Exhibit 10.4

AMENDMENT TO MANAGEMENT SERVICE AGREEMENT

This Amendment to Management Service Agreement (this “Amendment”), is entered
into effective August 5, 2010, (the “Effective Date”), by and between VIKING
DRLILLING, LLC, a Nevada limited liability company (“Viking”), whose address is
4801 Gaillardia Parkway, Suite 225, Oklahoma City, Oklahoma 73142, and VIKING
INTERNATIONAL LIMITED, a Bermuda company (“VIL”), whose registered address is
Canon’s Court, 22 Victoria Street, Hamilton HM 12 Bermuda.

RECITALS:

WHEREAS, Viking and VIL entered into that certain Agreement for Management
Services dated effective December 15, 2009 (the “Service Agreement”);

WHEREAS, Viking and VIL wish to amend the Service Agreement to replace the net
profits interest with a monthly management fee;

NOW, THEREFORE, in consideration of the mutual promises hereinafter set forth
and other good and valid consideration, the receipt and sufficiency of which are
hereby acknowledged, and subject to the terms and conditions hereof, the parties
hereto (collectively, the “Parties” and each individually a “Party”) agree as
follows:

1. Section 3 of the Service Agreement is deleted in its entirety and replaced
with the following:

“Payment. In consideration of the provision of Services under this Agreement,
VIL shall be entitled to payment from Viking for all actual costs and expenses
associated with the provision of Services. In addition, VIL shall be entitled to
a monthly management fee equal to seven percent (7.0%) of the total amount
invoiced for direct labor costs for employees of VIL providing Services pursuant
to this Agreement. Viking shall pay all invoices within thirty (30) days of
receipt unless Viking has disputed an invoice in writing. In the event of a
dispute, the parties shall work in good faith to resolve such dispute.”

2. Section 5 of the Service Agreement is hereby deleted in its entirety and all
sections subsequent to Section 4 are renumbered accordingly.

3. Except as modified and amended hereby, the Parties acknowledge and agree that
the Service Agreement remains in full force and effect.

IN WITNESS WHEREOF, the Parties have executed and delivered this Amendment as of
the Effective Date hereof.

 

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VIL:

 

Viking International Limited By:   /s/ Jeffrey S. Mecom Name:   Jeffrey S. Mecom
Its:   Vice President

VIKING:

 

Viking Drilling, LLC By:   /s/ N. Malone Mitchell, 3rd Name:   N. Malone
Mitchell, 3rd Its:   Manager

 

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