Carrizo Oil & Gas Says Year-End 2003 Proved Reserves Up 11%

Carrizo Oil & Gas, Inc. reports that 2003 year-end proved reserves were a record 70.4 Bcfe based on reports from its third-party reserve engineers. This is an increase of eleven percent over the year-end 2002 proved reserves of 63.2 Bcfe. Proved developed reserves at year-end 2003 increased 20.2 percent versus year-end 2002 to 25.5 Bcfe and proved undeveloped reserves increased 6.8 percent to 44.9 Bcfe. These additions resulted in the Company replacing 196 percent of 2003 production.