Actually, njg, the exact opposite is what Enron did. They not only increased, rather than decreased, the value of their assets through creative accounting, they actually built fictitious assets on their books, all to inflate the estimated value of the company's physical assets.
Although it makes for good fodder on Bloomberg and other media outlets, Chesapeake actually followed the intent of modern accounting laws quite well, with good transparency. As djl pointed out, the oil is still in the ground, but unprofitable to recover at current commodity prices. When those prices rise again in the future, which could be quite some time, Chesapeake will simply add those back into their recoverable reserves. The operative word there is "recoverable". This is a moving target, primarily affected by two things: commodity prices and advances in technology.