ISO 10427-1 pdf download – Petroleum and natural gas industries —Equipment for well cementing – Part 1: Casing bow-spring centralizers

ISO 10427-1 pdf download – Petroleum and natural gas industries —Equipment for well cementing – Part 1: Casing bow-spring centralizers.
NOTE Restoring torce values can vary based on installaton methods.
3.6
rigid centralizer
c.ntratzer manufactured with bows that do not flex
3.7
running force
maxanum farce requ Wed to move a centralizer through a specified weilbor. diameter
NOTE Running-force values can vary depending on the Wistalalion methods.
3.8
standoff
smallest distance between the outside diameter of the cassig and the wethore
3.9
standoff ratio
ratio of standoff to annular clearanci
NOTE It Is expressed as a percentage.
3.10
starting torc.
maumtsn force required to Inserts centralizer into a specified wellbore diameter
NOTE Starting-forc, values can vy depending on the irwtaletion methods,
3.11
stop collar
device attached to lie casing to prevent movement of a casing centralizer
NOTE A alOp collar cen be either en Independent piec. of equipment or integral with the oentralzer.
4 Requirements
4.1 FunctIons of a centralIzer
The purpose of a casrig centralizer is to facilitate running casing to the desired depth and to assist In centring the casing in the welibore. On. of the main objectives of o.ntralizrng a casing string is to facilitate a good cementing. thereby isolaling fluids from different zones A bow-spring centralizer can be constructed In various weys, using vanous types, shapes and quantities of bow spring.
4.2 Starting force
The maiumian starting force shall be less than the weight of 12,19 m (40 ft) of casing of medlum linear mass as defined in Table 1 The maximum starling force shal be determined for a centralizer In new, fully assembled condition,
4.3 Restoring forCe
The minimial, restoring force or a 67% standoff ratio shall not be less than the values shown rn Tablet. See k2 for the derivation of the requirements.
6.1.5 With the centralizer resting on the edge of the outer pipe，apply a load to the inner pipe to pull thecentralizer into the outer pipe.
6.1.6Take readings of force used, from the time the load is first applied until the centralizer is completely insidethe outer pipe.Report the maximum force as the starting force after compensation as in 6.1.1.
6.2Running-force test
6.2.1 The running force represents the maximum force required to slide the inner pipe inside the outer pipe oncethe force reading has become steady (after compensating for the weight of the inner pipe and attachments).
6.2.2 The result of this test is not required to conform to a maximum value. However, the test shall be performedand the results recorded.
6.2.3 The running-force test may be performed with the starting-force test, or carried out separately.
6.2.4 Take readings of force used from the time the centralizer is inside the outer pipe until the inner pipe iscompletely in place.Report the maximum force as the running force after compensation as in 6.1.1.
7Procedure for restoring-force test
7.Perform the test with the inner pipe and the outer pipe within 5° of horizontal, see Figure 2.7.2Prior to collecting the force data for the test, flex all bow springs 12 times.
7.3 Apply an external force to the outer pipe so that it will be transferred to the inner pipe vertically through thepoint of contact of the centralizer with the outer pipe, see Figure 2.
7.4Apply load and record load-deflection readings at a minimum of 1,6 mm (‘1，g in) increments until three times(±5 %) the minimum restoring force has been obtained, see Table 1.The travel distance to obtain 67 % standoffshall be determined for each test position.
7.5Repeat the process，testing the centralizer until each spring and each set of springs has been fested inpositions 1 and 2 as shown in Figure 3.