Abstract

This paper highlights the successful experience of Mobil Oil Indonesia Inc. (MOI) in using a special organic acid system to stimulate high pressure and high temperature Arun wells.

MOI originally used hydrochloric acid to stimulate Arun wells. This type of acid is very effective in removing wellbore damage due to the invasion of drilling and workover fluids. However, corrosion of the tubing string caused by this acid has complelled MOI to stop using it and to find a better alternative.

The organic acid formulation, which is currently being used for Arun well stimulation, consists of 13% acetic and 9% formic acid. This acid, theoretically, has the dissolving power for carbonate equal to that of 15% hydrochloric acid.

Field data from ten wells have indicated that the productivity of newly completed or worked over wells increased by an average of 100% following an organic acid stimulation. This successful organic acid stimulation result has encouraged MOI to expand its application to the selective stimulating of lower pay zone intervals in both new and old wells. The bottom zone of the Arun Reservoir is thought to be where condensate rich gas lies. By stimulating this condensate rich zone, MOI expects to be able to maximize its condensate production.