morgans report of 14/4 on website, page-72

Of course one or some unprofitable wells don't reduce the entire field to zero, just like one or more profitable wells don't automatically bring it above zero. A reserve figure of zero requires the average well to be unprofitable.

I'm not sure I agree with your assertion of MAD's profitability.

Yes, a company can still drill and pump oil even if it's unprofitable, and yes, that 'uses plenty of cash flow', and yes, that does sometimes happen for various reasons. You may be familiar with an example.