Enhanced Oil Recovery
Enhanced oil recovery (EOR) is a process where reagents are directly delivered through an injection well in an effort to increase the efficiency of resource extraction in the oil industry. These injection techniques can increase the amount of crude oil that can be extracted from an oil field. Geophysical monitoring, when coupled with EOR methods, can provide cost efficient volumetric information on rock and fluid properties in subsurface reservoirs, helping to understand the fate of the reagents and their intended target. By repeating measurements over time, as time-lapse surveys, changes in geophysical parameters can inform about dynamic subsurface processes. This information allows enhanced oil recovery methods to be monitored, and to refine and optimize injection strategies.
Hydrogeophysics provides integrated geophysical surveys to the oil and gas industry covering a variety of subsurface characterization and monitoring methods for enhanced oil recovery.
As secondary and tertiary enhanced oil recovery methods are implemented, they are accompanied by changing properties within the subsurface reservoir. One significant change in the majority of recovery methods is in the conductivity of the reservoir. Geophysical methods are used to record and monitor these changes over time.
HGI’s Geotection™ technology has been used to monitor fluid flow in an oil reservoir during an EOR surfactant test at the Rocky Mountain Oil Field Testing Center (RMOTC). Geotection can use existing oil field infrastructure (injection and production wells), surface electrodes, and borehole electrodes, coupled with a dedicated 180-channel geophysical data acquisition system trailer, to provide near ‘real’ time monitoring. The state-of-the-art system was able to capture a complete snapshot of subsurface conditions (on average) every 20 minutes during the enhanced oil recovery operation. Measurements for the surfactant test at RMOTC were made using the existing steel-cased wells as electrodes with no additional infrastructure required. Test results confirmed the ability of Geotection to detect the movement, direction, and rate of fluid flow at reservoir depths. Such data are very useful for monitoring enhanced oil recovery and require minimal effort to adapt to virtually any oil field.
HGI’s geophysical methods and technologies, such as Geotection™, can be used as cost efficient reconnaissance tools for Enhanced Oil Recovery detecting movement, direction, and rate of fluid flow at reservoir depths.
Enhanced Oil Recovery Case Study
Rocky Mountain Oil Testing Center Injection
The figures below demonstrate geophysical monitoring methods used to track a solution injection at the Rocky Mountain Oil Testing Center. The image on the left shows a plan view of the electrical properties of a reservoir before an injection, and the image on the right shows the percentage change during the injection. An example electrical response from a monitoring well during a series of surfactant injections is shown below.