Exhibit 12.1

SCHLUMBERGER LIMITED AND SUBSIDIARIES

Computation of Ratios of Earnings to Fixed Charges

($ millions)

	Six Months Ended June 30, 2013			Year Ended December 31,
				2012			2011			2010			2009			2008
Earnings
Income from Continuing Operations before taxes	$	4,291		$	6,959		$	6,018		$	4,898		$	3,934		$	6,718
Add / (Deduct):
Fixed charges		348			674			580			424			425			472
Amortization of capitalized interest		2			2			2			2			1			1
Distributions from equity investments		24			81			26			80			106			58
Capitalized interest		—			—			—			(6	)		(28	)		(31	)
Equity Income		(50	)		(142	)		(90	)		(165	)		(209	)		(293	)
Total earnings	$	4,615		$	7,574		$	6,536		$	5,233		$	4,229		$	6,925
Fixed charges
Interest Expense (net of capitalized interest)	$	197		$	340		$	298		$	207		$	221		$	247
Add:
Capitalized interest		—			—			—			6			28			31
Interest component of rental expense (*)		151			334			282			211			176			194
Total fixed charges	$	348		$	674		$	580		$	424		$	425		$	472
Ratio of earnings to fixed charges		13.2			11.2			11.3			12.3			10.0			14.7

(*) 17.6% of operating lease rental expense.