Schlumberger Ltd. SLB 1.32 % said Tuesday that it will cut its workforce by an unspecific amount as the oil-field service giant pares its activity in 2016. Schlumberger said in a regulatory filing that it will “streamline its support structure.” The company didn’t provide further detail on the cuts. Schlumberger said it will book a $350 million pretax restructuring charge in the fourth quarter related to the layoffs. Schlumberger has been hurt by low commodity prices, which have pressured pricing and demand for its services from oil producers. The company, seen as a bellwether for the energy industry, in April announced it would cut 11,000 workers , bringing its layoffs to 20,000 employees.