Rio Vista Energy Partners Provides Operational Update and Provides Company Overview...

Rio Vista Energy Partners Provides Operational Update and Provides Company Overview in Regulatory Filing

BROWNSVILLE, Texas--(Business Wire)--
Rio Vista Energy Partners L.P. (NASDAQ: RVEP), an energy services
master limited partnership focused on the development of oil and gas
properties in Oklahoma and the terminalling and transportation of bulk
chemical and petroleum products in Virginia, today announced that it
has filed a presentation regarding the Company's recent acquisitions
and business operations in a regulatory filing made with the
Securities and Exchange Commission on Form 8-K. Rio Vista intends to
make this presentation available on its website in the near future
(www.riovistaenergy.com).

In addition, the Company today provided an interim operations
update.

Management Comments

Ian Bothwell, Rio Vista's Acting Chief Executive Officer said,
"Good progress is being made in both the development of the recently
acquired oil and gas assets in Oklahoma and the expansion of new
contracts and growth opportunities in our terminalling and
transportation business in Virginia. A number of projects on our
Oklahoma assets are well under way, including infrastructure
improvements and additions, existing well tie-ins, workovers and new
drilling. A large drilling program is currently being organized for
2008 to continue to develop both the shallow Booch sand and the
Hartshorne Coal. We are anticipating a significant increase in our
production from these assets as a result of this activity. In
addition, we have been actively pursuing new contracts and growth
opportunities for our Virginia operations and continue to be excited
about the revenue growth anticipated from this activity. We continue
to evaluate new assets for acquisition and look forward to success in
this area much like we experienced in 2007."

Operations Update

Oklahoma

-- A pipeline was laid to tie an existing well, the Groseclose
2V-17 (100% Working Interest), adding 100 mcfd of gross
production.

-- A pipeline was laid in the Brooken Field to bypass an existing
pipeline thereby reducing back pressure on the area.
Additionally, this new interconnection has decreased Rio
Vista's transportation cost in the Brooken Field.

-- Rio Vista Operating LLC has taken over operations of the
Oklahoma producing properties.

-- Concorde Resources has recently drilled a successful coal bed
methane well (Chaffin 1-26) on joint acreage with Rio Vista
(Working Interest 25%). The well has been completed and is
currently testing.

-- The Belt 2V-24 (Working Interest 34%) has been deepened and
logged in the Savannah Sand. The well has been frac stimulated
and tested. The gas pipeline interconnection will be completed
during April 2008.

-- The Cannon 1-31 (deep test in the Crouch Field) has been
drilled and cased. Openhole logs confirm the existence of
multiple productive zones. Completion of this well began in
March.

-- The Donna 1 (vertical Hartshorne Coal in the Brooken Field)
has been drilled and cased. The completion of this well will
begin in early April 2008. Rio Vista will have an 80% Working
Interest in this well.

-- The Tom 1 (vertical Hartshorne Coal in the Brooken Field) has
been drilled and cased. The well has also been perforated and
is currently being tested. Rio Vista will have an 80% Working
Interest in this well.

-- The ACE #2-36 (horizontal Hartshorne Coal in the Canadian
Field) will spud in early April. Rio Vista has a 51% Working
Interest in this well.

Regional

-- Recently contracted with an existing customer for additional
terminalling and transportation. The contract term is for 5
years and is expected to provide increases in both
terminalling and hauling revenues.

-- Recently contracted with other customers for transportation
services. Contracts range from 1 year to 2 years and are
renewable thereafter. Contracts are expected to provide
increases in both terminalling and hauling revenues.

-- Recently registered with the US Government Central Contractor
data base with status as a small business contractor and
vendor capable of storing and hauling bulk chemical and
petroleum products. Such registration allows Regional to bid
for government contracts within the Department of Defense and
the Defense Energy Support Center and any other applicable
agency. Regional's operations are strategically located near
many significant military facilities (army and navy). Regional
expects that this registration will provide opportunities for
significant additional revenues.

-- Since ownership of Regional, Regional's plant and hauling
operations have been operating more efficiently, with
increased driver utilization during the forth quarter of 2007.

-- Regional's current "Safestat" number is 14.6 which is
considerably lower than the average of Regional's competitors
of approximately 35.3. "Safestat" is a numerical grading
system that is administered by the US Department of
Transportation. It considers factors such as roadside DOT
inspections, traffic citations, etc. and is relied upon by
insurance companies, state police, DOT, competitors, and
potential customers in grading Regional.

About Rio Vista Energy Partners L.P.

Rio Vista is a master limited partnership focused primarily on
acquiring and developing oil and gas exploration, production and
transportation assets. Through its subsidiaries, Rio Vista currently
owns certain leasehold interests of oil and gas producing properties
and associated pipeline gathering systems in East Central Oklahoma.
Rio Vista is also engaged in liquid bulk storage, transloading and
transportation of chemicals and petroleum products through its assets
and operations in Hopewell, Virginia. Rio Vista seeks to grow
primarily through the acquisition of qualified oil and gas assets.
Penn Octane Corporation (OTCBB: POCC) owns 75% of Rio Vista GP LLC,
the general partner of Rio Vista.

Forward-Looking Statements

Certain of the statements in this news release are forward-looking
statements, including statements regarding the operation status of Rio
Vista's oil and gas properties, including future production of oil and
gas from Rio Vista's properties in East Central Oklahoma and the
liquid bulk storage, transloading and transportation of bulk chemicals
and petroleum business in Hopewell, Virginia. Although these
statements reflect Rio Vista's beliefs, they are subject to
uncertainties and risks that could cause actual results to differ
materially from expectations. The acquisition of the properties in
East Central Oklahoma may not prove successful and has substantially
increased Rio Vista's and its subsidiaries' indebtedness and
contingent liabilities, and may present integration difficulties.
Continuation and expansion of production may require unforeseen
capital investment. Future production may be lower than anticipated,
and actual natural gas reserves may prove lower than estimated. If Rio
Vista does not receive sufficient revenues from the use of its assets,
Rio Vista would suffer material adverse consequences to its business,
resulting in reduced cash available for distributions. Rio Vista's
credit facility with TCW prohibits distributions by Rio Vista's
Oklahoma subsidiaries during the first 12 months of the credit
facility and limits those distributions to 75% of defined available
cash flow thereafter. As a result, Rio Vista may not have sufficient
available cash to pay minimum quarterly distributions. In addition,
Rio Vista may not distribute sufficient cash to meet the tax
obligations of unitholders associated with the ownership of common
units. If Rio Vista does not have sufficient capital resources for
acquisitions or opportunities for expansion, Rio Vista's growth will
be limited. Rio Vista may be unable to complete future acquisitions of
qualified oil and gas assets or other transactions and, even if
completed, acquisitions may not prove successful. Additional
information regarding risks affecting Rio Vista's business may be
found in Rio Vista's most recent reports on Form 8-K, Form 10-Q and
Form 10-K and its registration statement on Form S-3 filed with the
Securities and Exchange Commission on February 13, 2008, and in Penn
Octane Corporation's most recent reports on Form 8-K, Form 10 Q and
Form 10-K filed with the Securities and Exchange Commission.

Rio Vista Energy Partners L.P.
Ian T. Bothwell, 760-772-9080
or
CEOcast, Inc.
Gary Nash, 212-732-4300

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