Started:
2022-05-03 18:24:16
Last activity:
2022-05-09 15:10:27
Topics:
Distributed Acoustic Sensing
Marco Olivieri
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one
telecom company deployment that will connect a town to a village (about 8
km long). We expect to use it for seismic monitoring purposes with DAS. As
far as we know they will use a standard method i.e. dig an 8 km long
trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct
besides the telecom one or to have it buried directly to the ground (out of
pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those
interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
We have been offered to deploy our own fiber‐optic cable besides one
telecom company deployment that will connect a town to a village (about 8
km long). We expect to use it for seismic monitoring purposes with DAS. As
far as we know they will use a standard method i.e. dig an 8 km long
trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct
besides the telecom one or to have it buried directly to the ground (out of
pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those
interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-
This seems like a controversial topic! I personally find a tight buffered
cable and direct burial provides the best mechanical coupling to the soil
and thus the highest fidelity strain measurements. Please see these two
manuscripts currently being reviewed that detail this type of installation
and show example cables.
https://www.preprints.org/manuscript/202204.0268/v1
https://arxiv.org/abs/2202.04779
Best,
Peter
On Tue, May 3, 2022 at 9:26 AM Marco Olivieri (via IRIS) <
das-bounce<at>lists.ds.iris.edu> wrote:
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one
telecom company deployment that will connect a town to a village (about 8
km long). We expect to use it for seismic monitoring purposes with DAS. As
far as we know they will use a standard method i.e. dig an 8 km long
trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct
besides the telecom one or to have it buried directly to the ground (out of
pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those
interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
----------------------
Distributed Acoustic Sensing - For more information on the Distribution
Acoustic Sensing Research Coordination Network, please go to:
https://www.iris.edu/hq/initiatives/das_rcn
Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe:
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-
Agree on the "out of the conduit" if possible. Only potential downside
is mechanical damage which is more likely without the PVC. We tried 4
cables using direct burial including fully SS encapsulated, an
anti-rodent cable (with steel tape surrounding the gel-filled core),
and 2 types of tactical. The responses were surprisingly similar in
the 5-25 Hz range but the light tactical was much simpler to deploy
(lighter, no shape memory). We have yet to have major rodent problems
with our cables but I'm sure there will be a first at some point!
https://www.nature.com/articles/s41598-017-11986-4.pdf
We did have one difficult experiment involving fiber in double-walled
conduit and I wasn't thrilled by the data quality (although it was
processable).
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2018GL081195
Cheers - J.
On Tue, May 3, 2022 at 1:02 PM Peter Hubbard (via IRIS)
<das-bounce<at>lists.ds.iris.edu> wrote:
This seems like a controversial topic! I personally find a tight buffered cable and direct burial provides the best mechanical coupling to the soil and thus the highest fidelity strain measurements. Please see these two manuscripts currently being reviewed that detail this type of installation and show example cables.
--
https://www.preprints.org/manuscript/202204.0268/v1
https://arxiv.org/abs/2202.04779
Best,
Peter
On Tue, May 3, 2022 at 9:26 AM Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu> wrote:
Dear All,
----------------------
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
----------------------
Distributed Acoustic Sensing - For more information on the Distribution Acoustic Sensing Research Coordination Network, please go to: https://www.iris.edu/hq/initiatives/das_rcn
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Dr. Jonathan Ajo-Franklin
ja62<at>rice.edu
JBAjo-Franklin<at>lbl.gov
Professor (Geophysics)
Dept. of Earth, Environmental, and Planetary Sciences
Rice University, MS-126
6100 Main Street, Houston, TX 77005
Visiting Faculty, Geophysics Dept.
Energy Geosciences Division
Earth and Environmental Sciences Area
Lawrence Berkeley National Laboratory
#1 Cyclotron Road, MS 74R0120
Berkeley, CA 94720
Cell : (510)-735-4350
-
Hello all.
I share the vast majority of the comments of the speakers who have
intervened in the debate before me.
The experience of more than 30 years in fiber optic installations of our
parent company, FIBERCOM, and the knowledge that we at Aragón Photonics
Labs have acquired in DAS sensing infrastructures the last 10 years have
allowed us to develop a cable specially designed for this use.
I attach a product sheet for reference (sorry for being in Spanish).
This cable is designed for sensing, but can of course also be used for
telecommunications, although the small number of fibres does not make it
particularly suitable for trunking.
There are several manufacturers offering similar cables, some developed
specifically for DAS and others simply ruggedised cables. It is important
to analyse the details of the characteristics of each cable to see if they
are really the best choice for DAS.
In our opinion, there are three main aspects to take into account when
choosing the cable and the installation technique:
- It is preferable for the cable to be directly buried rather than
inside a tube. A burial of between 20 and 50 cm is more than sufficient,
but the depth is usually determined by the conditions of the environment
(soil material, human and other activities in the vicinity, etc.)
- The cable that is directly buried must be resistant to external
aggressions (rodents, humans, etc.). Metal reinforcements are usually the
best option (strips, layers, rods...), the stronger the better.
- The loose tube is the best choice to protect the optical fibre in
these circumstances, but it is very important that this tube has
thixotropic gel so that the mechanical waves can propagate effectively to
the fibre from the outside of the cable.
I hope this information will be useful to you.
Best regards.
Francisco M. López
*BC*
[image: logo APL]
[image: icono APL]
f.lopez<at>aragonphotonics.com [image: icono correo]
+34 976 359 972 <+34976359972> [image: icono telefono]
www.aragonphotonics.com [image: icono web]
Prado 5, local 50009 Zaragoza, Spain https://goo.gl/maps/ftAc7DQmHFfBE7vL8
[image: icono direccion]
El mar, 3 may 2022 a las 20:47, Jonathan Ajo-Franklin (via IRIS) (<
das-bounce<at>lists.ds.iris.edu>) escribió:
Agree on the "out of the conduit" if possible. Only potential downside
is mechanical damage which is more likely without the PVC. We tried 4
cables using direct burial including fully SS encapsulated, an
anti-rodent cable (with steel tape surrounding the gel-filled core),
and 2 types of tactical. The responses were surprisingly similar in
the 5-25 Hz range but the light tactical was much simpler to deploy
(lighter, no shape memory). We have yet to have major rodent problems
with our cables but I'm sure there will be a first at some point!
https://www.nature.com/articles/s41598-017-11986-4.pdf
We did have one difficult experiment involving fiber in double-walled
conduit and I wasn't thrilled by the data quality (although it was
processable).
