Tailored Metal Oxide Nanoparticles-Based Fluids in Acid Restimulation Treatments Reverses Long-Term Hydrocarbon Decline: A Pilot Study in Wolfcamp (A) Formation

Abstract

Abstract Multi-fracture horizontal wells suffer from high hydrocarbon decline and water-cuts after initial flow back. This behavior is in part because of near/far field-fracture conductivity damage. Re-fracturing operations (acid or proppant) can mitigate these problems yielding a good cleanout performance and stable oil recovery trends. This paper details a successful pilot to improve long-term well performance using acid stimulation aided by a pioneering tailored metal oxide (TMO) nanoparticles-based fluid in Wolfcamp (A) formation. Seven wells (in two different areas) with similar designs, same geological landing zone, located within 1 mile from each other were selected to be re-stimulated with different surfactant blends. These wells were producing an average of 4,500 bwpd at a 96% water cut. Acid stimulation programs with a total treatment volume of about 2,000 barrels was designed to stimulate each well. Regular surfactant was added to the treatment fluid in 5 wells, while 2 wells implemented the TMO Nanofluid. The TMO Nanofluid had previously been shown to improve production rates and reduce water cuts with specific focus on long-term performance. Water cuts, gas-oil ratios (GOR), and hydrocarbon decline rates were monitored daily to observe any significant differences between the well production behaviors. The surfactant-injected wells demonstrated an average of 40% production decline in the 1st six months. The TMO Nanofluid-injected wells showed a reverse trend with a production decline of 5% in the 1st month followed by a production improvement of 10% in the 2nd month and less than 10% production decline after 6 months. This type of behavior is consistent with previous field experiences with the TMO Nanofluid where the production improvement had been sustained over time. The water cut in all wells decreased to about 96%. The TMO Nanofluid worked by providing a unique long-term wettability alteration, reducing the interfacial tension, allowing the chemicals to be retained in the fracture/reservoir phase. It also functions to remove near-wellbore organic formation damage via the structural disjoining mechanism. Overall, this results in better stimulated wells for long-term performance. The unique characteristics of the TMO Nanofluid in acid stimulation treatments can help restore well/reservoir conductivity and remove near-wellbore formation damage, resulting in improved long-term performance characteristics and improved production decline rates.