Abstract

Chemical flooding presents an effective technique for enhancing hydrocarbon production from sandstone and carbonate reservoirs. Several chemicals are injected to interact with the reservoir system and increase oil production. However, the impact of these chemicals on reservoir integrity is very important. Therefore, this paper investigates the impact of two effective chemicals on formation integrity. The influence of injecting thermochemical fluids and chelating agents on the reservoir properties is examined.

In this work, several experiments were carried out including coreflooding, nuclear magnetic resonance (NMR), and permeability measurements. Coreflooding experiments were conducted using reservoir conditions. NMR and permeability measurements were conducted before and after the flooding experiments to determine the impact of chemical injection on the rock permeability and porosity system. In addition, ions concentration measurement was conducted using ICP (inductively coupled plasma) analysis.

The obtained results showed that significant improvements in the rock permeability was induced by the injected chemicals. Chelating agent fluids dissolve a portion of the formation matrix, lead to creating channels/wormholes at high chemical concentration. While thermochemical fluids induce a new porosity system due to the in situ generation of pressure and heat inside the treated rocks. ICP analysis indicates a significant increase in calcium concentrations.

This paper presents the impact of chelating agents and thermochemical flooding on rock integrity. The changes in rock properties due to chemical injection are evaluated. Overall this study will help in designing and conducting chemical treatment for hydrocarbon reservoirs, which can lead to maximizing the oil recovery without considerable impact on the reservoir integrity.

Introduction

Chemical flooding is one of the most effective techniques that are used to increase hydrocarbon production (Brandas, 2012). Different types of chemicals are used to improve the oil recovery from carbonate and sandstone reservoirs. Understanding the changes in rock properties during the chemical treatments can help in optimizing the operational efficiency and reduce the cost. Also, it can help in minimizing the impacts of chemical treatments on reservoir integrity. Recently, chelating agents' fluids have been proposed as effective chemicals that can stimulate the reservoirs within minimum impacts on the well completion (Fredd and Fogler 1996 and 1997). Chelating agents can be used in different operations such as drilling, completion, and well stimulation. These fluids can dissolve a portion of the rock surface and generate new wormholes, facilitating the hydrocarbons flow toward the wellbore (Hoefner and Fogler, 1987, Hassan et al., 2020).

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