Tri-Valley Corp. (TIV) Completes Expanded Phase 1 Claflin Drilling Program

Apr. 28, 2011 (Business Wire) — Tri-Valley Corporation (NYSE Amex: TIV) today announced that it has completed an expanded Phase 1 development drilling program at its Claflin oil project, located in the Edison Oil Field near Bakersfield, California. The Company has drilled eight new wells, up from the six wells initially planned. These new wells are part of Tri-Valley’s overall plan to drill a total of 22 new wells at Claflin during 2011 to convert 2.1 million barrels of net proved undeveloped oil reserves (“PUDs”) on the property to proved developed and producing (“PDP”) status and to increase oil production. The net proved undeveloped reserves were included in the reserves disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2010, and filed with the U.S. Securities and Exchange Commission on March 22, 2011.

Tri-Valley is currently completing the installation of well-site production equipment and tie-in of the new wells to existing production facilities at Claflin. The Company expects to commence an initial steam injection cycle on the first well in early May and that the new wells will have received an initial steam injection cycle by the end of July; however, new steam generating capacity being installed at Claflin could accelerate completion of this initial steam injection work on the new wells. First oil production is anticipated from some of the new wells by June. Following first production from these new wells, there will be a 90-day evaluation period during which Tri-Valley will analyze the performance of the new wells prior to commencement of the second phase of the Claflin development to complete the remaining 14 new wells by the end of the year.

“We are ahead of schedule on our plans to develop the Claflin property to drive increased oil production in 2011,” said Maston N. Cunningham, President and CEO of Tri-Valley Corporation. “Our plan calls for a total of 13 new vertical wells and nine new horizontal wells to be drilled on the property this year. If we are successful, we expect to exit 2011 with gross daily production of about 800 barrels of oil from the property.”

“With the closing of our recent private placement financing, we raised nearly five million dollars in new capital that will allow us to pursue our development plans at Claflin,” continued Mr. Cunningham. “We would like to welcome Ironman Energy Master Fund, an experienced oil and gas investment fund and major participant in our recent financing, as a significant new shareholder of Tri-Valley Corporation.”

“Negotiations with adjacent land and mineral owners to secure permits for the 3-D seismic acquisition area for the Claflin and adjoining Brea properties have taken more time than originally planned, but we believe that seismic acquisition work should start by the end of May,” added Mr. Cunningham. “This new 3-D data will useful for our exploitation plans for Claflin and Brea, including better geologic control during horizontal drilling operations later this year in the second phase of Claflin development.”

About Tri-Valley

Tri-Valley Corporation explores for and produces oil and natural gas in California and has two exploration-stage gold properties in Alaska. Tri-Valley is incorporated in Delaware and is publicly traded on the NYSE Amex exchange under the symbol “TIV.” Our Company website, which includes all SEC filings, is www.tri-valleycorp.com.

Forward-Looking Statements

All statements contained in this press release that refer to future events or other non-historical matters are forward-looking statements. By way of example, statements contained in this press release related to the expected timeline for well-drilling completion, first oil production, installation of facility upgrades and seismic study results, as well as the anticipated number of wells to be drilled, gross barrel production and production rates, and such other future events, business plans and objectives of management for future operations, are forward-looking statements. Although the Company does not make forward-looking statements unless it believes it has a reasonable basis for doing so, the Company cannot guarantee their accuracy. These statements are only predictions based on management’s expectations as of the date of this press release, and involve known and unknown risks, uncertainties and other factors, including: the Company’s ability to obtain additional funding; imprecise estimates of oil reserves; drilling hazards such as equipment failures, fires, explosions, blow-outs, and pipe failure; shortages or delays in the delivery of drilling rigs and other equipment; problems in delivery to market; adverse weather conditions; compliance with governmental and regulatory requirements; fluctuations in oil prices; and such other risks and factors that are discussed in the Company’s filings with the Securities and Exchange Commission from time to time, including under “Item 1A. Risk Factors” and “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations,” contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2010. Except as required by law, the Company undertakes no obligation to update or revise publicly any of the forward-looking statements after the date of this press release to conform such statements to actual results or to reflect events or circumstances occurring after the date of this press release.