Exhibit 10.2

AMENDMENT TO SERVICE AGREEMENT

This Amendment to Service Agreement (this “Agreement”), effective October 1,
2008, (the “Effective Date”), is by and among, TRANSATLANTIC PETROLEUM CORP., an
Alberta corporation, and its subsidiaries (“TransAtlantic”) and LONGFELLOW
ENERGY, LP, a Texas limited partnership, VIKING DRILLING, LLC, a Nevada limited
liability company, LONGE ENERGY LIMITED, a Bermuda limited liability company,
MEDOIL SUPPLY LLC, a Texas limited liability company, and RIATA MANAGEMENT, LLC,
an Oklahoma limited liability company, and their subsidiaries (collectively, the
“Riata Entities”).

RECITALS:

WHEREAS, TransAtlantic and the Riata Entities entered into that certain Service
Agreement dated effective May 1, 2008 (the “Service Agreement”) in connection
with TransAtlantic’s expanding scope of operations;

WHEREAS, TransAtlantic and the Riata Entities wish to amend the Service
Agreement to add MedOil Supply LLC as a party to the Service Agreement and to
clarify the purchase and transport of oilfield equipment and consumables by the
Riata Entities on behalf of and for the benefit of TransAtlantic as a service to
be provided;

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 1.01 of the Service Agreement is hereby amended by deleting
subsections (c) through (f) and replacing them with the following:

 

  “c. the purchasing and transportation of oilfield equipment and consumables;

   d. the provision of consultation with respect to debt and/or equity
financings;

   e. the documentation of domestic and international oil and gas transfers and
transactions;

   f. the preparation, review and negotiation of contracts; and

   g. the provision of such other services related to items (a) through (f) as
TransAtlantic or the Riata Entities may reasonably request and which the Party
providing the service has the capability to perform.”

2. MedOil Supply LLC, a limited liability company organized under the laws of
the State of Texas, is hereby added as a Party to the Service Agreement.

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 date first above written, to be effective, however, as of the Effective Date
hereof.

 

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TRANSATLANTIC:

 

TransAtlantic Petroleum Corp.

An Alberta Corporation

By:   /s/ Scott C. Larsen   Scott C. Larsen, President

RIATA ENTITIES:

 

Longfellow Energy, LP

A Texas limited partnership

By: Deut 8, LLC, Its General Partner

By:   /s/ Malone Mitchell, 3rd   Malone Mitchell, 3rd, Manager  

 

Viking Drilling, LLC

A Nevada limited liability company

By:   /s/ Malone Mitchell, 3rd   Malone Mitchell, 3rd, Manager  

 

Longe Energy Limited

A Bermuda limited liability company

By:   /s/ Malone Mitchell, 3rd   Malone Mitchell, 3rd, President  

 

Riata Management, LLC

An Oklahoma limited liability company

By:   /s/ Malone Mitchell, 3rd   Malone Mitchell, 3rd, Manager  

 

MedOil Supply, LLC

A Texas limited liability company

By:   /s/ Malone Mitchell, 3rd   Malone Mitchell, 3rd, Manager  

 

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