Note Regarding Forward-Looking Statements

This Form 10-Q includes "forward-looking statements" within the meaning of
Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical facts included in this Form 10-Q, including without limitation the statements under "Management's Discussion and Analysis of Financial Condition and Results of Operations" are forward-looking statements. No assurance can be given that such expectations will prove to have been correct. When used in this Form 10-Q, the words "believes," "expects," "anticipates," "projects," "intends" or similar expressions are intended to identify such forward-looking statements. The following important factors, in addition to those discussed elsewhere in this Form 10-Q, could affect the future results of the energy industry in general, and Whiting Petroleum Corporation ("Whiting") and Whiting USA Trust I (the "Trust") in particular, and could cause actual results to differ materially from those expressed in such forward-looking statements:

• the effect of changes in commodity prices and conditions in the capital markets;

• uncertainty of estimates of oil and natural gas reserves and production;

• risks incident to the operation of oil and natural gas wells;

• future production costs;

• the inability to access oil and natural gas markets due to market conditions or operational impediments;

• failure of the underlying properties to yield oil or natural gas in commercially viable quantities;

• the effect of existing and future laws and regulatory actions;

• competition from others in the energy industry;

• risks arising out of the hedge contracts;

• inflation or deflation;

• the effects of global credit, financial and economic issues; and

• other risks described under the caption "Risk Factors" in this Form 10-Q.

All subsequent written and oral forward-looking statements attributable to the Trust or persons acting on its behalf are expressly qualified in their entirety by these factors. The Trust assumes no obligation, and disclaims any duty, to update these forward-looking statements.

Overview

The following review of the Trust's financial condition and results of operations should be read in conjunction with the financial statements and notes thereto. The Trust was formed on October 18, 2007. The conveyance of the NPI however, did not occur until April 30, 2008. As a result, the Trust did not recognize any income or make any distributions during 2007 or during the first quarter of 2008. The NPI was conveyed effective for production from the underlying properties starting from January 1, 2008. Therefore, the Trust's first quarterly distribution paid on

May 30, 2008 consisted of an amount in cash paid by Whiting equal to the amount that would have been paid to the Trust had the conveyance been in place since the January 1, 2008 effective date through March 31, 2008.

The Trust does not conduct any operations or activities. The Trust's purpose is, in general, to hold the NPI, to distribute to the Trust unitholders cash that the Trust receives in respect of the NPI and to perform certain administrative functions in respect of the NPI and the Trust units. The Trust derives substantially all of its income and cash flows from the NPI, which is in turn subject to commodity hedge contracts.

Distributable Income

Nine months ended September 30, 2008. For the nine months ended September 30, 2008, the Trust's distributable income was $35,539,606 and was based on income from net profits interest of $36,325,105 less general and administrative expenses of $549,422, cash withheld for future Trust expenses of $122,916, and Montana state income tax withholdings of $235,499, which were partially offset by cash reserves used for current Trust expenses of $122,338.

Three Months Ended September 30, 2008. For the three months ended September 30, 2008, the Trust's distributable income was $21,156,745 and was based on income from net profits interest of $21,546,068 less general and administrative expenses of $372,338, and Montana state income tax withholdings of $139,323 , which were partially offset by cash reserves used for current Trust expenses of $122,338.

Income from Net Profits Interest

Nine months ended September 30, 2008. For nine months ended September 30, 2008, the Trust recognized income from net profits interest of $36,325,105. Included in this amount is a deduction of $86,081 (90% of $95,646) for cash settlements paid under commodity derivative contracts from April 1, 2008 through June 30, 2008. As the NPI was conveyed effective for production from the underlying properties beginning January 1, 2008, income from net profits interest for the nine months ended September 30, 2008 consisted of an amount paid to the Trust by Whiting equal to the amount that would have been payable to the Trust had the conveyance been in place since the January 1, 2008 effective date through September 30, 2008.

