Vancouver, BC V6J 1X2

Tel 800 828 1866

TSX Symbol: PSH

Bulletin Board: PRRPF July 27, 2004

Mission River July 27th. update

Portrush Petroleum Corporation is pleased to announce an update from the Mission River Oilfield in the Gulf Coast region of Texas, near Corpus Christi, in Refugio County, Texas. Portrush has a 10% working interest in the project. Three wells have been completed, a fourth well has reached total depth, is awaiting completion and a fifth well will commence drilling this week. Several locations have been permitted and other possible locations are under evaluation.

The “Vicksburg age “Massive Sand” formation in this area has produced almost a billion barrels of oil and several TCF of gas since the field was first discovered in the nineteen thirties.

Scanio/Shelton Well No. 3

The well which has several prospective oil and gas horizons will be completed in the coming days. The operator has advised a service rig will be on this location on Wednesday July 28th.

This well was logged at a total dept of +6,800’. The operator removed sidewall cores and completed a pressure test from a number of prospective zones prior to completion. We have received excellent results from the sidewall core analysis.

Scanio/Shelton Well No. 2 & Scanio/Shelton Well No. 4

(on production, gas and condensate)

Both of these wells have been connected to the sales pipeline. The No.2 well has been on production for over a month. The No.4 well went on stream on July 20th.

Scanio/Shelton Well No. 5

This well reached total depth at 6,515’. Downhole wellbore surveys (“logs and sidewall cores) have been run. Multiple very good shows of oil and gas throughout interval 5,700’ - 6,515’. A decision to complete the well has been taken. The service rig will be moved on to this location as soon as work on No.3 is complete.

Information on the company can be obtained by calling (800) 828 1866 or at

www.portrushpetroleum.com

The company relies on litigation protection for “forward looking statements”.

ON BEHALF OF THE BOARD

/s/

M.Cotter

President

The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this release.