An Alert-Based Monitoring System to Evaluate a Water Injection Pilot in the Shushufindi Field, Ecuador

Abstract

Secondary recovery by water injection is one of the most popular methods to increase reservoir pressure and sweep efficiency in the industry. It is a cost effective technology in reservoirs such as Shushufindi field, where water, energy and sink points are easily available. This pilot aims to provide proof of concept of water injection in mature Ecuadorian fields. The water injection pilot project was carried out in the central north area of the field, in the lower U reservoir, selected as the target injection horizon due to pressure depletion. The injection started in December 2014 in SHS-246D and SHS-244D and then in 2015 two more injector wells were set up, SHS-247 & SHS-003. These wells are located in a 125 acres area, based on inverted five spot pattern. Secondary projects around the world have shown that the success of any water injection project is based on an exhaustive monitoring and surveillance process, along with using the many analysis tools and plots available. Shushufindi, however, needed a specific tailored toolset that fits the surface operating conditions, one that is able to monitor the variables required to understand the local reservoir hydraulic behavior, minimizes issues in the injection cycle, and provides quality data for the continuous improvement of the water injection pilot. In order to achieve this objective, some variables were selected and recorded in a group of theoretical plots. This was achieved by developing a series of workflows on a production management software platform, centered on an alert system to rapidly identify changes in the monitored injection variables and to respond if needed. This monitoring system allows a quick identification of well plugging issues in injector wells through the use of Hall plots, it also tracks the water quality at different points in the water processing plant allowing adjustments to made to the process to improve the water quality if needed, provides information for reservoir characterization monitoring, Voidage Replacement Ratio (VRR), and determines the water injection response in producer wells by monitoring the production parameters.

Metodología de evaluación técnica en campo para proyectos piloto de inyección de agua

“…De acuerdo al pozo productor SHS-053, influenciado por la implementación de los pilotos de inyección en el año 2014 en el campo Shushufindi, a los 11 meses del inicio de la inyección se observó un efecto combinado en el incremento de la presión de reservorio y el caudal de petróleo (Paredes et al, 2017).…”

“…Cuando se describe la salinidad influenciada por el agua de mar se refiere a la concentración de cloruros en el agua, puede expresarse en términos de concentración a conductividad eléctrica (Comisión Europea, 2021). En el análisis de estos proyectos piloto la salinidad debe tener una tendencia decreciente relacionada a la salinidad del agua inyección ya que se encuentran en rangos muy inferiores a la salinidad del agua de formación del reservorio U inferior, como el caso del pozo SHS-053 al año tres meses, la salinidad del agua tiene una tendencia decreciente siendo el indicador de la influencia del agua inyectada (Paredes et al, 2017).…”