Weyburn Oilfield Core Assessment Investigating Cores From Pre and Post CO₂ Injection; Determining the Impact of CO₂ on the Reservoir

Abstract

The Weyburn and Midale oilfields in Saskatchewan, Canada contain the largest amount of injected anthropogenic CO₂ on the planet. Since 2000 there has been 25 million tonnes of CO₂ stored in these reservoirs, and an additional 3 million tonnes stored annually. The Petroleum Technology Research Centre (PTRC) is running a project on the Weyburn oil field to study CO₂ movement and detail the effects of its injection. This work will build upon the rich datasets from the Weyburn and Midale fields to better inform prospective CO₂-EOR operators, government regulators and service providers on how to improve the efficiency of CO₂-EOR operations, maintain the safety and integrity of CO₂ storage, and limit liabilities and risks during operations. This project is investigating the effect of injected CO₂ on rock framework and the pore space in the Weyburn Midale reservoir. Two pressure observation wells with extensive cores have recently been drilled in the Weyburn field. This provides a unique situation to observe the influence of 15 years of injected CO₂ on the mineralogy and rock properties of the reservoir. Comparing the recently drilled wells to wells that were drilled prior to CO₂ injection will reveal effects of injected CO₂ on the reservoir matrix. This field scale “laboratory” provides a rare opportunity to investigate the results of injected CO₂ on the reservoir at an active injection site leading to a better understanding of the reservoir to injected CO₂. These findings could increase CO₂ sweep efficiency and storage capacity The analytical techniques that are being utilized to determine if the injected CO₂ has impacted the reservoir include QEMSCAN to determine the mineralogy and porosity, XRD/XRF, SEM images, and cathodoluminescent analysis.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016