The company said cores taken from the upper Maingit section at a depth of 884 metres exhibited excellent porosity and permeability, despite reservoir quality being a concern in the Visayan Basin. The core also contained fluorescence and some hydrocarbons.

But a second test through perforated casing at a deeper depth of 1897-1903 metres did not move hydrocarbons to the surface.

Mechanical failure also stopped the company from testing a section at a depth 838m, the company said.

Meanwhile, the section that returned positive hydrocarbon readings has been isolated with plugs for testing at a later date.

“A 30-foot (9.1m) interval which coincides with the core will be perforated, tubing hung and the well suspended in preparation for a later test of this section,” Gas2Grid managing director Gundi Royle said.

“The appropriate equipment (wireline) for this test is not on the site, but will be sourced in the near future.”

The drilling rig has now left the site.

Looking ahead, Gas2Grid intends to conduct further analysis of data from the well, including sophisticated electron microscope analysis of rock samples, further core analysis and fluid analysis, the company said.

It will also undertake reservoir geometry and fracture system modelling to predict the distribution of fluids.

In addition, Gas2Grid will develop further appraisal locations on the Malolos and Zaragosa prospects.

“The licence contains 10 other leads, which need to be developed into prospects,” Royle said.

“Zaragosa, which had blown out, is an obvious target, but the Balungog carbonate play will also be developed with a view to introduce variation into the portfolio.”

Gas2Grid, which holds a 100% interest in the 100,000 hectare licence, announced in August it was appraising the Malolos feature to establish a sustainable gas flow.

SC44 contains two 1960s gas discoveries, Malolos-1 and Zaragosa-1. In 1960 Malolos-1 flowed gas from drill stem tests at rates of 5 million cubic feet per day and 12.6 million cubic feet per day from zones at 850m and 1850m respectively.

The company re-entered this well on December 10.

The Malolos feature, with potential gas resources of 50 bcf, is on trend with three other culminations - Butak, Barili and Esperanza - which have estimated gas resources of 240 bcf, based on assumptions from the Malolos-1 well, according to Gas2Grid.