Well Integrity Technical Section

Good day Dear Well Integrity Engineers and Experts. 

I would like to share my observations and synchronize with you my understanding (i.e. test if it is true) about patches and its applicability in different scenarios. 

New water injector well started exhibiting a TxA communication signs after 6 months operations. We have logged and installed a straddle tubing patch to stop TxA communication. The leak point in tubing was at 9100 ft MD (tubing connection) and leak rate was ~20 psi/hr. The patch design was MTM and lasted only 3 months. The surface WH injection pressure was high (3000 psi) during normal operations. The log was run and confirmed leak point at the same position again. Tubing was retrieved along with patch and inspected/tested at workshop. During the inspections it was not observed a significant corrosion across patch, but pressure tests failed. 

What is your experience with MTM straddle patches in such well conditions ? 

Thanks,

Tural 

Turai,

My observation has been similar to yours.

My ratio has been ~40% success rate
tested in the yard : OK
Installed : OK,
Pressure tested : OK

After the drillers and workover engineers are gone, then leaks begins....
usually 6 months to 2 year.

The only variable unaccounted for is the actual integrity of the tubular we are trying to patch.
As an example, on one well in the middle east, we ran a MFCT (multi finger caliper tool), MFL and even USIT on the casing.
There was some indentations, but the data looked good, we were almost at the decision point to run the MtM straddle.

Then for giggles, we ran a camera, and low and behold, we had a DP groove in the casing, <1mm deep, for almost 150m straight down the casing from the leak point and in a perfect spiral no less....
Had we set the 10 m patch as planned, it would have failed.....

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Basker Murugappan
Principal Production Technologist
Villalbilla, Spain
+34 644485970

Three basic rules:
1) Change is inevitable.
2) Everybody resists change.
3) You cant stop change
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The key to a successful patch starts with fully understanding the issue, well conditions and the full extent of the casing damage. I did a Distinguished Lecture tour in 2017-2018 "Wellbore Integrity Restoration: New life for old wells" where the process was walked through on how to identify the issue, quantify it and ultimately repair it. Link to the webinar Wellbore Integrity Restoration: New Life for Old Wells – SPE Energy Stream There are many different types of casing patches. The 2 primary types I deal with are expandable liners made from high ductility tubulars with elastomer sealing elements bonded to the outside that are compressed between the tubing or casing and the expanded liner and a corrugated tube that is wrapped with fiberglass and flexible epoxy that is re-formed downhole and pressed up against the ID of the tubular. The epoxy helps to seal between the patch and tubing and in small holes will press into the hole to aid sealing. This type of patch has been successful for over 60 years. It is critical to cover the full extent of the damage and properly prepare the inside of the tubing/casing to accept the patch and allow it to seal regardless of the type of patch you are installing. This is particularly true in the case of external corrosion which can be more difficult to detect. Regarding to MTM patches inside of un-machined ID of tubing/casing is going to be less forgiving than something with an elastomer or other high flexible element. There are some "patches" on the market that have a MTM seal with an elastomer back-up

Very good presentation @Greg Galloway, and great source of info (as usual, examples are eloquent). Thanks for sharing!

(side note to @Greg Hickey: this illustrates the power of a strong SPE library of events)

There seems to have been a few evolutions in the technology since you recorded this... I have not heard much on the geophone array tech, but there have been strong developments with Distributed FO Sensing (DFOS) SL or capillary, or advanced acoustics (and signal processing). Perhaps this explains why we haven't heard much about the geophone array tech? (however, feel free to share more info on companies which could still offer this)

On the resins, I will add that I've never used them either but remember from my sand control time (for pack consolidation) that resins very often were tricky to use from an HSE standpoint... a bit like toluene/xylene solvents we used back in the day. Efficient but highly problematic. Perhaps that would also explain the low adoption (that and the critical influence of temperature on polymerisation).

I'm curious re: some of the novel solutions like Biosqueeze... haven't used them either but they may be an interesting niche application (@Hayden Binde).

Finally I'll highlight the criticality (as you rightfully pointed out) of dimensional data for accurate determination of internal & external pressure rating of OCTG... a while back we worked with C-Fer in Canada on modelling a "reasonable" collapse rating of casing based on actual WT and ovality (internal yield is much less of an issue)... without this, determination would be a wild / blind guess at best (@Gang Tao I haven't given up on this ;).

For really demanding applications, fingerprinting the OCTG and then time-lapse of their dimensional data will probably become critical... along those line, Vallourec has been working on a robot to acquire accurate dimensional data for every joint, so assurance can be provided from the start (@Binh Nguyen) then logs would allow to check dimensional data over time so that expected mechanical performance can be assured.

Rgds.

@Pierre-edouard Vincent, thanks for looping us in!

BioSqueeze can be an effective solution for tubing/patch leaks (case study here), but it is critical there is adequate cement behind the leak for the technology to be successful (sounds like there wasn't the case in this application). Happy to discuss the technology/application with you, @Tural Yusubov, or anyone else interested in learning more.

Best,

Hayden Binde | Marketing & Sales Support Manager

406.202.3443 | hbinde@biosqueeze.com
130 N. Main Street | Butte, MT 59701

BioSqueeze.com 

Distributed fiber optic sensing with WL, SL or Cap Tune intervention would go a long way towards improved understandiig with location and other aspects of casing issues. Geophones acoustics is not a very practical solution given as advanced in fiber optic sensing in the last decade. 

We have experience in patch repair monitoring using fiber optics to assess the efficacy of repairs over time lapse spans of a year or more.  Spatial resiluton of 20 cm and strain detection down to less than 1 micro strain unit at 20cm resolution makes for a reliable diagnostic method that can be used in an engineered designed MIT test.  

These types of projects are done and reported in spe libraries.