Filed by Unocal Corporation
                           Pursuant to Rule 425 under the Securities Act of 1933
                                           Subject Company: Pure Resources, Inc.
                                                   Commission File No. 001-15899

                                                          Dated: October 9, 2002



     Unocal enters into agreement with Pure Resources management; increases
            exchange ratio to 0.74 Unocal shares for each Pure share

El Segundo, Calif., Oct. 9, 2002 -- Unocal Corporation (NYSE: UCL) today said
that it has entered into an agreement with the senior management of Pure
Resources, Inc. (NYSE: PRS) providing for their support of Unocal's pending
exchange offer for the shares of Pure common stock not currently owned by
Unocal.

In accordance with the agreement, Unocal's Union Oil Company of California
subsidiary is increasing the exchange ratio of the exchange offer to 0.74 shares
of Unocal common stock for each share of Pure's common stock.  Unocal has been
informed by the special committee of the Pure board of directors that the
committee will recommend that Pure stockholders accept the increased offer and
tender their shares.

The members of Pure's senior management have agreed to tender all their
outstanding shares into the exchange offer and to relinquish, without payment of
additional consideration, the put rights that cover a total of 2,796,959
currently outstanding shares and options to acquire an additional 4,100,584 Pure
shares. The 2,796,959 currently outstanding Pure shares that are subject to the
agreement represent approximately 5.5 percent of Pure's outstanding shares.  In
addition, Unocal has agreed that it will not waive the condition to the offer
that a sufficient number of Pure shares are tendered to result in Union Oil
owning at least 90 percent of Pure's outstanding common stock.

Unocal will file amended  offering  documents with the U.S.  Securities and
Exchange Commission shortly.  The exchange offer will be extended to remain open
for 10 business days from the date of the  amendment and will remain subject to
the  conditions  included in the offer as amended on Oct. 3, 2002.  Unocal said
that the increased  exchange ratio of 0.74 represents the highest and best offer
that Unocal will make for the Pure shares.

Unocal also  reported  that it has been advised by the depositary for the
exchange offer that, as of Oct. 8, 2002, the number of Pure shares that have
been tendered and not withdrawn is 467,137.

ADDITIONAL INFORMATION
A prospectus, which is part of the Unocal Registration Statement on Form S-4,
and related exchange offer materials, including a letter of transmittal, has
been mailed to stockholders of Pure. Investors and stockholders of Pure are
urged to read all of these documents carefully and the Amended Registration
Statement and Schedule TO when they become available. These documents contain
important information about the transaction and should be read in connection
with making a decision with respect to the exchange offer. Unocal has filed its
Registration Statement on Form S-4 and a Schedule TO with the Securities and
Exchange Commission (SEC). Investors and stockholders are able to obtain free
copies of these documents through the SEC's web site, www.sec.gov. For
additional information on the exchange offer or copies of any of the offering
materials, stockholders may contact D.F. King & Co., Inc., at 800-769-6414. In
addition, Merrill Lynch is the dealer-manager for the exchange offer and may be
contacted at 866-276-1462.

In addition to the amended Registration Statement on Form S-4, Schedule TO,
prospectus and related exchange offer materials, both Unocal and Pure file
annual, quarterly and special reports, proxy statements and other information
with the SEC. You may read and copy any reports, or other information filed by
Unocal or Pure at the SEC public reference room at 450 Fifth Street, NW,
Washington, D.C. 20549, or at any of the SEC's other public reference rooms in
New York City, N.Y., and Chicago, Ill. Please call the SEC at 800-SEC-0330 for
further information on the public reference rooms. The SEC filings by Unocal and
Pure are also available to the public from commercial document-retrieval
services and at the SEC web site.

ABOUT UNOCAL CORPORATION
Unocal is one of the world's largest independent natural gas and crude oil
exploration and production companies. Based in El Segundo, Calif., Unocal's
principal production operations are in North America, Asia, and the North Sea.
Unocal is also one of the world's largest producers of geothermal energy with
operations in Indonesia and the Philippines.

ABOUT PURE RESOURCES, INC.
Pure is an independent exploration and production company that develops and
produces oil and natural





gas in the Permian Basin, the San Juan Basin, the Gulf Coast and the Gulf
of Mexico.  The company also owns an undivided interest under approximately 6
million gross fee mineral acres throughout the Southern Gulf Coast region of the
U.S. Pure was formed in May 2000 through the combination of Titan Exploration,
Inc., and the Permian Basin business unit of Unocal Corporation.
                                  * * * * *
This news release contains certain forward-looking statements about future
business transactions involving Unocal and Pure. These statements are not
guarantees of future performance and involve certain risks and uncertainties
that are difficult to predict. The statements are based upon Unocal's current
expectations and beliefs and are subject to a number of known and unknown risks
and uncertainties that could cause actual results to differ materially from
those described in the forward looking statements. Actual results could differ
materially from what is expressed or forecasted in this news release. Those risk
factors are discussed in the Unocal and Pure Annual Reports on Form 10-K, in
each case as amended, and subsequent reports that have been filed by the
companies with the U.S. Securities and Exchange Commission.

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