The Trinidad oil and gas firm is issuing 24.29mln new shares priced at 95p each to institutional and other investors in the United Kingdom and Canada.
Three successful exploration wells have so far been drilled at Ortoire - Coho, Cascadura and Chinook - and a fourth, Cascadura Deep, was spudded last week.
Funds raised in the placing will support the drilling of Cascadura Deep along with a planned fifth well, named Royston. Programmes are also slated for the completion, testing and development of the Chinook well. It will also pay for the installation of surface facilities at Cascadura.
"Following the significant exploration success at Ortoire, which has consistently exceeded our expectations, the placing will allow us to continue our exploration and development activities we have planned for the Ortoire block, as we seek to bring our existing natural gas discoveries onto production and drill further prospective targets,” said Paul Baay, Touchstone chief executive in a statement.
“We are delighted by the support we have received from new and existing investors. We continue to thank our shareholders for their ongoing support, and we look forward to continuing to update shareholders as the exploration program continues," he added.