(475c) Improved Oil Recovery (IOR) Method for Unconventional Reservoirs with a Next Generation Huff-and-Puff Treatment Combining Gas with Nanoparticles for Enhancing Recovery

Unconventional reservoirs unlocked through the combination of horizontal drilling and fracturing have revolutionized the exploration and production of hydrocarbons across the globe. For the United States, this success has opened the way to exporting of these hydrocarbons along with a new renaissance in the petrochemical processing industry due to the supply of inexpensive energy and feedstocks. The Unconventional Revolution, now some 10+ years in the making is still in its infancy. Next generation challenges for economic production include the need for improved hydrocarbon recovery. Current initial drilling and completion practices (aka primary recovery) only claim ~5-10% recovery of the oil in place. There is significant opportunity to improve upon secondary and tertiary recovery practices for unconventional reservoirs. One of the more recent methods of improved oil recovery (IOR) used on existing unconventional wells includes combining two injectants, gases and nanoparticles in a huff-and-puff (HNP) style treatment. Gases such as carbon dioxide (CO₂) and nitrogen (N₂) have a long history of use for improving recovery. Nanoparticles, a more recent innovation for recovery enhancement, have demonstrated that ability in fracturing formulations. An even more recent practice, combining the two in a traditional HNP-style injection in existing wells, creates a synergistic treatment that provides an improved incremental production of hydrocarbons over an extended period. Thus, providing a greater economic return for operators looking to enhance recovery from their existing wells.

In our initial case study, we treated a total of five open-hole horizontal wells, in the Austin Chalk and Buda Limestone, with a combination of (N₂) and nanoparticles. We monitored production for 180 days post treatment and reported on well response, showing incremental production improvements ranging from 12% to 564%. With the key learnings from those first wells, we designed a treatment for the next well – a horizontal well in the EagleFord shale treated with nanoparticles and CO₂, targeting production improvements that provide the operator payback within a 60 to 90 day period and lasting longer than six months. This paper reports on the gas and nanoparticle HNP treatment response of that EagleFord well’s designed treatment along with updating the continued production response of the initial five wells treated. What we have seen with the results to date, is that we can tune the right treatment combination, targeting a desired production response and economic returns for the operator.