Development and Implementation of a Multifunctional Viscosity-Reducing System in Extra-Heavy Oil Producing Sandstone Reservoirs– Historic Case

Abstract Development and implement a multifunctional viscosity-reducing chemical system for sand fields with extra-heavy oil producing wells to improve the rheological properties and fluid mobility in the critical matrix, achieving increasing of the current recovery factor of the oilfield, improving efficiency of the artificial lifting production system's pump and the handling of hydrocarbons from the reservoir through well and to the surface; validating its functionality and performance with the support of laboratory tests. The methodology includes fluid-fluid interaction tests such as gas chromatography, rheology studies, SARA composition analysis and physicochemical characterization of oil samples. Also, the compatibility with the viscosity reducing system is evaluated, and concepts such as reservoir pore volume calculation, simulation of fluid distribution according to petrophysical properties and the result in the reduction of indirect costs associated with the Artificial lift System (ALS) equipment are applied. The chemical system pumping was performed on August 13, 2024, in a production oilwell, it was eleven (11) hour shut-in was carried out for giving the chemical system residence time and contact with the formation fluids (reservoir oil). During the job, treatment pumping lines were connected to the well's production casing and the displacement was performed with water. This action avoids dismantling the rod pumping unit installed in the tubing to bring back the pumped products to the surface after the treatment, also safety issues in the valve half-tree are a plus. Since the chemical system pumping job on August 13, 2024, a continuous production of oil is observed in a range from 100 bpd to a maximum of 130 bpd, declining until 15 bpd before its closure on October 30, 2024, evidencing a continuous flow from the well to the production facility (Flow station). During this period, the ALS was optimized, and surface sampling was taken to determine the physicochemical analysis of the oil, SARA analysis and viscosity determination through time. A 94% reduction in viscosity was obtained from 98,130 (cp) to 4,733 (cp) @ 30 °C, a 2.3-fold increase in production (from 40 to 134 bpd), and an improvement in the operational efficiency of the Rod Pumping System (volumetric, downhole pump displacement and maximum load reduction). The information presented lays the foundation for a novel and robust methodology for treating extra-heavy oil wells in sand fields with super high viscosity problems, supported by a set of laboratory tests necessary for understanding the chemical composition of the oil, optimizing the reserves recovery & downtime of the installed Rod Pumping unit.