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2018GL081195
Cheers - J.
On Tue, May 3, 2022 at 1:02 PM Peter Hubbard (via IRIS)
<das-bounce<at>lists.ds.iris.edu> wrote:
This seems like a controversial topic! I personally find a tight
buffered cable and direct burial provides the best mechanical coupling to
the soil and thus the highest fidelity strain measurements. Please see
these two manuscripts currently being reviewed that detail this type of
installation and show example cables.
https://www.preprints.org/manuscript/202204.0268/v1
das-bounce<at>lists.ds.iris.edu> wrote:
https://arxiv.org/abs/2202.04779
Best,
Peter
On Tue, May 3, 2022 at 9:26 AM Marco Olivieri (via IRIS) <
telecom company deployment that will connect a town to a village (about 8Dear All,
We have been offered to deploy our own fiber‐optic cable besides one
km long). We expect to use it for seismic monitoring purposes with DAS. As
far as we know they will use a standard method i.e. dig an 8 km long
trench, bury a pvc duct and insert the fiber‐optic cable in it.
besides the telecom one or to have it buried directly to the ground (out ofThe question is: Would it be better to insert our cable in the pvc duct
pipe)? Do you know any paper or technical report that discusses this task?
interested.Please respond to me directly and I will compile responses for those
Acoustic Sensing Research Coordination Network, please go to:Any hint would be appreciated.
Thanks
Marco Olivieri
----------------------
Distributed Acoustic Sensing - For more information on the Distribution
https://www.iris.edu/hq/initiatives/das_rcn
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--
Dr. Jonathan Ajo-Franklin
ja62<at>rice.edu
JBAjo-Franklin<at>lbl.gov
Professor (Geophysics)
Dept. of Earth, Environmental, and Planetary Sciences
Rice University, MS-126
6100 Main Street, Houston, TX 77005
Visiting Faculty, Geophysics Dept.
Energy Geosciences Division
Earth and Environmental Sciences Area
Lawrence Berkeley National Laboratory
#1 Cyclotron Road, MS 74R0120
Berkeley, CA 94720
Cell : (510)-735-4350
----------------------
Distributed Acoustic Sensing - For more information on the Distribution
Acoustic Sensing Research Coordination Network, please go to:
https://www.iris.edu/hq/initiatives/das_rcn
Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe:
das-unsubscribe<at>lists.ds.iris.edu
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Attachments
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Out of the duct.
I have only seen one instance where duct improved DAS signal and this was a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Androidhttps://aka.ms/AAb9ysg
________________________________
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 3, 2022 5:25:36 PM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-- This email was sent to you by someone outside of ASN. Be careful of attachments and links. Report suspicious emails to cybersecurity<at>asn.com --
-
Hi Marco:
In order the maximize coupling to the ground we always did a direct bury of a gel filled fiber. If you place it in conduit you may get a situation in which the fiber is suspended in air and vibrates like a guitar string in the conduit introducing severe noise. If you can place you conduit and then backfill a bit you should have better coupling….
I’d recommend reaching out to Dan Costley at US Army ERDC for publications and reports on best practices.
Good luck!
Best,
Jason
—————————-
Jason McKenna
(601) 618 4969
On May 3, 2022, at 11:46 AM, Daniel DANSKIN (via IRIS) <das-bounce<at>lists.ds.iris.edu> wrote:
Out of the duct.
I have only seen one instance where duct improved DAS signal and this was a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Android
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 3, 2022 5:25:36 PM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-- This email was sent to you by someone outside of ASN. Be careful of attachments and links. Report suspicious emails to cybersecurity<at>asn.com --
----------------------
Distributed Acoustic Sensing - For more information on the Distribution Acoustic Sensing Research Coordination Network, please go to: https://www.iris.edu/hq/initiatives/das_rcn
Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe: das-unsubscribe<at>lists.ds.iris.edu
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Update subscription preferences at http://ds.iris.edu/account/profile/
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Hi all,
Pick a cable which won't be cut by rodents.
-Neal
________________________________
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on behalf of Daniel DANSKIN (via IRIS) <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 3, 2022 11:44 AM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Out of the duct.
I have only seen one instance where duct improved DAS signal and this was a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Androidhttps://aka.ms/AAb9ysg
________________________________
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 3, 2022 5:25:36 PM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-- This email was sent to you by someone outside of ASN. Be careful of attachments and links. Report suspicious emails to cybersecurity<at>asn.com --
-
Well, that is easier said than done!! But braided steel overlay works well, as does low cost “flat drop” cable from AFL that has fiberglass strength elements, which most rodents don’t like.
Not sure if they are producing single mode flat drop tho.
Dr. Scott Tyler
Foundation Professor
University of Nevada, Reno
styler<at>unr.edu<styler<at>unr.edu>
http://scotttylerhydro.com/
http://www.ctemps.orghttp://www.ctemps.org/
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 03, 2022 9:56 AM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Hi all,
Pick a cable which won't be cut by rodents.
-Neal
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of Daniel DANSKIN (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 11:44 AM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Out of the duct.
I have only seen one instance where duct improved DAS signal and this was a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Androidhttps://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Faka.ms%2FAAb9ysg&data=05%7C01%7Cstyler%40unr.edu%7C438e90070a734226412c08da2d26bfbe%7C523b4bfc0ebd4c03b2b96f6a17fd31d8%7C0%7C1%7C637871941696779787%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=V3P%2BZQC3WqReNdWCNApLEZ53pfn70Ad4QCIng0pjg9Q%3D&reserved=0
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 5:25:36 PM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-- This email was sent to you by someone outside of ASN. Be careful of attachments and links. Report suspicious emails to cybersecurity<at>asn.com<cybersecurity<at>asn.com> --
-
All,
I agree with Dan that good coupling to the soil and rock is essential. I agree with Neal that protecting from rodents is also essential. The key words are "StrataJac® encapsulation" and "rodent deterrent additive". Please find below some information about the 9000 meters of cable deployed at Brady Hot Springs, Nevada as part of the PoroTomo project. If this information is helpful, then please cite the appropriate references.
