ANSI API RP 10D-2:2004 (2020) pdf download.Recommended Practice for Centralizer Placement and Stop-collar Testing.
This part of ISO 10427 provides calculations for determining centralizer spacing, based on centralizer performance and desired standoff, in deviated and dogleg holes in wells for the petroleum and natural gas industries. It also provides a procedure for testing stop collars and reporting test results.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 11960, Petroleum and natural gas industries — Steel pipes for use as casing or tubing for wells
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1
annular clearance for perfectly centred casing
wellbore diameter minus casing outside diameter divided by two
3.2
centralizer permanent set
change in centralizer bow height after repeated flexing
NOTE A bow-spring centralizer is considered to have reached permanent set after being flexed 12 times.
3.3
flexed
condition of a bow-spring when a force three times the specified minimum restoring force (± 5 %) has been applied to it
[ISO 10427-1:2001, 3.1]
NOTE Specified minimum restoring force values are found in Table 1 of ISO 10427-1:2001.
3.4
holding device
device employed to fix the stop coflar or centralizer to the casing
EXAMPLE Set screws, nails, mechanical dogs and epoxy resins.
[ISO 10427-1:2001, 3.2]
3.5
holding force
maximum force required to initiate slippage of a stop collar on the casing
[ISO 10427-1:2001, 3.3]
3.6
hole size
diameter of the wellbore
[ISO 10427-1:2001]
3.7
limit clamp
equivalent term for a stop collar
3.8
restoring force
force exerted by a centralizer against the casing to keep it away from the wellbore wall
NOTE Restoring-force values can vary based on the installation methods.
[ISO 10427-1:2001, 3.5]
3.9
rigid centralizer
centralizer manufactured with bows, blades or bars that do not flex
NOTE Adapted from ISO 10427-1:2001, 3.6.
3.10
running force
maximum force required to move a centralizer through a specified wellbore diameter
NOTE Running-force values can vary based on the installation methods.
[ISO 10427-1:2001]
3.11
sag point
point where the casing deflection is at a maximum
NOTE Casing that is supported at two points will tend to sag between the support points, this sag is called the casing sag or casing deflection.
3.12
slippage force range
range of forces required to continue to move a stop collar after the holding force has been overcome
3.13
solid centralizer
centralizer manufactured in such a manner as to be a solid device with nonflexible fins or bands
NOTE These centralizers have solid bodies and solid blades.
3.14
standoff
smallest distance between the outside diameter of the casing and the welbore
[ISO 10427-1:2001, 3.8].ANSI API RP 10D-2 pdf download.