Successful Implementation of Alternative Acid Stimulation in a Low Productive Reservoir in Abu Dhabi Offshore Field

Abstract

Abstract The aim of this paper is to share a successful case study of implementing the GLDA acid in two case study wells, which helped in improving the well performance where conventional HCl acid was not effective. Historically, the conventional HCl acid stimulation was performed on two case study wells, however, little to no improvement was observed after the acid job. The production history of both wells showed unstable behavior with load up tendency against the system pressure. Both wells frequently require unloading operation to put the well back online in case of any unforeseen platform shut down. In order to enhance the well performance and to sustain the productivity of the wells, an alternative acid called GLDA (Glutamic Diacetic Acid) stimulation was considered. GLDA is an environmentally friendly acid, biodegradable under water, non hazardous and can be handled and transported without special safety precautions. Unlike conventional HCl acid stimulation, GLDA acid is more expensive hence; a comprehensive process was adopted to ensure the proper candidate selection. For compatability study, the core samples from multiple reservoirs were tested with GLDA acid which showed positive results (creating deeper worm holes in all the cores provided), especially in the low permeable reservoirs. Fluid compatibility test of GLDA with crude oil was also found suitable without any asphaltenes precipitation & emulsion. Stimulation with GLDA acid was applied on both wells. Post job results proved significant enhancement in the production as well as production sustainability versus the conventional HCl acid stimulation.