Tri-Valley Corp said that drilling has begun on the first of six new vertical wells to develop proved undeveloped (PUD) reserves at its Claflin oil project, located in the Edison Oil field near Bakersfield, California, US.

The company expects to complete the drilling of all six wells to an approximate depth of 1,000 feet within the next three weeks.

Following the completion, the new wells will receive their initial steam injection cycle and is expected to produce first oil by June.

An evaluation period of 60 to 90 days will follow to analyze results before commencing the second drilling phase at Claflin.

During 2010, the company reactivated four of eight existing wells at Claflin that had been drilled during the 1960’s in order to hold the lease by production.

Permitting for a 3-D seismic program of Claflin and the adjoining Brea lease, which Tri-Valley also holds, is underway with results from the seismic study anticipated by late May.

Tri-Valley has a 100% working interest and an 87.5% net revenue interest in Claflin.