Workover Operations Commence in Wincher Range Gas Field in EP 408

San Francisco-based GeoPetro Resources Company (GeoPetro or the Company) reported Tuesday that CalEnergy Resources (Australia) Ltd. and Whicher Range Energy Pty Ltd. have commenced workover operations in the Whicher Range Gas Field, Whicher Range Permit, Exploration Permit (EP) 408 located approximately 174 miles (280 kilometers) south of Perth, Western Australia. GeoPetro has retained an economic interest in the EP 408 Permit. This permit contains the Whicher Range gas field which was discovered in 1968.

The Whicher Range structure is a large gas field. Seismic data and the drilling of five exploration/appraisal wells have defined the field with a gross hydrocarbon column height of 2,133 feet (650 meters) and a potential gas resource in place in excess of 4 trillion cubic feet.

CalEnergy Resources (Australia) Ltd. is presently undertaking a phased appraisal and development work program. The proposed appraisal program addresses the following key uncertainties for the Whicher Range Field:

  • Ability to enhance productivity using managed pressure drilling technology
  • Further reservoir characterization and understanding

The joint venture has commenced operations by contracting a rig and is re-entering the Whicher Range-4 well. Plans are to sidetrack the well using managed pressure drilling technology. 

The Whicher Range field was discovered in 1968 by Union Oil, and since then the field has had five wells drilled on the structure, each confirming significant columns of gas (approximately 2,133 feet or 650 meters). The most recent well, Whicher Range-5, was drilled in 2000. The reservoir has presented technical challenges to the previous operators and the current joint venture is seeking to determine if managed pressure drilling provides an enhancement to well productivity.

The initial Whicher Range 1 well flowed gas at 1.9 million cubic feet per day (MMcf/d) and the aggregate of all zones tested was 5.5 MMcf/d with low rates of water. Since this first discovery well, four further wells have been drilled, each confirming the presence of significant volumes of gas. Unfortunately, further attempts to stimulate the reservoir to increase productivity have encountered difficulties on each occasion.

GeoPetro Resources Company sold its interest in EP 408 and EP 381 to Whicher Range Energy Pty Limited for cash consideration and a Petroleum Sales Royalty Payment equal to 25 percent of the future annual earnings before interest, taxes, depreciation and amortization from the property interests up to a total amount of $2,200,000. Whicher Range Energy Pty Limited subsequently farmed out a portion of its interest acquired from us to CalEnergy Resources (Australia) Ltd. who is presently the operator of the EP 408 permit.


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