Acid Stimulation of Injection Wells in the Leyte Geothermal Power Project, Philippines

Abstract

Acid stimulation was applied in injection wells MG-7RD, 4R7D and 4R12D in the Leyte Geothermal Power Project, Philippines, to increase their injection capacities affected by mud during drilling. Several improvements were initiated in term of well testing and analysis and acid treatment design to increase the effectiveness of the stimulation compared to previous acid stimulation jobs.

The use of electronic pressure-temperature-spinner logs and improved well test interpretation became essential for better candidate selection, acid treatment design, and quantification of pre-acidizing well parameters and evaluation of acidizing results. Further improvements in acid treatment design were also achieved with the refinements in spotting the acid, increased injection rates and the use of chemical diverters. Post-treatment results showed a 77% to 357% increase in injection capacities.