Best,
Kurt
The (horizontal) surface cable is a ruggedized military type cable that is rodent resistant with acrylate-coated fibers rated to 85°C, as shown in Figure 15. The cable was laid into the trench as five separate cable lengths and spliced together using “direct-bury” splice enclosures. The cable was tested for fiber integrity and the trench backfilled using a skid-steer loader.
[cid:26099de5-2f11-4b9c-b9c1-fb2160b8b4c5]
Typical optical cables contain several bundled fibers within outer protective layers. Two types of cable were used at Brady. The trenched cable was a tight-buffered construction with a polymer jacket, the borehole cable was a fiber in metal tube (FIMT) based construction. Each cable contained several of both types of fiber: multimode (MM), used for DTS, and singlemode (SM), used for DAS. For each installation a pair of MM fibers were joined at the far end with a u-bend termination to allow a double-ended DTS configuration. The upper right photo in Figure 1 shows the splicebox at the terminus of the trench. A similar spliced pair of SM fibers were used for the borehole DAS installation (DASV) which was recorded over an interval that included both the wellhead and the turnaround splice with about 10 extra channels at each end (an aid to matching DTS and DAS channels with well geometry).
Miller, Douglas E., Thomas Coleman, Xiangfang Zeng, Jeremy R. Patterson, Elena C. Reinisch, Michael A. Cardiff, Herbert F. Wang, Dante Fratta, Whitney Trainor-Guitton, and Clifford H. Thurber. "DAS and DTS at Brady Hot Springs: Observations about coupling and coupled interpretations." In Proceedings of the 43rd Workshop on Geothermal Reservoir Engineering, Stanford, CA, USA, pp. 12-14. 2018. http://erlweb.mit.edu/sites/default/files/Miller%20DAT%20and%20DTS%20at.pdfhttp://secure-web.cisco.com/1inWmo1EpKWa2g9M1iVVx4Kudgwh7HZP5341qhSC945n3BX7YnWRZCQZFVc8u1kQA7i3FK-eaDQn0QYI3du80a7vtKK5TQGiq6AoDO1NzXYK-n3TFvzdM_JtKl2qnN7buve2COjei7-GjNNdISZ8N0055fyNdbZHhvibjiQXHOpanaRHaF9LNF_fihq4ZLpMpVgB3Ow1qq-tnG55MM6BnZW6I30sN8dVoMlX-UPQCKl-Ix1nMC815uA4OwxzxdU35q4FASCRXEps3HozEgYKQLRU1tEYv1zpM33IgiztXKvJMMUWfUaegbhYhEmGx8-Ow/http%3A%2F%2Ferlweb.mit.edu%2Fsites%2Fdefault%2Ffiles%2FMiller%2520DAT%2520and%2520DTS%2520at.pdf
The (horizontal) surface cable is a ruggedized polyurethane jacketed military type cable that is rodent-resistant with acrylate-coated fibers rated to 85°C. To install the cable, we dug a trench approximately 100 cm deep using a Ditch Witch-style trencher (Figure 4.12). The bottom surface of the trench was leveled and smoothed using a tool attached to the trencher and manually using a hoe. The trenching process took approximately two weeks. The cable was laid into the trench as five separate cable lengths spliced together using “direct-bury” enclosures.
[cid:1df461d7-b929-4644-99da-2a0d7184f55b]
https://www.osti.gov/biblio/1499141https://secure-web.cisco.com/1SIBGmReqQEnNWsqs5b1fzNuaZgcYdozKx6gnqYLRobaB3mSikpNYmj0AHpptfFjx8uumnH7ZagAgednTa6AvfeuQo3yZGpz55YKCeVVd3Uv_EDbC1EYVc_BdzWKq2vCRTXO3oW6IlzUeitqszkqQVk9M89vvfxAWHkCgKivxcOGkKwrsgKnTYlUS-zdMJHpiNKkuAk1rXMyX9v0UV8VTUdtE7wvBubuMJ7trx-5DamDXf0Q1kdOIqPykCE5UIHgKApRlyo18jwJ8CvGRc0Y1PfIqSw1SlZB-6hWU1m4TOqaLB2a9fFpv2lxjl2nQIPz7/https%3A%2F%2Fwww.osti.gov%2Fbiblio%2F1499141
Feigl, K. L., and L. M. Parker (2019), PoroTomo Final Technical Report: Poroelastic Tomography by Adjoint Inverse Modeling of Data from Seismology, Geodesy, and Hydrology, Medium: ED; Size: 176 p. pp, ; Univ. of Wisconsin, Madison, WI (United States). https://www.osti.gov/servlets/purl/1499141
Kurt Feigl (he/him/his)
Professor
Department of Geoscience
University of Wisconsin-Madison
1215 West Dayton Street
Madison, WI
53706 USA
http://geoscience.wisc.edu/feigl
________________________________
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on behalf of NEAL E LORD (via IRIS) <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 3, 2022 11:55
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Hi all,
Pick a cable which won't be cut by rodents.
-Neal
________________________________
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on behalf of Daniel DANSKIN (via IRIS) <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 3, 2022 11:44 AM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Out of the duct.
I have only seen one instance where duct improved DAS signal and this was a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Androidhttps://aka.ms/AAb9ysg
________________________________
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu>
Sent: Tuesday, May 3, 2022 5:25:36 PM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-- This email was sent to you by someone outside of ASN. Be careful of attachments and links. Report suspicious emails to cybersecurity<at>asn.com --
-
Interrogator monitors the fiber extremely well so it’s all about coupling fiber to your signal of interest and then separating that signal from nuisance signal. However, one guy’s nuisance is another guy’s key to interpretation of the mixed response.
