Techbits: Waterflood-Management Strategies Explored in Argentina (February 2010)
Authors: JPT staff _ 
Published: February 2015

Techbits
An SPE Applied Technology Workshop (ATW) titled “Keys to Effective Mature Waterflood Management” held in Buenos Aires allowed more than 100 industry professionals to share best practices and lessons learned in waterflood management.
Waterflood Case Studies
The ATW’s opening session highlighted several case studies in Argentina’s fields. Daniel Biedma and Enrique Muruaga of Tecpetrol reviewed different waterflooding techniques aimed at improving the oil recovery factor by maximizing the volumetric sweep efficiency in the mature El Tordillo field. The techniques included infill drilling, selective-water-injection completions (multiple packers and mandrels), modifying water-injection patterns, and a gel-injection pilot test that was expanded to 14 injection patterns.
Alejo Holub and Federico Schamann of Chevron presented a holistic field-performance optimization of the mature El Trapial oil field. They showed how an integrated approach incorporating stochastic models and multidisciplinary teams can result in better decisions. This approach, which also uses Monte Carlo simulation, reservoir simulation, and decision-tree analysis, is especially useful to evaluate and select best scenarios from multiple possibilities during field development and latter stages of maturity.
An Apache presentation on a waterflooding project in the Guanaco Centro field, which was discontinued due to operational problems, showed how the project could be revitalized and recovery factors improved by redesigning waterflooding patterns. Engineers performed a single-layer numerical simulation study to evaluate pattern reconfiguration to optimize the recovery factor of the field and keep costs down.
Reservoir Characterization and Modeling
William Cobb, 2008 SPE president and principal of William Cobb and Associates, presented a method to determine waterflood volumetric sweep efficiency by using oil-production rates. He described how production history and pressure/volume/temperature properties can be used to estimate volumetric sweep efficiency within certain regions of a field. Identifying regions of low volumetric sweep efficiency may show potential areas to improve the recovery factor through different techniques, such as infill drilling, selective completions, or gel injection.
Marcelo Crotti of Inlab presented a study highlighting the importance of considering capillary forces as well as viscous and gravity forces in models that simulate the movement of waterfronts in a reservoir. Laboratory experiments indicate that under certain conditions, the influence of capillary forces can cause water to move faster through low-permeability layers. Crotti also discussed the importance of reservoir heterogeneities and how they can affect the response of the waterfront.
Improved-Oil-Recovery Techniques
An ongoing alkali surfactant polymer pilot test for a field in Neuquén Basin was next reviewed by Pluspetrol’s Raul Puliti. Laboratory testing, including core analysis and the Helle Shaw cell test, was being carried out to select chemical product candidates. The patterns for the pilot test were selected, and Puliti stressed that before commencing the pilot test, it was important to ensure production and injection remain stable for the pattern and neighbor wells.