Identifying and Unlocking Hydrocarbon Potential in Cretaceous Sandstones With High-Density Calcareous Concretions in Rondon-Terecay Area, Arauca, Colombia

Abstract This paper endeavors to present the potential and development strategy for the K2C reservoir, characterized by low-resistivity sandstones interbedded with high-resistivity calcareous concretions. These features represent a reservoir characterization challenge due to the lack of logs response and the difficulty to quantify the oil volume storage by the sandstones in the calcareous zones. The study employed a comprehensive sedimentological analysis to delineate the geometry and architecture of the K2C reservoir in the Rondon area, integrating various data sources such as cores, logs, cuttings, and petrography. The selection of wells for workovers, based on integrated data, yielded favorable results, affirming the reservoir concept and prompting expansion in Rondon- Terecay and other Llano’s areas. The 2023/2024 workover campaign in Rondon yielded an average production of 1100 barrels of oil per day (BOPD) with an 80% water cut, validating the natural productivity of the reservoir without chemical or mechanical treatments. This success unveiled substantial reserves increase of 56%, for future development, with projected production peaks of 2000 BOPD by the end of 2024 and 2400 BOPD in 2026. The study also underscores untapped opportunities in northern fields, notably in Cravo Norte, indicating significant additional hydrocarbon potential. By validating the reservoir concept in calcareous sandstones with high-density calcareous concretions in Rondon- Terecay, this paper offers a novel perspective, providing valuable insights for practicing geologist and engineers to identify and develop analogous reservoirs, thereby enhancing their management and understanding of hydrocarbon assets.