You may want to consider backfilling (cable outside PVC) with a slurry (e.g. bentonite) that will harden to enhance cable to ground coupling. PVC conduit will be a guide of some sort for signal that will couple to ground & cable.
DTS acquired simultaneously with DAS from the same cable will show heterogeneity of soil & soil-cable coupling. DTS is better resolved spatially (less resolved temporally) than DAS.
Douglas E Miller
Research Affiliate
Department of Earth, Atmospheric and Planetary Sciences, MIT
77 Massachusetts Ave 54-211
demiller<at>mit.edu<demiller<at>mit.edu>
203 733 6751 (cell)
http://www.mit.edu/~demiller
On May 3, 2022, at 1:56 PM, Kurt Feigl (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> wrote:
All,
I agree with Dan that good coupling to the soil and rock is essential. I agree with Neal that protecting from rodents is also essential. The key words are "StrataJac® encapsulation" and "rodent deterrent additive". Please find below some information about the 9000 meters of cable deployed at Brady Hot Springs, Nevada as part of the PoroTomo project. If this information is helpful, then please cite the appropriate references.
Best,
Kurt
The (horizontal) surface cable is a ruggedized military type cable that is rodent resistant with acrylate-coated fibers rated to 85°C, as shown in Figure 15. The cable was laid into the trench as five separate cable lengths and spliced together using “direct-bury” splice enclosures. The cable was tested for fiber integrity and the trench backfilled using a skid-steer loader.
<image.png>
Typical optical cables contain several bundled fibers within outer protective layers. Two types of cable were used at Brady. The trenched cable was a tight-buffered construction with a polymer jacket, the borehole cable was a fiber in metal tube (FIMT) based construction. Each cable contained several of both types of fiber: multimode (MM), used for DTS, and singlemode (SM), used for DAS. For each installation a pair of MM fibers were joined at the far end with a u-bend termination to allow a double-ended DTS configuration. The upper right photo in Figure 1 shows the splicebox at the terminus of the trench. A similar spliced pair of SM fibers were used for the borehole DAS installation (DASV) which was recorded over an interval that included both the wellhead and the turnaround splice with about 10 extra channels at each end (an aid to matching DTS and DAS channels with well geometry).
Miller, Douglas E., Thomas Coleman, Xiangfang Zeng, Jeremy R. Patterson, Elena C. Reinisch, Michael A. Cardiff, Herbert F. Wang, Dante Fratta, Whitney Trainor-Guitton, and Clifford H. Thurber. "DAS and DTS at Brady Hot Springs: Observations about coupling and coupled interpretations." In Proceedings of the 43rd Workshop on Geothermal Reservoir Engineering, Stanford, CA, USA, pp. 12-14. 2018. http://erlweb.mit.edu/sites/default/files/Miller%20DAT%20and%20DTS%20at.pdfhttp://secure-web.cisco.com/1inWmo1EpKWa2g9M1iVVx4Kudgwh7HZP5341qhSC945n3BX7YnWRZCQZFVc8u1kQA7i3FK-eaDQn0QYI3du80a7vtKK5TQGiq6AoDO1NzXYK-n3TFvzdM_JtKl2qnN7buve2COjei7-GjNNdISZ8N0055fyNdbZHhvibjiQXHOpanaRHaF9LNF_fihq4ZLpMpVgB3Ow1qq-tnG55MM6BnZW6I30sN8dVoMlX-UPQCKl-Ix1nMC815uA4OwxzxdU35q4FASCRXEps3HozEgYKQLRU1tEYv1zpM33IgiztXKvJMMUWfUaegbhYhEmGx8-Ow/http%3A%2F%2Ferlweb.mit.edu%2Fsites%2Fdefault%2Ffiles%2FMiller%2520DAT%2520and%2520DTS%2520at.pdf
The (horizontal) surface cable is a ruggedized polyurethane jacketed military type cable that is rodent-resistant with acrylate-coated fibers rated to 85°C. To install the cable, we dug a trench approximately 100 cm deep using a Ditch Witch-style trencher (Figure 4.12). The bottom surface of the trench was leveled and smoothed using a tool attached to the trencher and manually using a hoe. The trenching process took approximately two weeks. The cable was laid into the trench as five separate cable lengths spliced together using “direct-bury” enclosures.
<image.png>
https://www.osti.gov/biblio/1499141https://secure-web.cisco.com/1SIBGmReqQEnNWsqs5b1fzNuaZgcYdozKx6gnqYLRobaB3mSikpNYmj0AHpptfFjx8uumnH7ZagAgednTa6AvfeuQo3yZGpz55YKCeVVd3Uv_EDbC1EYVc_BdzWKq2vCRTXO3oW6IlzUeitqszkqQVk9M89vvfxAWHkCgKivxcOGkKwrsgKnTYlUS-zdMJHpiNKkuAk1rXMyX9v0UV8VTUdtE7wvBubuMJ7trx-5DamDXf0Q1kdOIqPykCE5UIHgKApRlyo18jwJ8CvGRc0Y1PfIqSw1SlZB-6hWU1m4TOqaLB2a9fFpv2lxjl2nQIPz7/https%3A%2F%2Fwww.osti.gov%2Fbiblio%2F1499141
Feigl, K. L., and L. M. Parker (2019), PoroTomo Final Technical Report: Poroelastic Tomography by Adjoint Inverse Modeling of Data from Seismology, Geodesy, and Hydrology, Medium: ED; Size: 176 p. pp, ; Univ. of Wisconsin, Madison, WI (United States). https://www.osti.gov/servlets/purl/1499141
Kurt Feigl (he/him/his)
Professor
Department of Geoscience
University of Wisconsin-Madison
1215 West Dayton Street
Madison, WI
53706 USA
http://geoscience.wisc.edu/feigl
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of NEAL E LORD (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 11:55
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Hi all,
Pick a cable which won't be cut by rodents.
-Neal
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of Daniel DANSKIN (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 11:44 AM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Out of the duct.
