Proving the Mahanagdong B Resource: A Case of a Large Scale Well Stimulation Strategy, Leyte Geothermal Power Project, Philippines

Abstract

The Mahanagdong-B production sector of the Leyte Geothermal Power Project was faced with a serious steam supply problem in the first half of 1997, with only 14 MWe available at the wellhead of seven production wells for a 60 MWe power plant.

SignrJcant thermal degradation of the resource block brought about by extensive drilling prevented the discharge of most wells even with the aid of air compression and nitrogen gas Irting. Detailed analysis of reservoir and drilling data also revealed that all the wells had been mud-damaged.

The problem was compounded by the contractual obligation of PNOC-EDC to produce 60 MWe equivalent of steam to the power plant by the middle of the year.

A comprehensive well stimulation strategy was laid out through which the situation was put to a manageable level by June 1997. The strategy involved the simultaneous use of two coiled tubing units, one rig and two acidizing equipment spreads all in one pad, to stimulate, discharge and commission the seven production wells in less than three months.