$斯伦贝谢(SLB)$ Schlumberger (NYSE:SLB) says Executive VP and CFO Simon Ayat will step down from the position effective Jan. 22, to be succeeded by current VP of finance Stephane Biguet.Ayat's career with SLB began in 1982 and spanned a variety of management positions from Paris, Houston and Dallas to the Middle East and Far East; he will stay on as Senior Strategic Advisor for two years.Biguet has spent 24 years at SLB, holding senior positions in finance and operations at the field and headquarters levels.