(Bloomberg) Colombia, South America’s third- largest oil supplier, plans to attract investment in new crude reserves and so-called unconventional energy deposits with its first government auction of blocks in two years.

Units of Royal Dutch Shell Plc (RDSA), Exxon Mobil Corp. (XOM) and state-controlled Ecopetrol SA are among companies that have pre- qualified to bid today on 115 blocks, including more than two dozen areas holding oil and natural gas trapped in shale rock, according to the website of the National Hydrocarbons Agency. Companies will submit proposals from about 9 a.m. Bogota time with preliminary results released during the day.

Colombia needs to find new reserves to ensure future increases in oil production that jumped 72 percent since 2007 as improved security drew record international investment. The nation’s reserves of about 2.3 billion barrels are equivalent to almost seven years of output, lagging reserves of smaller producers Ecuador and Argentina, U.S. government figures show.

“Seven years is a relatively small amount for a country that depends a lot on oil,” Juan David Pineros, an analyst at the nation’s largest brokerage, Interbolsa SA, said yesterday in a telephone interview from Medellin, Colombia. “It’s a big step to ensure future reserves.”
Shale Investments

Blocks will be awarded based on proposals for investment and the government’s share of production. Companies that have qualified to bid also include units of Brazil’s Petroleo Brasileiro SA (PETR4) and OGX Petroleo e Gas Participacoes SA, the government said last month. Rio de Janeiro-based Petrobras and OGX didn’t immediately respond to e-mails seeking comment.

The country will award rights to blocks covering about 13.5 million hectares (33.4 million acres) across mountainous central Colombia, its eastern plains and offshore in the Caribbean, according to Bogota-based National Hydrocarbons Agency.

The auction may draw $500 million in investment to unconventional reserves, the government said in March. Ecopetrol (ECOPETL), Colombia’s largest oil company, already is seeking partners to drill for the fuels.

A surge in production of unconventional energy in the U.S. is leading companies to search for new sources overseas, Pineros said. Production and reserves of U.S. shale natural gas more than quadrupled in 2010 from 2007, according to the website of the U.S. Energy Information Administration.

Patrick McGinn, a Houston-based spokesman for Exxon, declined to comment on the auction in an e-mail yesterday. Kelly OpDeWeegh, a Houston-based U.S. media relations officer for Shell, said the company is evaluating its participation, in an e-mail yesterday.
Million-Barrel Target

Colombia expects to produce more than 1 million barrels a day of crude at the end of December, Energy and Mines Minister Federico Renjifo said last week. Output was 956,300 barrels a day in September.

Venezuela and Brazil are South America’s largest oil producers. Ecuador and Argentina surpass Colombia in crude reserves, with 6.5 billion barrels and 2.5 billion barrels, respectively, according to figures from the U.S. Energy Information Administration.