As publicly reported, SemCrude, LP and its affiliates (collectively, "SemCrude") filed bankruptcy Chapter 11 petitions on July 22, 2008 in Delaware Bankruptcy Court. SemCrude purchased certain crude oil produced from a portion of the properties subject to the NPI held by the Trust and failed to pay for such purchases during the month of June 2008 and the first 22 days of July 2008, which had the effect of reducing income from net profits by approximately $270,000 for the nine months ended September 30, 2008.

Income from net profits interest is recorded on a cash basis when NPI proceeds are received by the Trust from Whiting. During the nine months ended September 30, 2008, the Trust received two NPI remittances from Whiting, a May 2008 and an August 2008 NPI distribution. NPI net proceeds that Whiting remits to the Trust are based on the oil and gas production Whiting has received payment for within one month following the end of the most recent fiscal quarter. Whiting receives payment for its crude oil sales generally within 30 days following the month in which it is produced, and Whiting receives payment for its natural gas sales generally within 60 days following the month in which it is produced. Accordingly, income from net profits interest for the nine months ended

September 30, 2008 (consisting of Whiting's May 2008 and August 2008 NPI remittances to the Trust) generally represents crude oil sales for January through June of 2008 and natural gas sales for January through May of 2008.

Three Months Ended September 30, 2008. For the three months ended September 30, 2008, the Trust recognized income from net profits interest of $21,546,068. Included in this amount is a deduction of $86,081 (90% of $95,646) for cash settlements paid under commodity derivative contracts from April 1, 2008 through June 30, 2008. Income from net profits interest is recorded on a cash basis when NPI proceeds are received by the Trust from Whiting. During the three months ended September 30, 2008, the Trust received one NPI remittance from Whiting in August of 2008. NPI net proceeds that Whiting remits to the Trust are based on the oil and gas production Whiting has received payment for within one month following the end of the most recent fiscal quarter. Whiting receives payment for its crude oil sales generally within 30 days following the month in which it is produced, and Whiting receives payment for its natural gas sales generally within 60 days following the month in which it is produced. Accordingly, income from net profits interest for the three months ended September 30, 2008 (consisting of Whiting's August 2008 NPI remittance to the Trust) generally represents crude oil sales for April, May and June of 2008 and natural gas sales for March, April and May of 2008.

As publicly reported, SemCrude filed bankruptcy Chapter 11 petitions on July 22, 2008 in Delaware Bankruptcy Court. SemCrude purchased certain crude oil produced from a portion of the properties subject to the NPI held by the Trust and failed to pay for such purchases during the first 22 days of July 2008, which had the effect of reducing income from net profits by approximately $130,000 for the three months ended September 30, 2008.

Income from net profits interest is generally affected by three major factors:

• oil and gas sales volumes,

• oil and gas sales prices, and

• costs deducted in the calculation of income from net profits interest.

The following is a summary of income from net profits interest received by the Trust for the three and nine month periods ended September 30, 2008:

                                                       Three Months Ended          Nine Months Ended
                                                       September 30, 2008         September 30, 2008

Sales Volumes:
Oil from underlying properties (Bbls)                              234,986 (a)                439,010 (c)
Natural gas from underlying properties (Mcf)                       998,476 (b)              1,788,331 (d)
Average Sales Prices:
Oil (per Bbl)                                         $             103.93        $             96.02
Natural gas (per Mcf)                                 $               8.86        $              8.19
Costs (per BOE):
Lease operating expenses                              $              17.18        $             16.69
Production taxes                                      $               5.82        $              5.48
Cash settlements paid under commodity derivative
contracts                                             $               0.24        $              0.13
Revenues:
Oil sales                                             $         24,423,282 (a)    $        42,155,092 (c)
Natural gas sales                                                8,844,908 (b)             14,640,784 (d)

Total revenues                                        $         33,268,190        $        56,795,876

Costs:
Lease operating expense                               $          6,896,759        $        12,301,866
Production taxes                                                 2,335,709                  4,037,136
Hedge settlements                                                   95,646                     95,646

Total costs                                           $          9,328,114        $        16,434,648

Net proceeds                                          $         23,940,076        $        40,361,228

Net profits percentage                                                  90 %                       90 %

Income from net profits interest                      $         21,546,068        $        36,325,105

(a) Because of the one-month interval between the time crude oil volumes are produced and the receipt of oil sales proceeds by Whiting, oil volumes and sales for the three months ended September 30, 2008 (consisting of Whiting's August 2008 NPI remittance to the Trust) generally represent crude oil production for April, May and June of 2008.

