Primeline Energy has said that positive electric logging results have prompted the company to prepare for drill stem testing (DST) of potential reservoir zones in the LS 35-3-1 exploration well in block 25/34 East China Sea.

Primeline has completed two runs of electric logging comprising gamma ray, sonic, spontaneous potential, resistivity and neutron-density logs over the interval from 1,383mt to total depth.

According to the company, interpretation of the log data leads to the preliminary conclusions including: good thick sandstone sequence with no indications of hydrocarbons in Target Zone 1; sandstone sequence with limited indications of hydrocarbons in Target Zone 2; and in Target Zone 3, gross 60mt section of sandstone and mudstone interbeds with over 20mt aggregate of potential hydrocarbon pay in two zones.

The initial interpretation indicates presence of gas in these zones. There is no indication of a gas water contact on the logs. Based on these results, Primeline has instructed China Oilfield Service (COSL) to mobilize DST equipment to the rig and prepare for testing.

Primeline is currently conducting a formation evaluation logging program including vertical seismic profiling, reservoir characterization instrument and side wall coring, before setting the 9 5/8 inch casing.

The DST program will commence in about 7-8 days after the casing program. If two zones are tested it is anticipated that it will take approximately two weeks. Primeline has agreed terms and will contract COSL for the DST on a per zone turnkey basis.

This exploration drilling operation is part of the step-out drilling campaign that Primeline is implementing as part of its rolling exploration and development strategy. Primeline and CNOOC are preparing for the development of Lishui 36-1 gas field following signing of development agreements with CNOOC in March.

The LS 35-3-1 well location is approximately 15km south west from the Lishui 36-1 gas field and is one of the several prospects identified by high quality 3D seismic data in the vicinity of the Lishui 36-1 gas field.