Carrizo Drilling Ahead in Shale Plays

Carrizo Oil & Gas, Inc. provided an operational update on its Barnett Shale and Floyd Shale plays.

Carrizo has tested two additional Barnett Shale wells in the prolific "core" area of SE Tarrant Co., Tx. The Barton Hall Cecil #1H and #2H each tested at 4.2 MMCFED. Sales line connections are expected into an Energy Transfer pipeline in late July assuming no further rain delays. Four additional horizontal wells nearby in SE Tarrant Co. have been drilled and should be fracture stimulated in late July. Two additional SE Tarrant wells are currently being drilled. Carrizo has a 100% working interest in all of its SE Tarrant wells. The current drilling plan will utilize two drilling rigs dedicated to SE Tarrant for at least eighteen months with each rig drilling an estimated one horizontal well each month. Carrizo's third rig is splitting its time drilling horizontal wells in Tarrant, Parker and Hood Counties. The Company's fourth drilling rig is drilling horizontal wells in Parker and Hood Counties.

The frac and flow test program on the Miller A-14 well (in the "Mega-Mata Prospect") located in Matagorda Co., Tx. is essentially complete. Carrizo attempted a total of four fracture stimulations in the wellbore testing several zones. The first three intervals tested at rates between 0 and 800 MCFD with the final attempt (currently completed interval) testing at rates up to 3,200 MCFD and sustained a flow rate of only 1,500 MCFD with 8,300 psi over an extended test period. The gas stream contains 9% CO2 and 30 ppm H2S on average, which would require gas treatment facilities to produce. Profitability of further development and reserve potential are impacted by the nature of the gas stream and the low reservoir permeability and will be evaluated after an additional extended flow period. Carrizo has a 28% working interest and Petrobras has a 72% working interest.

Carrizo's first horizontal well in the Floyd Shale is being drilled in Clay Co., Miss. The well is currently at 8,274' and 83 degrees from vertical. The well was sidetracked last week after a drilling assembly was lost in the hole and could not be recovered. Current plans are to cement a liner in the hole once the curve is complete, and then drill a 3,000' lateral section. Fracture stimulation of three zones should begin in about eight weeks. Carrizo has a 50% working interest in the well.

The Company's estimated net production as of June 30, 2007 was 49 MMCFED with 28 MMCFED from the Barnett Shale and 21 MMCFE (net of an estimated 1.8 MMCFED for the shut-in of the Galloway GU 1 #2) from the Onshore Gulf Coast. The Galloway GU 1 #2, operated by Cimarex, was shut-in on May 6th due to a downhole mechanical failure and is under evaluation for a potential workover or sidetrack to restore production. We expect that the second quarter production will be in the range of 46 to 47 MMCFED as compared to our first quarter 2007 production of 35.6 MMCFED. This production increase from the first quarter 2007 is largely attributable to the new production in (1) the Barnett Shale from the three Campuzano wells, put on line in early May, and (2) the Onshore Gulf Coast from the Baby Ruth #1 and the Doberman #1 wells, put on line in mid-March and early May, respectively. In addition, an estimated 19 MMCFED net to Carrizo has been drilled and is waiting on completion and/or pipeline connection in the Barnett Shale including the previously mentioned SE Tarrant County wells.