I have only seen one instance where duct improved DAS signal and this was a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Androidhttps://aka.ms/AAb9ysg
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 5:25:36 PM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-- This email was sent to you by someone outside of ASN. Be careful of attachments and links. Report suspicious emails to cybersecurity<at>asn.com<cybersecurity<at>asn.com> --
----------------------
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Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe: das-unsubscribe<at>lists.ds.iris.edu<das-unsubscribe<at>lists.ds.iris.edu>
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-
Doug et al.,
Thanks for the interesting discussion of buried DAS fiber. I take exception
to the idea of using a backfill material that will harden to enhance ground
coupling. My experience is that you want to minimize acoustic impedance
contrast between the native formation and the DAS cable backfill material.
The simplest way to achieve that is to use native materials, unless they
could be damaging to the cable. In that case a small amount of sand can be
used to surround the cable and then covered with native compacted
materials.
Best Regards,
Barry
_____________________________________________
Barry Freifeld, Ph.D.
Class VI Solutions, Inc.
711 Jean St.
Oakland, CA 94610
cell (510) 520-2618
bmfreifeld<at>classvisolutions.com
On Tue, May 3, 2022 at 8:59 PM Douglas E Miller (via IRIS) <
das-bounce<at>lists.ds.iris.edu> wrote:
Interrogator monitors the fiber extremely well so it’s all about coupling
fiber to your signal of interest and then separating that signal from
nuisance signal. However, one guy’s nuisance is another guy’s key to
interpretation of the mixed response.
You may want to consider backfilling (cable outside PVC) with a slurry
(e.g. bentonite) that will harden to enhance cable to ground coupling. PVC
conduit will be a guide of some sort for signal that will couple to ground
& cable.
DTS acquired simultaneously with DAS from the same cable will show
heterogeneity of soil & soil-cable coupling. DTS is better resolved
spatially (less resolved temporally) than DAS.
*Douglas E Miller Research Affiliate Department of Earth, Atmospheric
and Planetary Sciences, MIT 77 Massachusetts Ave 54-211 demiller<at>mit.edu
<demiller<at>mit.edu> 203 733 6751 (cell) http://www.mit.edu/~demiller
http://www.mit.edu/~demiller*
On May 3, 2022, at 1:56 PM, Kurt Feigl (via IRIS) <
das-bounce<at>lists.ds.iris.edu> wrote:
All,
I agree with Dan that good coupling to the soil and rock is essential. I
agree with Neal that protecting from rodents is also essential. The key
words are "StrataJac® encapsulation" and "rodent deterrent additive".
Please find below some information about the 9000 meters of cable deployed
at Brady Hot Springs, Nevada as part of the PoroTomo project. If this
information is helpful, then please cite the appropriate references.
Best,
Kurt
The (horizontal) surface cable is a ruggedized military type cable that is
rodent resistant with acrylate-coated fibers rated to 85°C, as shown in
Figure 15. The cable was laid into the trench as five separate cable
lengths and spliced together using “direct-bury” splice enclosures. The
cable was tested for fiber integrity and the trench backfilled using a
skid-steer loader.
<image.png>
Typical optical cables contain several bundled fibers within outer
protective layers. Two types of cable were used at Brady.* The trenched
cable was a tight-buffered construction with a polymer jacket,* the
borehole cable was a fiber in metal tube (FIMT) based construction. *Each
cable contained several of both types of fiber: *multimode (MM), used for
DTS, and *singlemode (SM), used for DAS.* For each installation a pair of
MM fibers were joined at the far end with a u-bend termination to allow a
double-ended DTS configuration. The upper right photo in Figure 1 shows the
splicebox at the terminus of the trench. A similar spliced pair of SM
fibers were used for the borehole DAS installation (DASV) which was
recorded over an interval that included both the wellhead and the
turnaround splice with about 10 extra channels at each end (an aid to
matching DTS and DAS channels with well geometry).
Miller, Douglas E., Thomas Coleman, Xiangfang Zeng, Jeremy R. Patterson,
Elena C. Reinisch, Michael A. Cardiff, Herbert F. Wang, Dante Fratta,
Whitney Trainor-Guitton, and Clifford H. Thurber. "DAS and DTS at Brady Hot
Springs: Observations about coupling and coupled interpretations." In *Proceedings
of the 43rd Workshop on Geothermal Reservoir Engineering, Stanford, CA, USA*,
pp. 12-14. 2018.
http://erlweb.mit.edu/sites/default/files/Miller%20DAT%20and%20DTS%20at.pdf
http://secure-web.cisco.com/1inWmo1EpKWa2g9M1iVVx4Kudgwh7HZP5341qhSC945n3BX7YnWRZCQZFVc8u1kQA7i3FK-eaDQn0QYI3du80a7vtKK5TQGiq6AoDO1NzXYK-n3TFvzdM_JtKl2qnN7buve2COjei7-GjNNdISZ8N0055fyNdbZHhvibjiQXHOpanaRHaF9LNF_fihq4ZLpMpVgB3Ow1qq-tnG55MM6BnZW6I30sN8dVoMlX-UPQCKl-Ix1nMC815uA4OwxzxdU35q4FASCRXEps3HozEgYKQLRU1tEYv1zpM33IgiztXKvJMMUWfUaegbhYhEmGx8-Ow/http%3A%2F%2Ferlweb.mit.edu%2Fsites%2Fdefault%2Ffiles%2FMiller%2520DAT%2520and%2520DTS%2520at.pdf
The (horizontal) surface cable is a ruggedized polyurethane jacketed
military type cable that is rodent-resistant with acrylate-coated fibers
rated to 85°C. To install the cable, we dug a trench approximately 100 cm
deep using a Ditch Witch-style trencher (Figure 4.12). The bottom surface
of the trench was leveled and smoothed using a tool attached to the
trencher and manually using a hoe. The trenching process took approximately
two weeks. The cable was laid into the trench as five separate cable
lengths spliced together using “direct-bury” enclosures.
