DUBAI (Reuters) - Investment in exploration and production will have to start increasing soon to help balance the global oil market, Schlumberger CEO Paal Kibsgaard told a conference in Dubai on Monday.

The medium- to long-term oil environment will remain subject to periods of volatility and the industry may see fewer and larger service operators in the future, the oilfield services company boss said.

(Reporting by Maha El Dahan and Hadeel al Sayegh; writing by Tom Arnold; editing by Jason Neely)