While natural gas companies like ConocoPhillips and Chesapeake Energy Corporation are making big bets on wells that are supposed to extract energy from shale formations, the New York Times reported that an investigation of e-mails and documents shows industry insiders have doubts as to whether the companies will be able to deliver on their promises to investors.

In the e-mails, energy executive, industry lawyers, state geologists and market skepticism question whether natural gas companies are exaggerating how productive their wells will be, the Times reported.

The Times said it researched well data and found that many of them are surrounded by less-productive zones that cost more to drill and operate than the resulting gas is worth. The newspaper said its investigation found that in many of the wells, the amount of gas produced is falling faster than the companies had expected.

None of the e-mails explicitly accuse any companies of breaking the law, the Times said.

ConocoPhillips declined to comment. Chesapeake could not be reached for comment.

(Reporting by Helen Chernikoff; Editing by Leslie Adler)

The New York Times Conocophillips