Well Integrity Technical Section

Dear SPE Colleagues,

We are developing an ultra-sound based calliper tool that can address existing limitations by multi-finger calliper (MFC) tool, such as in geothermal wells when measurement of pipe radii change can vary from 7" liner to 9-5/8" till surface e.g. 15" in one run. 

I read from various MFC product brochures that the tool's radial accuracy can be up to 0.03" (0.76mm) and radial resolution 0.003" (0.076mm). A tool manufacturer confirmed that if calibrated correctly, such kind of accuracy can be realised. Meanwhile, there are electro-magnetic tools that claim to have 100% all-around defect sensing whilst MFC can only sense 10-30% internal defect. 

Now from a user's perspective, what would be the ideal delivered measurement results, with single or combined tooling? What level of accuracy / resolution is absolutely necessary, either set by the operator or regulator?  I recall an operator use, e.g. a rule of thumb to determine when a work-over is obligatory:  maximum acceptable level being 50% metal loss, averaged to 30cm or so of tubing length interval, which seems to be very lenient with regard to tool's technical capabilities.  Are there any specific regulation, and whether operators self-apply well integrity rules or criteria in terms of metal loss / defect? Any public doc that I can refer to?

Any comments on how I should reconcile the very high resolution/accuracy level that the MFC can achieve, with the actual application requirement (if lower)? 

I acknowledge that several questions are jumbled together but appreciate any help to clarify and educate.

Also quote one user's justification of using ultra-sound based measurement tool below:

"We typically run multifinger callipers in gas storage facilities onshore to verify the well integrity. This is a (yearly?) requirement. Similar requirements will be in place for future CCS wells (CO2 storage) or maybe later H2 storage sites. Typically these multifinger calipers will inspect tubing on deformation. In our current abandonments we run sometimes multifinger calipers when we expect issues (damage or deformation) on liners before we go in with the ultra-sonic cement bond logging tools or other (expensive) tools that might get stuck. Having said that the multifinger calipers are not that inexpensive to run especially if you want to have a large number of caliper fingers (64 or more). Possibly the ultra-sonic caliper can also tell us more on scaling, position and status of nipples and safety valves, liner hanger. Measuring in one run all the different casing size that would be a real advantage."

Best regards,
Junying Chang

Hello Junying

Casing integrity along the well life cycle is key to meet safe well construction, then exploitation and ROE.

I suggest here a few SPE papers to fully appreciate how central are MFCL tools resolution/accuracy and logs interpretation for high spec wells such as HPHT and High Energy Geothermal wells.
Casing wear assessment and mitigation are essential to sound casing design and well life cycle for such wells (deep wells, in hard rock, with potential low ROP and high RPM generating significant casing wear). One must be aware of it and assess and manage it during well engineering casing design and well construction). 

SPE-183386-MS - Systematic Field Validation of New Casing Wear Quantification Process (F. Aichinger, N. Dao, L. Brillaud, B. Nobbs, Drillscan; A. Delapierre, C. Pinault, X. Rossi, Total E&P)

SPE/IADC-183388-MS - Casing Wear and Stiff String Modelling Sensitivity Analysis - The Contribution of Drill Pipe Pipe-Body and Tool-Joint on Casing Contact (D. Vavasseur, N. Mackenzie, Mærsk Oil North Sea UK Ltd; B. Nobbs, L. Brillaud, F. Aichinger, N. Dao, Drillscan)
SPE-202828 - Casing Wear Modelling: A comparison between MFCL and 3D Stiff String Model
SPE-173143 - Assessing Casing Wear in the absence of a baseline calliper Log (S.J.Sawaryn BP - P.D. Patilllo, CGS, ...)

Regards
Régis

Few comments I would like to share, 
1. MFC is the simplest tool involving physical measurement of inside dia by use of arms/ fingers  for well integrity diagnostic work for inside tubing or casing. 

2. it is great tool and could answers all
inside well problems if run properly I mean tool calibration, running speed etc acquiring repeat pass in area of interest. 

3. For running in variable pipe size, you can run with extended fingers tool and get the job objectives meet. 

4. making ultra sound based tool will
make a simple caliper tool more complex and would add a degree of error. Use of USIT log is great but still add complex processing. 

