Practical Enhanced Oil and Gas Recovery (EOR/EGR) for Unconventional Wells and Reservoirs - a Next Generation Huff-and-Puff Treatment Combining Gas with Nanoparticles

Unconventional reservoirs unlocked through the combination of horizontal drilling and fracturing have revolutionized the exploration and production of hydrocarbons. In 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 relative infancy. Next generation challenges for economic production, as well as generating free cash flow, include the need for improved hydrocarbon recovery. Current initial drilling and completion practices (aka primary recovery) claim in the range of 6-10% of the oil and up to 25% of the gas in place. Significant opportunities exist to improve upon secondary and tertiary recovery practices for unconventional reservoirs. One of the more recent methods of enhanced hydrocarbon recovery on existing unconventional wells includes utilizing 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, have demonstrated a synergistic treatment that provides an improved incremental production of hydrocarbons over an extended period. Relative costs of these new nano/gas treatments are significantly less than traditional methods (i.e., refracturing), providing a greater economic return for operators looking to enhance recovery from their existing wells. Most importantly, this new nano/gas EOR/EGR method demonstrates the lowest capex, unit cost of production (BOE/Mcfe) and practical scalability needed for full field re-development to maximize recovery out of existing unconventional wells.