Tri-Valley Gets Drill Funds for Big Oil and Gas Prospect.

Business Editors

BAKERSFIELD, Calif.--(BUSINESS WIRE)--June 23, 2003

Tri-Valley Corporation (OTCBB:TRIL) has secured well in excess of $4 million to fully fund drilling of its Oil Creek Prospect, for which it has just received its Fresno County permit and advance other prospects in its drilling program. The Company is completing the final Oil Creek drill permit details and expects to begin mobilizing to drill the exploratory well in July of this year.

The prospect is located near the City of Coalinga, Calif., and is surrounded by oilfields which have so far produced about two billion barrels of oil and nearly four trillion cubic feet of natural gas. While the Company notes that there is always the risk that the exploratory well could be a dry hole for any number of reasons, Tri-Valley estimates the aggregate potential of the six target (but as yet unproven) zones to be in the range of 125 million barrels of oil and 125 billion cubic feet of natural gas.

"We purposely choose very large targets where discovery success could provide exponential gains in cash flow and stock value and exceptionally reward our drilling partners who also receive substantial tax benefits. Also, discovery success of this magnitude can help consumers and the country," said F. Lynn Blystone, president and chief executive officer.

Blystone noted that Tri-Valley is launching the Oil Creek Prospect even as it is in the final stages this week of completing its Sunrise-Mayel No. 2HR test well with a 1 million pound hydraulic fracturing operation conducted by Dowell-Schlumberger for what the Company believes is an exceptionally large natural gas discovery at Delano, Calif.

No less a spokesperson than Alan Greenspan told Congress and the world a few days ago that the growing natural gas supply/demand imbalance is official and prices are headed higher and will hold there for some time. Tri-Valley believes the solution is discovery of new, flush production long life reserves and has assembled a portfolio of high impact California and Nevada exploration targets such as Sunrise and Oil Creek to hopefully begin to increase reserves and production.

"Tri-Valley is absolutely in the right place, at the right time, with the right commodities and the right program for investors to access this extraordinary opportunity. We know we'll have dry holes in the program but we've structured it to offer statistical probability of discovery success on a large scale. The fact that the oil price has doubled and gas prices have tripled the prices we originally used to assemble our drilling program offers our investors a bonanza premium on discovery success," Blystone said.

Tri-Valley is in its 40th year of business as an exploration and production company. It is a full reporting company currently traded over the counter on the electronic bulletin board under the symbol TRIL in the United States. Tri-Valley stock is also listed on the Berlin Stock Exchange under the symbol TVC WTN 911919. Tri-Valley Corporation and its wholly owned subsidiaries, Tri-Valley Oil & Gas Co. and Tri-Valley Power Co. are headquartered in Bakersfield, Calif., a premier petroleum producing province of the western hemisphere.

Our company website, which includes all SEC filings, is www.tri-valleycorp.com and www.tri-valley.de in Europe.

This press release contains forward-looking statements that involve risks and uncertainties. Actual results, events and performance could vary materially from those contemplated by these forward-looking statements which includes such words and phrases as exploratory, wildcat, prospect, speculates, unproved, prospective, very large, expect, potential, etc. Among the factors that could cause actual results, events and performance to differ materially are risks and uncertainties discussed in the company's quarterly report on Form 10-Q for the quarter ended March 31, 2003, and the annual report on Form 10-K for the year ended December 31, 2002.