** Shares of Australia's Beach Energy BPT.AX rise as much as 7.7% to A$1.4, its highest level since April 3
** Stock at its biggest intraday pct. gain since April 10
** Oil and gas explorer Vintage Energy VEN.AX says Beach Energy will buy 25% stake in its PEP 171 onshore basin in Victoria for A$1.25 million ($810,000.00)
** Around 9.4 mln shares change hands, 1.5x the 30-day average of 6.4 mln shares
** Session trims co's YTD losses to 6.8%
($1 = 1.5432 Australian dollars)
(Reporting by Shruti Agarwal in Bengaluru)
((Shruti.Agarwal@thomsonreuters.com;))