SPECIFICATION FOR ROTARY DRILL STEM ELEMENTS 11

Table 34 — Neck diameters and connections

Neck Diameter

Connection, Box x Pin

All dimensions are in millimeters

Box Connection, Near Bit Stabilizer

lower

121 NC38 3-1/2 REG 165 NC46 4-1/2 REG 171 NC50 4-1/2 REG 203 6-5/8 REG 203 6-5/8 REG 241 7-5/8 REG 241 7-5/8 REG 241 to 279

7-5/8 REG

279 8-5/8 REG

6-5/8 REG 7-5/8 REG 7-5/8 REG 7-5/8 REG 8-5/8 REG 8-5/8 REG

Inside Diameter

51 71 71 71 71 76 76 76 76

Blade Diameter 130 to 187 191 to 200 203 to 244 241 to 394 397 to 508 311 to 508 397 to 660 508 to 660 >660

12.6.3 Blade Dimensions

The blade diameter, length and number shall be as indicated in Table 35 (Table A.35).

Table 35 — Blade dimensions

All dimensions are in millimeters

Up-hole and downhole

a

blade taper angles Blade diameter +0/–0,8 Number of Blades, Integral Number of Blades, Welded Blade width (integral) ± 6 Blade width (welded) ± 6 Crown length min (see note)

130 to 187

3

191 to 244

3

30 ± 5 degrees integral 30-45 degrees welded 245 to 311 3 or 4

318 to 394

3 or 4

397 to 508 3 or 4

>508

4

3 3 3 3 3 3 51 64 76 89 102 102 38 51 51 64 76 76 305 406 457 457 508 508 NOTE The crown may be tapered at customer’s option to form a “watermelon geometry” as in Figure 15. The crown length includes the

length of this shallow taper

a The taper angle requirement applies only for the first 25 mm radially from the blade surface. If the blade height exceeds 25 mm, the taper angle for the remainder of the height may be up to 45 degrees at the manufacturer’s discretion. See Figure 14.

12.6.4 On gauge blade diameter

For a gauge stabilizer, the blade diameter shall be defined using a ring gauge of the same dimensions as the bit Not-Go gauge of Sub-clause 9.2.3.1 for the given nominal diameter. Other measuring methods may be used, with the ring gauge as arbiter in case of dispute.

The diametrical clearance to this gauge shall be 0 mm to 0,76 mm (0 in. to 0.03 in.) 12.6.5 Blade spiral

The spiral shall be as defined on the purchase order, and interpreted according to Table 36. Unless otherwise specified, the spiral shall be right-hand.

12 ADDENDUM 3 TO ANSI/API SPECIFICATION 7-1/ISO 10424-1

Table 36 — Blade spiral definitions

Spiral Description Straight blade Open spiral Full spiral Tight Spiral

Wrap Angle (see Figure 12)

Not applicable 180 – 220 degrees 300 – 350 degrees 500 – 600 degrees

12.7 Connections and bevel diameters

12.7.1 Size and type

The connections shall be as described in Table 34 (Table A.34). The bevel diameters for the upper connection of all stabilizers, and for the lower connection of string stabilizers shall be the same as those defined in Table 14 (Table A.14). The bevel diameter for the lower connection of near-bit stabilizers shall be as defined in Table 19 (Table A.19).

12.7.2 Gall Resistant Treatment for Threads and Sealing Shoulders

For standard steel stabilizers, a gall-resistant treatment of zinc or manganese phosphate shall be applied to the threads and sealing shoulders of both the upper and lower connections. Application of the treatment shall be after completion of all gauging. The treatment type shall be at the discretion of the manufacturer.

Key 1 2

Increased taper angle

Depth to start of increased taper angle

Figure 14 — Blade taper geometry

SPECIFICATION FOR ROTARY DRILL STEM ELEMENTS 13

Key 3 4

Crown length definition for watermelon geometry Typical crown taper of watermelon geometry

Figure 15 — Watermelon geometry

12.8 Customer information

12.8.1 Required information from customer a) Stabilizer type: String or near-bit b) Integral or welded c) Stabilizer (blade) diameter

d) Wrap: Tight Spiral, Full Spiral, Open Spiral or Straight e) Neck size and connections 12.8.2 Optional requirements

a) Connection Stress Relief features, per ISO 10424-2 (API Spec 7-2) b) Connection cold working

c) Connection surface treatment (optional for non-magnetic only) d) Non-magnetic e) Abrasion protection type f) Left hand spiral

g) Float valve recess on near-bit stabilizer

12.9 Marking

The following information shall be marked on a marking recess with steel stamps or milled lettering a minimum of 6 mm (0.25 in.) in height. This recess shall be located on the upper neck, as shown in Figure 1 within 100 mm (4 in.) of the stabilizer blades.

14 ADDENDUM 3 TO ANSI/API SPECIFICATION 7-1/ISO 10424-1

a) Manufacturer name or mark.

b) Blade diameter (add – “NM” for a non-magnetic stabilizer). c) ISO 10424-1 and/or API Spec 7-1. d) Upper Connection size and style. e) Internal diameter. f) Serial number.

g) Lower Connection size and style. Examples:

A 447,7 mm (17 5/8 in.) stabilizer, with 76 mm (3 in.) bore, manufactured by A B Company, shall be stamped: A B Co. (or mark) 447,7 (17 5/8) ISO 10424-1 and/or API Spec 7-1 6 5/8 REG 76 (3) Serial No. 6 5/8 REG A 209.5.mm (8 1/4 in.) Non-magnetic stabilizer, with 71,4 mm (2 13/16 in.) bore, manufactured by A B Company, shall be stamped:

A B Co. (or mark) 209,5 (8 1/4) NM ISO 10424-1 and /or API Spec 7-1 NC50 71,4 (2 13/16) Serial No. NC50