<image.png>
https://www.osti.gov/biblio/1499141
https://secure-web.cisco.com/1SIBGmReqQEnNWsqs5b1fzNuaZgcYdozKx6gnqYLRobaB3mSikpNYmj0AHpptfFjx8uumnH7ZagAgednTa6AvfeuQo3yZGpz55YKCeVVd3Uv_EDbC1EYVc_BdzWKq2vCRTXO3oW6IlzUeitqszkqQVk9M89vvfxAWHkCgKivxcOGkKwrsgKnTYlUS-zdMJHpiNKkuAk1rXMyX9v0UV8VTUdtE7wvBubuMJ7trx-5DamDXf0Q1kdOIqPykCE5UIHgKApRlyo18jwJ8CvGRc0Y1PfIqSw1SlZB-6hWU1m4TOqaLB2a9fFpv2lxjl2nQIPz7/https%3A%2F%2Fwww.osti.gov%2Fbiblio%2F1499141
Feigl, K. L., and L. M. Parker (2019), PoroTomo Final Technical Report:
Poroelastic Tomography by Adjoint Inverse Modeling of Data from Seismology,
Geodesy, and Hydrology, Medium: ED; Size: 176 p. pp, ; Univ. of Wisconsin,
Madison, WI (United States). https://www.osti.gov/servlets/purl/1499141
Kurt Feigl (he/him/his)
Professor
Department of Geoscience
University of Wisconsin-Madison
1215 West Dayton Street
Madison, WI
53706 USA
http://geoscience.wisc.edu/feigl
------------------------------
*From:* das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on
behalf of NEAL E LORD (via IRIS) <das-bounce<at>lists.ds.iris.edu>
*Sent:* Tuesday, May 3, 2022 11:55
*To:* Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
*Subject:* Re: [IRIS][das] Fiber‐Optic Cable deployment
Hi all,
Pick a cable which won't be cut by rodents.
-Neal
------------------------------
*From:* das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on
behalf of Daniel DANSKIN (via IRIS) <das-bounce<at>lists.ds.iris.edu>
*Sent:* Tuesday, May 3, 2022 11:44 AM
*To:* Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
*Subject:* Re: [IRIS][das] Fiber‐Optic Cable deployment
Out of the duct.
I have only seen one instance where duct improved DAS signal and this was
a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Android https://aka.ms/AAb9ysg
------------------------------
*From:* das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu> on
behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu>
*Sent:* Tuesday, May 3, 2022 5:25:36 PM
*To:* Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
*Subject:* [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one
telecom company deployment that will connect a town to a village (about 8
km long). We expect to use it for seismic monitoring purposes with DAS. As
far as we know they will use a standard method i.e. dig an 8 km long
trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct
besides the telecom one or to have it buried directly to the ground (out of
pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those
interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
-- This email was sent to you by someone outside of ASN. Be careful of
attachments and links. Report suspicious emails to cybersecurity<at>asn.com
--
----------------------
Distributed Acoustic Sensing - For more information on the Distribution
Acoustic Sensing Research Coordination Network, please go to:
https://www.iris.edu/hq/initiatives/das_rcn
Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe:
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Acoustic Sensing Research Coordination Network, please go to:
https://www.iris.edu/hq/initiatives/das_rcn
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-
Barry,
Your point is well taken.
I wonder what published comparisons of backfill strategy are now available.
I imagine that in specific cases such as the one in question a comparison of two or three alternatives could be made at the site prior to the main installation.
Keep in mind that the impact of impedance contrast is sensitive to the volume of contrasting material as well as to the slip condition at all material interfaces (including those within the cable).
Best regards,
Doug
Douglas E Miller
Research Affiliate
Department of Earth, Atmospheric and Planetary Sciences, MIT
77 Massachusetts Ave 54-211
demiller<at>mit.edu<demiller<at>mit.edu>
203 733 6751 (cell)
http://www.mit.edu/~demiller
On May 4, 2022, at 12:20 AM, Barry Freifeld (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> wrote:
Doug et al.,
Thanks for the interesting discussion of buried DAS fiber. I take exception to the idea of using a backfill material that will harden to enhance ground coupling. My experience is that you want to minimize acoustic impedance contrast between the native formation and the DAS cable backfill material. The simplest way to achieve that is to use native materials, unless they could be damaging to the cable. In that case a small amount of sand can be used to surround the cable and then covered with native compacted materials.
Best Regards,
Barry
_____________________________________________
Barry Freifeld, Ph.D.
Class VI Solutions, Inc.
711 Jean St.
Oakland, CA 94610
cell (510) 520-2618
bmfreifeld<at>classvisolutions.com<bmfreifeld<at>classvisolutions.com>
On Tue, May 3, 2022 at 8:59 PM Douglas E Miller (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> wrote:
Interrogator monitors the fiber extremely well so it’s all about coupling fiber to your signal of interest and then separating that signal from nuisance signal. However, one guy’s nuisance is another guy’s key to interpretation of the mixed response.
You may want to consider backfilling (cable outside PVC) with a slurry (e.g. bentonite) that will harden to enhance cable to ground coupling. PVC conduit will be a guide of some sort for signal that will couple to ground & cable.
DTS acquired simultaneously with DAS from the same cable will show heterogeneity of soil & soil-cable coupling. DTS is better resolved spatially (less resolved temporally) than DAS.
Douglas E Miller
Research Affiliate
Department of Earth, Atmospheric and Planetary Sciences, MIT
77 Massachusetts Ave 54-211
demiller<at>mit.edu<demiller<at>mit.edu>
203 733 6751 (cell)
http://www.mit.edu/~demiller
On May 3, 2022, at 1:56 PM, Kurt Feigl (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> wrote:
All,
I agree with Dan that good coupling to the soil and rock is essential. I agree with Neal that protecting from rodents is also essential. The key words are "StrataJac® encapsulation" and "rodent deterrent additive". Please find below some information about the 9000 meters of cable deployed at Brady Hot Springs, Nevada as part of the PoroTomo project. If this information is helpful, then please cite the appropriate references.
Best,
Kurt
The (horizontal) surface cable is a ruggedized military type cable that is rodent resistant with acrylate-coated fibers rated to 85°C, as shown in Figure 15. The cable was laid into the trench as five separate cable lengths and spliced together using “direct-bury” splice enclosures. The cable was tested for fiber integrity and the trench backfilled using a skid-steer loader.
