Exhibit 21
Significant Subsidiaries
Listed below are the significant first tier subsidiaries of the Registrant, along with the total number of active
subsidiaries directly or indirectly owned by each as of December 31, 2010. Certain second and third tier subsidiaries,
though included in the numbers, are also shown by name. Ownership is 100% unless otherwise indicated. The business
activities of the subsidiaries have been keyed as follows: (a) Oilfield Services, (b) WesternGeco, (c) General/Multiple
Segments.
U.S.
Non-U.S.
Schlumberger B.V., Netherlands (c)
6(a)
79(a)
1
22(b)
2
12(c)
Schlumberger Canada Limited, Ontario (c)
Schlumberger SA, France (c)
Services Petroliers Schlumberger, France (a)
Schlumberger Norge AS (c)
Schlumberger Holdings Corporation, Delaware (c)
Schlumberger Technology Corporation, Texas (c)
Smith International Inc (c)
Schlumberger UK Limited
Schlumberger Plc, UK (c)
Schlumberger Oilfield UK Plc, UK (a)
WesternGeco Limited, UK(b)
Schlumberger Antilles N.V., Curaçao (a)
2(a)
Schlumberger Oilfield Holdings Limited, BVI (c)
1(a)
136(a)
3
28(b)
4
Schlumberger Holdings Limited, BVI (a)
11(c)
5
Dowell Schlumberger Corporation, BVI (a)
Schlumberger Middle East S.A., Panama (a)
Schlumberger Offshore Services Limited, BVI (a)
Schlumberger Overseas, S.A., Panama (a)
Schlumberger Seaco, Inc., Panama (a)
Schlumberger Surenco, S.A., Panama (a)
WesternGeco Seismic Holdings Limited, BVI (b)
Schlumberger Technology Corporation, Texas (c)
11(a)
6
1(b)
2(b)
4(c)
WesternGeco L.L.C., Delaware (b)
1 Includes eight majority-owned subsidiaries and two 50%-owned subsidiary.
2 Includes one majority-owned subsidiary and one 50%-owned subsidiary.
3 Includes three majority-owned subsidiaries and two 50%-owned subsidiaries.
4 Includes one majority-owned subsidiaries.
5 Includes one majority-owned subsidiary.
6 Includes one majority-owned subsidiary and one 50%-owned subsidiary
