been shutoff again because of HS2. So is this now a doomed well or can the gas be treated to get within the specs needed for the pipeline. How is this done, is a new pipeline needed to route the gas to a treatment plant or does this need to be done at the wellhead somehow. The well is near Noble/Sardis so are there any treatment plants in this area (S4-t8-r12). Feelin kinda blue about this as my excitment of being a part of a producing well that is not producting is fading fast.

Permalink Reply by Pelican on June 29, 2011 at 12:57

CenterPoint has a treatment plant at Robeline and Clearlake for treating all of Shell's and EnCana's wells in De Soto and Sabine Parish.  It is up to the operator to make sure that the H2S meets their agreed upon contractual obligations before it enters the gathering pipeline.  Normally less than 50 ppm.

 

Permalink Reply by Henry on June 29, 2011 at 14:20

Pelican,

Can you explain how this works?  I'll try, and you correct me when/if I go wrong.  So every SWEPI/EnCana well has a pipe that leads to a small gathering line that only takes SWEPI/EnCana gas?  And these small SWEPI/EnCana gathering lines go to larger SWEPI/EnCana pipelines that all eventually lead to one of these two treating facilities?  Then, once treated, the gas is sold into some nearby big pipeline that takes it to market?  Is that how it works?

Permalink Reply by Pelican on June 30, 2011 at 1:25

CEFS usually pick the gas up at the wellhead. They nominate it to different transmission pipelines where CEFS delivers it for them. It then is treated to meet pipeline specs and delivered to various pipes.
Before the gas enters CEFS , the producer must meet what CEFS and the producer have contractually such as in the case of h2s - 50 ppm.

Permalink Reply by Les Bamburg on June 30, 2011 at 2:56

Henry, the CEFS gathering/treating systems were built primarily to serve EnCana/Shell but likely gather some other operator's gas production also.  Any non-EnCana/Shell interest in their operated units is probably handled through this system under marketing arrangements with EnCana and/or Shell.  See attached for diagram of CEFS gathering system. 

 

EnCana/Shell hold capacity on some of the downstream pipelines so the actually sales may occur closer to the market area.

Attachments:

• CEFS Haynesville Shale System.pdf, 959 KB

Permalink Reply by Bob Langerak on June 30, 2011 at 3:27

Hi everyone, I appreciate your info. Do they need a special pipe at the well to handle the sour gas? Sounds like they need to reduce the sour gas at the well head if that is the correct term, really new to this but learning fast. I have contacted Swepi several times and they tell me the well, 241012, is not producing but using Sonris I see monthly production which seems low, April was 40,000. So, will the production stay "low" because of not being able to allow a normal flow from the well? Not complaining because some gas is better than none. Just wondering if this level of production is what I should expect. Also Encana is doing an alternate well under or on top of this well, so thinking this is a good thing.

Permalink Reply by Les Bamburg on June 30, 2011 at 16:37

Bob, gathering systems are designed to handle certain levels of CO2 and H2S upstream of the gas treating facility.  I am not sure if the gathering line or treating capacity is the reason for Shell/EnCana keeping the well rate low.

Permalink Reply by Pelican on July 5, 2011 at 10:37

I have heard that the well has been shut in until Shell gets the H2S under control.

Permalink Reply by Bob Langerak on July 8, 2011 at 3:16

Hi, I am wondering how they get H2S under control? Do they need to run a different pipeline to the well. Is this a quick fix, I am thinking this will take a while or will they keep the well shut forever.

Permalink Reply by Pelican on July 12, 2011 at 8:55

CEFS does not put in extra gathering lines for this h2s problem. I wouldn't think anyone else would do this either. Shell uses Scavenger to treat this gas at the wellhead to get it down to 50 ppm before it can flow. CEFS would then treat it at one of their plant facilities to get it below 4 ppm before delivering to a transmission line.
Now the bad news. This well olympia minerals 4h-1 and 26h-1 have extremely high h2s. Have heard above 600 ppm. Don't know when or if they will ever be able to come back on.

Permalink Reply by Bob Langerak on July 12, 2011 at 9:33

Thanks for the news, I appreciate it even if bad news. They are planning to drill an alternate on this section 4-T8N-R12W. So why would they do an alternate well if the H2S is really high for the 4h-1 well?

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