Semi Rigid DB & SB Centralizer

Semi Rigid - DB
Asta Semi Rigid Centralizer – Double Bows features uniquely profiled bows that simultaneously provide the operator with those features found desirable in both spring bow and rigid centralizers. The design of the semi positive or semi rigid centralizer allows complete centering in under and slightly over gauge holes while providing the same centering force that can be produced with positive or rigid centralizer. The double bows (tandem) profile of the semi-positive or semi-rigid bow provides restoring forces that far exceed those standards set forth in API Specification 10D which normally associated with rigid centralizers. Available in Slip On and Latch On Type, and available in all sizes ranging from 4 1/2” to 13 3/8” for any hole combination.

Semi Rigid - SB
Asta Semi Rigid (single bow) is almost similar with Semi Rigid (double bow), designed for well where differential sticking may occur and low starting & running force are desirable to achieve easy running of casing without losing the high centering force required for proper casing stand-off. This centralizer is designed for small-clearance casing-to-hole size applications. The centralizer will perform as a standard bow centralizer in holes up to 1/2” smaller than the centralizer’s nominal OD. When run in holes less than 1/2” smaller than the OD, the center of the centralizer contacts the casing OD, performing as a rigid centralizer. With high restoring force on less spring deflection, this centralizer is excellent for deviated and horizontal wellbores. Available in Slip On and Latch On Type , and available in all sizes ranging from 3 1/2” to 13 3/8” for any hole combination.

Table 1: Centralizer Product Specification
Casing Size (in) Hole Size (in) Number of Bow Band ID (in) Average Bow OD (in) Max. Starting / Running Force (lbf) Min. Restoring Force at 67% stand off (lbf)
API Asta API Asta
3-1/2 6 4 3.700 6.000 396 <150 396 3100
4 6 4 4.200 6.000 454 <150 454 3200
4-1/2 6 4 4.700 6.000 464 <150 464 3100
4-1/2 8-1/2 4 4.700 8.500 464 <150 464 2800
7 8-1/2 6 7.200 8.500 1040 <150 1040 3000
7 9-1/2 6 7.200 9.500 1040 <150 1040 2800
9-5/8 12-1/4 6 9.840 12.250 1600 <150 1600 3300
13-3/8 17-1/2 8 13.600 17.500 2440 <150 1220 3300
Notes: Other size & requirement are available based on request.

Ordering Suggestions
To assure the correct size and type of equipment is obtained, please specify:
1. Casing O.D on which the equipment will be used.
2. Hole size or casing I.D in which the equipment will be placed.
3. Any restriction through which the equipment will be run.

Product Picture

Semi Rigid Double Bow Centralizer Semi Rigid Single Bow Centralizer