Polymer-Injection Pilot in Colombian Field Indicates Reduced Carbon Footprint
Authors: Carpenter Chris 
Published: November 2024

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 218169, “Carbon Footprint and Energy Intensity Assessment for Enhanced Oil Recovery (EOR) Based on Polymer Injection: A Colombian Case Study,” by Henderson I. Quintero, SPE, Pedro L. Solorzano, SPE, and Carolina Barbosa, Ecopetrol, et al. The paper has not been peer reviewed.

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Chichimene is an oil field in eastern Colombia. Since 2014, enhanced oil recovery (EOR) using a water-injection process has been performed successfully in part of this field. A polymer-injection pilot was executed over five injection patterns to optimize this process as a promising strategy for polymer-based EOR in challenging reservoir conditions with high temperatures and heavy oil.

Field Background
Included in Colombia’s energy-transition strategy are EOR technologies that, through the acceleration of oil production even with low energy consumption, increase the efficiency and carbon intensity of conventional oil-production processes. Several studies in the literature have reported improved energy and carbon indicators as a result of implementing EOR using thermal and chemical methods. Among these, polymer injection promises higher incremental oil production with lower energy consumption.
The polymer-flooding (PF) pilot in the Chichimene field was performed to evaluate this technology’s ability to displace the heavy crude oil of the Fm1 formation (350–700 cp). The reservoir is more than 20 km long by 6 km wide and features 250–300 ft of thickness, with permeability between 100 md and 10 D and a depth of approximately 6,200 ft true vertical depth subsea.
Polymer injection began at the end of 2015 in an extensive pattern (N1), followed by a smaller pattern (N2) in 2018 after a short water-injection stage. The polymer injection in medium patterns (N3 and N4) and a second small pattern (N5) began in 2019, being considered early chemical EOR because they were performed after the primary production stage. The well spacing of the patterns is 10 and 40 acres, respectively. The producer wells of each pattern are displayed in Table 1 of the complete paper.
The PF project injected 21.65 thousand STB of polymer solution. At the end of 2022, incremental oil production was 4.9 billion bbl. At the time of writing, patterns show incremental recovery factors of between 4 and 9%. The reservoir showed strong signals of repressurization, gas/oil ratio reduction, water/oil ratio control, and oil incremental recovery.
Energy consumption and carbon intensity were calculated for the oil production baseline case [waterflooding (WF) or primary production] and PF, considering the field’s energy matrix. The results were compared to quantify the effect of PF on these efficiency indicators.

Evaluation of Product System
Energy consumption was calculated for each phase involved in the processing system: lifting fluids, oil dehydration, water-clarification treatment, water reinjection, and PF. The evaluation did not include solvent or facilities to dilute the crude oil or the pumping energy used to deliver the oil to the pipeline system. Currently, the total volume of water produced is reinjected into the reservoir for pressure maintenance and oil-recovery purposes. Also, part of the produced gas is used in heaters and fire tubes for dehydration, but most is burned in a gas flare.