5. EM tools are great to address severe issues for overall pipe evaluation I mean both inside I and outside of pipe. However it has limitations too. The estimation of wall loss through em log comes with certain percent of accuracy. It is good tool for qualitative analysis but I can say average for quantitative analysis for wall loss. 

In general, I think it is better to improve tool limitations by improving existing technology but not by modifying tool physics. 

this is just my personal opinion. 

Kishore Maheshwari 

Original Message:
Sent: 04-16-2023 03:09 PM
From: Regis Studer
Subject: Measurement of tubing / casing integrity and MFC

Hello Junying

Casing integrity along the well life cycle is key to meet safe well construction, then exploitation and ROE.

I suggest here a few SPE papers to fully appreciate how central are MFCL tools resolution/accuracy and logs interpretation for high spec wells such as HPHT and High Energy Geothermal wells.
Casing wear assessment and mitigation are essential to sound casing design and well life cycle for such wells (deep wells, in hard rock, with potential low ROP and high RPM generating significant casing wear). One must be aware of it and assess and manage it during well engineering casing design and well construction). 

SPE-183386-MS - Systematic Field Validation of New Casing Wear Quantification Process (F. Aichinger, N. Dao, L. Brillaud, B. Nobbs, Drillscan; A. Delapierre, C. Pinault, X. Rossi, Total E&P)

SPE/IADC-183388-MS - Casing Wear and Stiff String Modelling Sensitivity Analysis - The Contribution of Drill Pipe Pipe-Body and Tool-Joint on Casing Contact (D. Vavasseur, N. Mackenzie, Mærsk Oil North Sea UK Ltd; B. Nobbs, L. Brillaud, F. Aichinger, N. Dao, Drillscan)
SPE-202828 - Casing Wear Modelling: A comparison between MFCL and 3D Stiff String Model
SPE-173143 - Assessing Casing Wear in the absence of a baseline calliper Log (S.J.Sawaryn BP - P.D. Patilllo, CGS, ...)

Regards
Régis

Hi Junying

The concept of an ultrasonic tool for geothermal applications as a substitute or complement to multi-finger caliper is certainly interesting. I would say that accuracy for a multi-finger caliper in geothermal is largely dependent on the objective. If there is severe deformation, then the necessity for high accuracy diminishes. However, accuracy does matter if the objective is the monitoring of wall thinning, for example. With such an application, the absolute measurement is critical to enable dependable time-lapse comparisons, and a technology that can make a perfect measurement would be beneficial. I don't know whether that is feasible for an ultrasonic tool. There are now several ultrasonic tools on the market for assessing the condition of tubulars but there is, perhaps, only one that is capable of operating above 175degC or so, which is easily achievable for a couple of existing caliper technologies.

Regards

Reza Khastoo
Product Line Manager, Cased Hole Services

Scientific Drilling International
Mob: +31 (0) 625512324
SDI Cased Hole Services<https: www.linkedin.com/showcase/sdi-chs/="">


Original Message:
Sent: 4/17/2023 2:27:00 AM
From: Kishore Maheshwari
Subject: RE: Measurement of tubing / casing integrity and MFC

Few comments I would like to share, 
1. MFC is the simplest tool involving physical measurement of inside dia by use of arms/ fingers  for well integrity diagnostic work for inside tubing or casing. 

2. it is great tool and could answers all
inside well problems if run properly I mean tool calibration, running speed etc acquiring repeat pass in area of interest. 

3. For running in variable pipe size, you can run with extended fingers tool and get the job objectives meet. 

4. making ultra sound based tool will
make a simple caliper tool more complex and would add a degree of error. Use of USIT log is great but still add complex processing. 

5. EM tools are great to address severe issues for overall pipe evaluation I mean both inside I and outside of pipe. However it has limitations too. The estimation of wall loss through em log comes with certain percent of accuracy. It is good tool for qualitative analysis but I can say average for quantitative analysis for wall loss. 

In general, I think it is better to improve tool limitations by improving existing technology but not by modifying tool physics. 

this is just my personal opinion. 

Kishore Maheshwari