WASHINGTON (AP) -- BP took measures to cut costs in the weeks before the catastrophic blowout in the Gulf of Mexico as it dealt with one problem after another, prompting a BP engineer to describe the doomed rig as a "nightmare well," according to internal documents released Monday.

The comment by BP engineer Brian Morel came in an e-mail April 14, six days before the Deepwater Horizon rig explosion that killed 11 people and has sent tens of millions of gallons of oil into the Gulf in the nation's worst environmental disaster.

The e-mail was among dozens of internal documents released by the House Energy and Commerce Committee, which is investigating the explosion and its aftermath.

In a letter to BP CEO Tony Hayward, Reps. Henry Waxman, D-Calif., and Bart Stupak, D-Mich., noted at least five questionable decisions BP made in the days leading up to the explosion.

"The common feature of these five decisions is that they posed a trade-off between cost and well safety," said Waxman and Stupak. Waxman chairs the energy panel while Stupak heads a subcommittee on oversight and investigations.

"Time after time, it appears that BP made decisions that increased the risk of a blowout to save the company time or expense," the lawmakers wrote in the 14-page letter to Hayward. "If this is what happened, BP's carelessness and complacency have inflicted a heavy toll on the Gulf, its inhabitants, and the workers on the rig."

The letter, supplemented by 61 footnotes and dozens of documents, outlines a series of questions Hayward can expect when he comes before Stupak's subcommittee on Thursday.

The hearing will be Hayward's first appearance before a congressional committee since the explosion and sinking of the BP-operated Deepwater Horizon rig. BP America President Lamar McKay and other officials represented the company at earlier hearings.

The letter by Waxman and Stupak focuses on details such as the design of the well, saying that the company apparently chose a riskier option among two possibilities to provide a barrier to the flow of gas in space surrounding steel tubes in the well.

Despite warnings from its own engineers, "BP chose the more risky casing option, apparently because the liner option would have cost $7 to $10 million more and taken longer," Waxman and Stupak said.

In the brief e-mail, Morel said the company is likely to make last-minute changes in the well.

"We could be running it in 2-3 days, so need a relative quick response. Sorry for the late notice, this has been nightmare well which has everyone all over the place," Morel wrote.

BP apparently rejected advice of a subcontractor, Halliburton Inc., in preparing for a cementing job to close up the well. BP rejected Halliburton's recommendation to use 21 "centralizers" to make sure the casing ran down the center of the well bore. Instead, BP used six centralizers.

In an e-mail on April 16, a BP official involved in the decision explained: "It will take 10 hours to install them. I do not like this." Later that day, another official recognized the risks of proceeding with insufficient centralizers but commented: "who cares, it's done, end of story, will probably be fine."

Confidential Email Transcript:
From: Hafle, Mark E Sent: Wed Apr 14 23:09:46 2010
To: Miller, Richard A
Subject: RE: Macondo APB
Importance: Normal

Thanks Rich. This has been a crazy well for sure.

Mark

From: Miller, Richard A
Sent: Wednesday, April 14, 2010 6:03 PM
To: Morel, Brian P Cc: Hafle, Mark E
Subject: RE: Macondo APB

We have flipped design parameters around to the point that I got nervous. I did a rough update of both my disk calculations and my WellCat model. All looks fine. If we run the 9-7/8" x 7" as a long string, then the design resembles the original configuration, at least from an APB standpoint. The outward-acting 16" rupture disks mitigate 9-7/8" collapse loads due to B annulus APB. I do not have the final disk depth, so I guessed it is around 9,500'. If the
9-7/8" x 7" is run as a liner (per your schematic), then there is a risk that a trapped annulus forms between the 7" and 9-7/8" liners. The WellCat model predicts an incremental 2,350 psi APB in that annulus. To keep the 7" from collapsing, the pressure inside the 7" at 17,157' TVD needs to be 4,800 psi
or greater. Assuming that the production packer is set above this depth, then the 4,800 psi could dictate a reservoir abandonment pressure limit. We
can hash this out in the completion phase, but you may want to alert completions of that possible issue. Let me know if you have questions. I'll be in
Westlake Thursday morning and have an early afternoon flight to catch.

Rich

From: Morel, Brian P
Sent: Wednesday, April 14, 2010 1:31 PM
To: Miller, Richard A Cc: Hafle, Mark E
Subject: Macondo APB

Rich,

There is a chance we could run a production liner on Macondo instead of the planned long string. As this does not change much for APB based on the original design assumptions of a trapped annular, I don't see any major effects, but wanted to confirm I am not missing something. Attached is the proposed schematic, please let me know if you have any questions. We could be running it in 2-3 days, so need a relative quick response. Sorry for the late notice, this has been nightmare well which has everyone all over the place. Thanks
BP-HZN-CEC021857 Brian
Confidential BP-HZN-CEC021858

Courtesy of HuffingtonPost.com