Oil firm Rock Well readies $500 mln UK IPO-sources

LONDON, July 7 (Reuters) - U.S. low-cost oil extraction firm Rock Well Petroleum on Monday announced a $300 million to $500 million London main board listing to tap investor interest in the sector at a time of rising oil prices.

The initial public offering, arranged by Numis (NUM.L: Quote, Profile, Research) and Merrill Lynch (MER.N: Quote, Profile, Research), is to be priced on July 16, with a market debut planned for July 21, people familiar with the matter said.

The company is offering shares at between 230 and 300 pence each, valuing the share sale at up to $500 million, the sources said.

By applying mining and drilling technologies to recover oil from matured fields, Rock Well has been able to lift its own reserves in North America to 322.5 million barrels from two million barrels. "Following the IPO, Rock Well will optimize the development of its existing assets, with over 320 million barrels of net proved and probable reserves, and further grow its reserve base through acquisition," said Chief Executive Officer John Hoak.

Rock Well acquired oil fields in Wyoming, Pennsylvania, Louisiana and Texas for about $54 million. These oil assets have an estimated pretax net present value of $3.735 billion, based on future cash flow of the company discounted at 10 percent, by independent engineers DeGolyer and MacNaughton.

With oil hitting a record $145.85 a barrel last week, analysts expect the sector to remain hot as countries look to replace production and reserves. Rock Well, which could break even at an oil price of $21 per barrel, projects an average weighted development cost of $4.47 per gross barrel and an operating cost of $3.55 per gross barrel for the first 10 years of production.

Rock Well has identified 250 onshore fields in North America and earmarked funds for acquiring 11 specific fields. (Reporting by Daisy Ku; Editing by Quentin Bryar)