Leon, J. M. (Ecopetrol SA) | Castillo, A. F. (Ecopetrol SA) | Perez, R. (Ecopetrol SA) | Jimenez, J. A. (Ecopetrol SA) | Izadi, M. (Ecopetrol SA) | Mendez, A. (Ecopetrol SA) | Castillo, O. P. (Ecopetrol SA) | Londoño, F. W. (Ecopetrol SA) | Zapata, J. F. (Ecopetrol SA) | Chaparro, C. H. (Ecopetrol SA)
Palogrande-Cebu is a mature clastic field located in the south of Colombia and part of the production train of the Monserrate Formation that has several fields and presents an OOIP about 1000 MMBBLs. In these fields Ecopetrol have been tested different chemical EOR/IOR technologies like polymer flooding, CDG and conformance treatments with encouraging results. Palogrande field has been in production since 1971, and under peripheral water injection since 1984, with a recovery factor of 28%. The reservoir has a permeability between 6 and 150 mD, and a crude with an in-situ viscosity of 9.4 cP at reservoir conditions. As part of a portfolio screening within Ecopetrol, chemical EOR was considered the most viable option for the field. This lead to a polymer flood pilot in Palogrande-Cebu in two patterns from May 2015 to June 2017.
The present paper presents the results of the pilot, which includes the assessment of two different sources of water to prepare the polymeric solution, fresh water and produced water. Likewise, three different polymers were used to assess the impact on injectivity of the molecular weight considering the low permeability of the reservoir. Moreover, the paper presents the data from a comprehensive surveillance and monitoring program, which includes a polymer backflow test to assess the polymer viscosity in the reservoir.
As of June 2017 the accumulated polymer injection was 2.07 million barrels distributed between both injectors, and a projected incremental recovery factor of 8% in the most mature pattern, and 2% in the less mature pattern, with water cut reductions up to 14% in some wells. Based on the success of the pilot, the feasibility of expanding the polymer flood is currently being considered to further develop the field.
The Green River, Utah holds the world's greatest oil shale resources. However, the hydrocarbon, which is namely kerogen, extraction from shales is limited due to environmental and technical challenges. In this study, we investigated the effectiveness of the combustion process for shale oil extraction. Samples collected from the Green River formation were first characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Then, series of dry combustion tests were conducted at different heating rates and wet combustion tests by water addition. The combustion efficiency was enhanced by mixing oil shale samples with an iron based catalyst. The effectiveness of dry, wet, and catalyst added combustion processes was examined by the thermal decomposition temperature of kerogen. Because the conventional oil shale extraction methods are pyrolysis (retorting) and steaming, the same experiments were conducted also under nitrogen injection to mimic retorting. It has been observed that the combustion process is a more efficient method for the extraction of kerogen from oil shale than the conventional techniques. The addition of water and catalyst to combustion has been found to lower the required temperature for kerogen decomposition for lower heating rate. This study provides insight for the optimization of the thermal methods for the kerogen extraction.