(b) Because of the two-month interval between the time natural gas volumes are produced and the receipt of gas sales proceeds by Whiting, natural gas volumes and sales for the three months ended September 30, 2008 (consisting of Whiting's August 2008 NPI remittance to the Trust) generally represent gas production for March, April and May of 2008.

(c) Because of the one-month interval between the time crude oil volumes are produced and the receipt of oil sales proceeds by Whiting, oil volumes and sales for the nine months ended September 30, 2008 (consisting of Whiting's May 2008 and August 2008 NPI distributions to the Trust) generally represent crude oil production from January through June of 2008.

(d) Because of the two-month interval between the time natural gas volumes are produced and the receipt of gas sales proceeds by Whiting, natural gas volumes and sales for the nine months ended September 30, 2008 (consisting of Whiting's May 2008 and August 2008 NPI distributions to the Trust) generally represent gas production from January through May of 2008.

Liquidity and Capital Resources

The Trust has no source of liquidity or capital resources other than cash flows from the NPI. Other than Trust administrative expenses, including any reserves established by the Trustee for future liabilities, the Trust's only use of cash is for distributions to Trust unitholders. Administrative expenses include payments to the Trustee as well as a quarterly administrative fee to Whiting pursuant to an administrative services agreement. Each quarter, the Trustee determines the amount of funds available for distribution. Available funds are the excess cash, if any, received by the Trust from the NPI, subject to the hedge contracts, and other sources (such as interest earned on any amounts reserved by the Trustee) that quarter, over the Trust's liabilities for that quarter. Available funds are reduced by any cash the Trustee decides to hold as a reserve against future liabilities. The Trustee may borrow funds required to pay liabilities if the Trustee determines that the cash on hand and the cash to be received are insufficient to cover the Trust's liability. If the Trustee borrows funds, the Trust unitholders will not receive distributions until the borrowed funds are repaid.

Income to the Trust from the NPI is based on the calculation and definitions of "gross proceeds" and "net proceeds" contained in the conveyance, the form of which is filed as an exhibit to this report, and reference is hereby made to the conveyance for the actual definitions of "gross proceeds" and "net proceeds".

The Trust does not have any transactions, arrangements or other relationships with unconsolidated entities or persons that could materially affect the Trust's liquidity or the availability of capital resources.

Future Trust Distributions to Unitholders

On November 12, 2008, the Trustee announced the Trust distribution of net profits for the third quarterly payment period in 2008. Unitholders of record on November 19, 2008 are expected to receive a distribution amounting to $21,440,718 or $1.546515 per Trust unit, which is expected to be paid on November 28, 2008. This distribution is expected to consist of net cash proceeds of $21,956,419 paid by Whiting to the Trust, which includes a deduction of $72,273 (90% of $80,303) for cash settlements paid under commodity derivative contracts from July 1, 2008 through September 30, 2008, less a provision of $375,000 for estimated Trust expenses and $140,701 for Montana state income tax withholdings.

As publicly reported, SemCrude filed bankruptcy Chapter 11 petitions on July 22, 2008 in Delaware Bankruptcy Court. SemCrude purchased certain crude oil produced from a portion of the properties subject to the NPI held by the Trust and failed to pay for such purchases during the month of June 2008 and the first 22 days of July 2008, having the effect of reducing the Trust's earnings by approximately $270,000 for the nine months ended September 30, 2008. Whiting will file appropriate claims in the bankruptcy proceedings with respect to this outstanding amount, but recovery on this receivable, if any, will depend on the bankruptcy process governing SemCrude. Whiting has continued to sell production from the affected properties to SemCrude after July 22, 2008 on a cash prepayment basis.