Exhibit 99.1

                      Gastar Exploration Updates
                           Canadian Filings


    HOUSTON--(BUSINESS WIRE)--September 18, 2007--Gastar Exploration
Ltd. (AMEX:GST) (TSX:YGA) said today that it has filed with the
Canadian System for Electronic Document Analysis and Retrieval (SEDAR)
revised forms related to its oil and natural gas reserves as of
December 31, 2006. The forms were revised to provide additional
information to ensure compliance with Canadian National Instrument
51-101, "Standards of Disclosure for Oil and Gas Activities", as
required by the Alberta Securities Commission and the Toronto Stock
Exchange. The revisions do not include any changes to Gastar's
previously reported reserves in any of the reserve categories nor will
the revised filings affect any of Gastar's filings with the U.S.
Securities and Exchange Commission. The Form 51-101F1, "Statement of
Reserves Data and Other Oil and Gas Information", revised Form
51-101F2, "Report of Reserve Data by Independent Qualified Reserves
Evaluator", and revised Form 51-101F3, "Report of Management and
Directors on Oil and Gas Disclosure" for the year ended December 31,
2006 can be found for viewing by electronic means on SEDAR at
www.sedar.com.

    The Company's filings comply with Canadian National Instrument
51-101 and contain natural gas and oil reserve information that would
not be permitted to be included in filings and reports made with
the United States Securities and Exchange Commission (SEC). The SEC
has generally permitted natural gas and oil companies, in their
filings made with the SEC, to disclose only proved reserves that a
company has demonstrated by actual production or conclusive formation
tests to be economically and legally producible under existing
economic and operating conditions. The Company's Canadian information
filings include estimates of probable reserves and reserves estimates
using forecast pricing and costs (as opposed to constant prices and
costs) that the SEC's guidelines may prohibit from inclusion in
filings with the SEC. These estimates are by their nature more
speculative than estimates of proved reserves and accordingly are
subject to substantially greater risk of being actually realized by
the Company. The information included in the Canadian filings related
to estimates of proved reserves of the Company as of December 31, 2006
using constant prices and costs and related future net revenues and
estimates of production for the year ended December 31, 2007 are based
on the estimates of proved reserves as of December 31, 2006, as
previously reported in the Company's Annual Report on Form 10-K for
the year ended December 31, 2006 filed with the SEC.

    Gastar Exploration Ltd. is an exploration and production company
focused on finding and developing natural gas assets in North America
and Australia. The Company pursues a strategy combining select higher
risk, deep natural gas exploration prospects with low-risk coal bed
methane (CBM) development. The Company owns and operates exploration
and development acreage in the deep Bossier gas play of East Texas.
Gastar's CBM activities are conducted within the Powder River Basin of
Wyoming and upon the approximate 3.0 million gross acres controlled by
Gastar and its joint development partners in Australia's Gunnedah
Basin (PEL 238), located in New South Wales, and Gippsland Basin (EL
4416), located in Victoria.

    Safe Harbor Statement and Disclaimer

    This news release includes "forward-looking statements" within the
meaning of Section 27A of the Securities Act of 1933 and Section 21E
of the Securities Act of 1934. A statement identified by the words
"expects", "projects", "plans", and certain of the other foregoing
statements may be deemed forward-looking statements. Although Gastar
believes that the expectations reflected in such forward-looking
statements are reasonable, these statements involve risks and
uncertainties that may cause actual future activities and results to
be materially different from those suggested or described in this news
release. These include risks inherent in the drilling of natural gas
and oil wells, including risks of fire, explosion, blowouts, pipe
failure, casing collapse, unusual or unexpected formation pressures,
environmental hazards, and other operating and production risks
inherent in the natural gas and oil drilling and production
activities, which may temporarily or permanently reduce production or
cause initial production or test results to not be indicative of
future well performance or delay the timing of sales or completion of
drilling operations, risks with respect to natural gas and oil prices,
a material decline in which could cause the Company to delay or
suspend planned drilling operations or reduce production levels, and
risks relating to the availability of capital to fund drilling
operations that can be adversely affected by adverse drilling results,
production declines and declines in natural gas and oil prices and
other risk factors described in the Company's Annual Report on Form
10-K, as filed on March 27, 2007 with the SEC at www.sec.gov and on
the System for Electronic Document Analysis and Retrieval (SEDAR) at
www.sedar.com.

    The American Stock Exchange and the Toronto Stock Exchange have
not reviewed and do not accept responsibility for the adequacy or
accuracy of this news release.


    CONTACT: Gastar Exploration Ltd.
             Vice President and CFO
             Michael Gerlich, 713-739-1800
             mgerlich@gastar.com
             or
             Investor Relations Counsel:
             DRG&E
             Lisa Elliott, 713-529-6600
             lelliott@drg-e.com
             or
             Anne Pearson, 713-529-6600
             apearson@drg-e.com