<image.png>
Typical optical cables contain several bundled fibers within outer protective layers. Two types of cable were used at Brady. The trenched cable was a tight-buffered construction with a polymer jacket, the borehole cable was a fiber in metal tube (FIMT) based construction. Each cable contained several of both types of fiber: multimode (MM), used for DTS, and singlemode (SM), used for DAS. For each installation a pair of MM fibers were joined at the far end with a u-bend termination to allow a double-ended DTS configuration. The upper right photo in Figure 1 shows the splicebox at the terminus of the trench. A similar spliced pair of SM fibers were used for the borehole DAS installation (DASV) which was recorded over an interval that included both the wellhead and the turnaround splice with about 10 extra channels at each end (an aid to matching DTS and DAS channels with well geometry).
Miller, Douglas E., Thomas Coleman, Xiangfang Zeng, Jeremy R. Patterson, Elena C. Reinisch, Michael A. Cardiff, Herbert F. Wang, Dante Fratta, Whitney Trainor-Guitton, and Clifford H. Thurber. "DAS and DTS at Brady Hot Springs: Observations about coupling and coupled interpretations." In Proceedings of the 43rd Workshop on Geothermal Reservoir Engineering, Stanford, CA, USA, pp. 12-14. 2018. http://erlweb.mit.edu/sites/default/files/Miller%20DAT%20and%20DTS%20at.pdfhttp://secure-web.cisco.com/1inWmo1EpKWa2g9M1iVVx4Kudgwh7HZP5341qhSC945n3BX7YnWRZCQZFVc8u1kQA7i3FK-eaDQn0QYI3du80a7vtKK5TQGiq6AoDO1NzXYK-n3TFvzdM_JtKl2qnN7buve2COjei7-GjNNdISZ8N0055fyNdbZHhvibjiQXHOpanaRHaF9LNF_fihq4ZLpMpVgB3Ow1qq-tnG55MM6BnZW6I30sN8dVoMlX-UPQCKl-Ix1nMC815uA4OwxzxdU35q4FASCRXEps3HozEgYKQLRU1tEYv1zpM33IgiztXKvJMMUWfUaegbhYhEmGx8-Ow/http%3A%2F%2Ferlweb.mit.edu%2Fsites%2Fdefault%2Ffiles%2FMiller%2520DAT%2520and%2520DTS%2520at.pdf
The (horizontal) surface cable is a ruggedized polyurethane jacketed military type cable that is rodent-resistant with acrylate-coated fibers rated to 85°C. To install the cable, we dug a trench approximately 100 cm deep using a Ditch Witch-style trencher (Figure 4.12). The bottom surface of the trench was leveled and smoothed using a tool attached to the trencher and manually using a hoe. The trenching process took approximately two weeks. The cable was laid into the trench as five separate cable lengths spliced together using “direct-bury” enclosures.
<image.png>
https://www.osti.gov/biblio/1499141https://secure-web.cisco.com/1SIBGmReqQEnNWsqs5b1fzNuaZgcYdozKx6gnqYLRobaB3mSikpNYmj0AHpptfFjx8uumnH7ZagAgednTa6AvfeuQo3yZGpz55YKCeVVd3Uv_EDbC1EYVc_BdzWKq2vCRTXO3oW6IlzUeitqszkqQVk9M89vvfxAWHkCgKivxcOGkKwrsgKnTYlUS-zdMJHpiNKkuAk1rXMyX9v0UV8VTUdtE7wvBubuMJ7trx-5DamDXf0Q1kdOIqPykCE5UIHgKApRlyo18jwJ8CvGRc0Y1PfIqSw1SlZB-6hWU1m4TOqaLB2a9fFpv2lxjl2nQIPz7/https%3A%2F%2Fwww.osti.gov%2Fbiblio%2F1499141
Feigl, K. L., and L. M. Parker (2019), PoroTomo Final Technical Report: Poroelastic Tomography by Adjoint Inverse Modeling of Data from Seismology, Geodesy, and Hydrology, Medium: ED; Size: 176 p. pp, ; Univ. of Wisconsin, Madison, WI (United States). https://www.osti.gov/servlets/purl/1499141
Kurt Feigl (he/him/his)
Professor
Department of Geoscience
University of Wisconsin-Madison
1215 West Dayton Street
Madison, WI
53706 USA
http://geoscience.wisc.edu/feigl
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of NEAL E LORD (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 11:55
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Hi all,
Pick a cable which won't be cut by rodents.
-Neal
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of Daniel DANSKIN (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 11:44 AM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: Re: [IRIS][das] Fiber‐Optic Cable deployment
Out of the duct.
I have only seen one instance where duct improved DAS signal and this was a waterlogged duct!
All other duct installations have poor signal compared to direct bury.
I'm sure every other vendor will say the same.
Dan
Get Outlook for Androidhttps://aka.ms/AAb9ysg
________________________________
From: das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu> <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>> on behalf of Marco Olivieri (via IRIS) <das-bounce<at>lists.ds.iris.edu<das-bounce<at>lists.ds.iris.edu>>
Sent: Tuesday, May 3, 2022 5:25:36 PM
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu<das<at>lists.ds.iris.edu>>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
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Ciao Marco,
We have some experience of setting up conventional telecom cable
(multimode and single mode fibres) in volcanic scoria (Etna volcano,
Italy). We could perform quite convincing studies as shown in
https://se.copernicus.org/articles/12/993/2021/ and
https://www.nature.com/articles/s41467-022-29184-w
In both cases, cables were dug in 10 cm to 30 cm depth directly in the
scoria, without any duct or anything, to increase coupling.
Thanks all for interesting discussion.
All best,
Philippe
On 5/3/22 18:25, Marco Olivieri (via IRIS) wrote:
Dear All,
--
We have been offered to deploy our own fiber‐optic cable besides one
telecom company deployment that will connect a town to a village
(about 8 km long). We expect to use it for seismic monitoring purposes
with DAS. As far as we know they will use a standard method i.e. dig
an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable
in it.
The question is: Would it be better to insert our cable in the pvc
duct besides the telecom one or to have it buried directly to the
ground (out of pipe)? Do you know any paper or technical report that
discusses this task?
