downhole casing inspection using mfc and odt - bzivanov-ddyson

7/24/2019 Downhole Casing Inspection Using MFC and ODT - BZivanov-DDyson

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Downhole casing inspection using Multi

finger caliper (MFC) and Omni directionaltool (ODT)

Borislav Zivanov, Hotwell AustriaDerek Dyson, HotwellUS

Hotwell Handelsges.m.b.H

Oedenburger Strasse 6

7013 Klingenbach, AUSTRIA

Tel.: +43 (0) 2687 – 48058

Fax: +43 (0) 2687 – 48059

[email protected]

www.hotwell.at

best components | simple design | rigorous testing | no sacrifice to performance

1Title of the Presntation / Author



Abstract

2 Title of the Presentation / Author

• In last year MFC and ODT has been widely used

worldwide and many open question about well

conditions were successfully answered such as

corrosion, leaks, pits, mechanical damages,

position and defect of downhole equipment, etc.• This article is overview of testing, field examples

and basic theory about combination between multi

finger caliper and omni directional tool. Several

examples from test and commercial wells will be

present in text.



Introduction

• Casing inspection measurements are used toexamine the casing or tubing in a well.

• The applications of these include the location of pits,

leaks, and holes in the casing. With MFC and ODT, a

pit on the outside can be discriminated from one theinside wall of the pipe.

• Corrosion management is an important application.

Certain surveys are necessary for proper cathodicprotection planning. Often surveys are run on a time

lapse basis to monitor the progress of corrosion with

time.




Introduction

•Casing and tubing placed in well bores may suffer from

damage due to corrosion or mechanical distress. Corrosion is

caused by natural electrical currents that flow in the earth,

and from man-made currents from power lines and surface

equipment.

• Holes in tubing or casing caused by corrosion can seriously

affect production rates and fluid composition, resulting in

economic loss.




Omni directional survey


Hotwell magnetic thickness survey determine metal loss

from pipe both from inner and outside in downhole

environment. There are several reasons for metal losscorrosion, mechanical damage, electromechanical

process and etc. Corrosion often results from one or

more of a family of electrochemical process. When ODT

survey is run in conjunction with MFC (Multi finger caliper)survey to evaluate casing loss, the surveys provide

information which indicates whether the corrosion

is internal or external.






Omni directional survey• Determines casing joints of different weight.

• Locates evidence of casing defects and mechanical wear in

casing.

• Monitors progress of corrosion or mechanical wear throughperiodical survey.

• Locates severe pits or holes in casing.

• Locates casing collars or other casing string hardware

(centralizers, scratchers, baskets, packers, etc.)

• Locates the bottom of outside casing strings.• Locates the bottom of outside casing strings pipes.

• Confirms locations of perforations.

• Determines economic value of casing when considering

well abandonment.



Omni direction tool

OMNI DIRECTIONAL THICKNESS TOOLSPECIFICATIONS

2 7/8” 3 5/8”• Tool Length: 0,85m (33,5”) 0,85m (33,5”)

• Diameter: 73 mm 89 mm

• Weight: 15kg (33lbs) 17.5kg (39lbs)

• Pressure Rating: 15000 PSI 15000 PSI

• Temperature Rating: 175°C (350°F) 175°C (350°F)




Multi finger caliper tool

Multi-finger casing caliper logs are mechanical

casing inspection devices. Using from 24 to 56

fingers, depending on the diameter to bemeasured. The tool gives very high resolution,

radially and vertically, to identify casing corrosion

ranging from small pits and scale to axial splits.

The tool can be opened and closed downhole.

All raw data and computations are available at

the well site.








Cover

(A)

Roller

centralizers (B)

Cable head sub

(C)

Feeler finger

(D)



Multi finger caliper


As caliper moves over casing, the feeler arms follow the contour of the

casing’s inside wall. When feeler fingers are opened or closed, themechanical actuating mechanism of the tool convert the radial

movement of the measuring finger to axial displacement of the iron core

of placement transducer. Displacement of inner core is converted to

output electrical signal as a result of the axial iron core displacement of

displacement transducer. Signal is subsequently enter A/D converter and as telemetry signal sent to surface logging equipment.



Multi finger caliper




MFC and ODT


MFC and ODT

ODT vs MTT: The initial reasoning for the design of the ODT

was to replace the older style Computalog MTT tool. The tool

was being run by customers who wanted a new and improved

version that could be run digital through the caliper tool.

Below is an example showing the results when logged on the

same well.



Case Studies




MFC and ODT


MFC and ODT

Casing Wear: The following casing was logged in West

Texas. The presence of CO2 and H2S, as well as the age of

the wells, requires the constant maintenance and check of

pipe integrity. The following are screen shots of the bottom of

the casing. It is easily noticed from the caliper that the ID of

the casing is now larger than nominal pipe od. This is also

confirmed through the ODT, where the thickness clearly

mirrors the caliper results. After the completion of logging, thewell was pressure tested, in which case the pipe burst,

verifying the caliper and odt results.



Case Studies




Case Studies

• Perforations - New: The following examplewas logged following perforating. It is easily

noticed from the caliper that the perforation

holes are clean. The odt shows noticeable

decrease in thickness across this zone as well.

• This example also displays the repeatability of

the ODT tool. Notice the odt through the

collars and through the perforated zone. This

confirms the metal loss noticed around 2764

feet.17 Title of the Presentation / Author



Case studies




Title of the Slide

• Perforations - Squeezed: The perforations inthe following example are known to have

been squeezed. Notice the smaller projections

of the caliper as well as the odt through this

zone. In some cases, the caliper will not read

any perforations and the results will need to

be drawn solely from the odt readings.




Case studies




Case studies

• Perforations - Wear: The following example was logged through

an older well with a perforated zone. The caliper and odt

showed massive wall loss through this zone.




Case studies

• Well Completion Fixtures: The following showsan example of a gas lift. While logging the

well, the caliper showed a large diameter

which raised concern with the engineer. It was

then noticed from the odt that the wall

showed to be thicker, confirming that the

casing was not parted or damaged internally.

After discussing with the company man, it wasdiscovered that there is a gas lift installed

here, confirming our results.




Case studies




Conclusion

The results from the field so far have been very

positive and have proven to be a successfulmethod in monitoring and evaluating well

conditions. Each tool plays a critical role in

casing inspection analysis.


downhole casing inspection using mfc and odt - bzivanov-ddyson

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