Implementing a Novel Organic Acid Matrix Stimulation to Successfully Remove Formation Damage: Case Studies, Iraq and Ecuador Oilfields

Abstract

This paper discusses the efficiency of design, application, and pumping schedule of organic acid treatments used for mature fields in Iraq. Due to challenging completion schematics, an enhanced fluid placement method consisting of coiled tubing (CT), nitrogen, and a fluidic oscillator tool (or combination) is presented. By the time a well completion is achieved, oil production for most wells begins to decrease because of formation damage caused by fines migration, clay swelling, scale deposition, emulsions, organic deposits, or previous unsuccessful hydrochloric acid (HCl) or HCl/hydrofluoric acid (HF) stimulation treatments. A matrix stimulation/acidization using a tool that enables pumping the treatment, either as near as possible to or reciprocating across the perforations, is necessary to help remove formation damage, enhance recovery, and increase oil production (producer wells) or water injection (injector wells). Matrix stimulation treatments were performed for both producer and injector wells for an Iraq field, demonstrating enhanced conductivity results and increasing oil production up to 2000 BOPD over the last production rate or improving the water injectivity rate by 10000 BWPD. In addition, for those wells in which an electrical submersible pump (ESP) was installed, it was necessary that the selected stimulation fluids did not adversely affect the internal components of the ESP. To reach this goal, analysis of the following parameters was performed: mineralogy, regain permeability test, temperature, fluids properties, rock properties, and formation damage. Based on the analysis, customized designs assisted by software simulations were developed to determine the most effective treatment selection. Novel/Additive Information (25-75 words suggested) This paper describes how well information and correct analysis, and design can help to develop a customized optimal intervention strategy, identify the best solution to remove the formation damage, and deliver value added to the operators.