Please respond to me directly and I will compile responses for those
interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
----------------------
Distributed Acoustic Sensing - For more information on the Distribution Acoustic Sensing Research Coordination Network, please go to: https://www.iris.edu/hq/initiatives/das_rcn
Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe: das-unsubscribe<at>lists.ds.iris.edu
Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/
Dr. Philippe Jousset
-
EGU Seismology Division President
-
Helmholtz-Zentrum Potsdam
Deutsches GeoForschungsZentrum GFZ
Near-surface Geophysics
Telegrafenberg, 14473 Potsdam, Germany
Tel.: +49 (0) 331 288 1299
Email: pjousset<at>gfz-potsdam.de
http://www.gfz-potsdam.de/
-
Thank you, Marco, for starting off such a vigorous discussion. I've given
all timezones a fair shot at this and kept responses open, but I would like
to encourage folks to respond directly to one another now.
Given that this is a topic of interest, however, please get in touch with
me directly at kasey<at>iris.edu if you would like to be involved in a
discussion or panel on fiber emplacement techniques in the near future.
Cheers,
Kasey
On Tue, May 3, 2022 at 12:29 PM Marco Olivieri (via IRIS) <
das-bounce<at>lists.ds.iris.edu> wrote:
Dear All,
--
We have been offered to deploy our own fiber‐optic cable besides one
telecom company deployment that will connect a town to a village (about 8
km long). We expect to use it for seismic monitoring purposes with DAS. As
far as we know they will use a standard method i.e. dig an 8 km long
trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct
besides the telecom one or to have it buried directly to the ground (out of
pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those
interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
----------------------
Distributed Acoustic Sensing - For more information on the Distribution
Acoustic Sensing Research Coordination Network, please go to:
https://www.iris.edu/hq/initiatives/das_rcn
Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe:
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Kasey Aderhold, Ph.D.
Project Associate | IRIS Instrumentation Services
202-407-7019 | kasey<at>iris.edu | (she/her)
Currently teleworking M-F, 10am-6pm ET
-
Dear All,
I would like to thank you for the detailed responses I got for my question.
We now have a clear view of how to approach the deployment and also on how
to choose the proper cable.
Since this discussion could be of some interest to other people I created a
summary with all the responses I received.
These can be found at this link:
https://docs.google.com/document/d/1mT6EkzBkWKAyaIGnCmn4JxI0xj9mjz6b_TSvBu-gcr8/edit?usp=sharing
I almost anonymized the answers, leaving only the first name and removing
family name and email. Hope this is ok
regards
Marco
Il giorno mer 4 mag 2022 alle ore 19:05 Kasey Aderhold (via IRIS) <
das-bounce<at>lists.ds.iris.edu> ha scritto:
Thank you, Marco, for starting off such a vigorous discussion. I've given
all timezones a fair shot at this and kept responses open, but I would like
to encourage folks to respond directly to one another now.
Given that this is a topic of interest, however, please get in touch with
me directly at kasey<at>iris.edu if you would like to be involved in a
discussion or panel on fiber emplacement techniques in the near future.
Cheers,
Kasey
On Tue, May 3, 2022 at 12:29 PM Marco Olivieri (via IRIS) <
das-bounce<at>lists.ds.iris.edu> wrote:
Dear All,
--
We have been offered to deploy our own fiber‐optic cable besides one
telecom company deployment that will connect a town to a village (about 8
km long). We expect to use it for seismic monitoring purposes with DAS. As
far as we know they will use a standard method i.e. dig an 8 km long
trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct
besides the telecom one or to have it buried directly to the ground (out of
pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those
interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
----------------------
Distributed Acoustic Sensing - For more information on the Distribution
Acoustic Sensing Research Coordination Network, please go to:
https://www.iris.edu/hq/initiatives/das_rcn
Topic home: http://ds.iris.edu/message-center/topic/das/ | Unsubscribe:
das-unsubscribe<at>lists.ds.iris.edu
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Kasey Aderhold, Ph.D.
Project Associate | IRIS Instrumentation Services
202-407-7019 | kasey<at>iris.edu | (she/her)
Currently teleworking M-F, 10am-6pm ET
----------------------
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Hi Marco
Would recommend the FOSA publications on this topic – they sweep up a LOT of what has been said.
https://www.fiberopticsensing.org/page/installation-considerations
There isn’t one for seismic purposes but the other land based ones will suffice (e.g. pipelines)
Other comments:
* If gel filled – loose tube and NOT dry powder filled
* Tight buffered will be excellent coupling but of course if over strained will have a higher risk of breakage
* Sensitivity wise an unarmoured cable in a conduit has similar sensitivity to an armoured direct burial cable – some slight deltas
Regards
Chris
Dr Chris Minto
Engineering Director
Mobile: +44 7500 782 508
Email: chris.minto<at>optasense.com<chris.minto<at>optasense.com>
From: das-bounce<at>lists.ds.iris.edu <das-bounce<at>lists.ds.iris.edu>
Sent: 03 May 2022 17:26
To: Distributed Acoustic Sensing <das<at>lists.ds.iris.edu>
Subject: [IRIS][das] Fiber‐Optic Cable deployment
Dear All,
We have been offered to deploy our own fiber‐optic cable besides one telecom company deployment that will connect a town to a village (about 8 km long). We expect to use it for seismic monitoring purposes with DAS. As far as we know they will use a standard method i.e. dig an 8 km long trench, bury a pvc duct and insert the fiber‐optic cable in it.
The question is: Would it be better to insert our cable in the pvc duct besides the telecom one or to have it buried directly to the ground (out of pipe)? Do you know any paper or technical report that discusses this task?
Please respond to me directly and I will compile responses for those interested.
Any hint would be appreciated.
Thanks
Marco Olivieri
Peter Hubbard
Jonathan Ajo-Franklin
Francisco López Torres
Daniel DANSKIN
FangDad Fabulous
NEAL E LORD
Scott W Tyler
Kurt Feigl
Douglas E Miller
Barry Freifeld
Philippe Jousset
kasey.aderhold@iris.edu
Chris Minto
