A Successful Polymer Flood Pilot at Palogrande-Cebu, A Low Permeability Reservoir in the Upper Magdalena Valley, Colombia

Abstract

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.

Investigation of Polymer-Assisted CO2 Flooding to Enhance Oil Recovery in Low-Permeability Reservoirs

“…The polymers can maintain a viscosity of 2-3 cP (2500-4000 mg/L), with good injection and enhanced oil recovery effects. Leon et al [27] reported a successful field pilot of the polymer in the low-permeability Palogrande-Cehu field. Considering the low permeability of the reservoir (6-150 mD), three polymers with different molecular weights (average concentration 1021 mg/L, viscosity 3.43 cP) were used, and the viscosity change was monitored.…”

Study on Micro-Displacement Mechanism and Reservoir Compatibility of Soft Dispersed Microgel

“…Polymer is developed from inorganic profile control agents such as clay, fly ash, and cement to organic gel profile control agents in the 1970s. Although polymer flooding has made great progress [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ], due to its small injection volume and small treatment radius, it can only play a certain role in the longitudinal heterogeneity near-well zone, and it is only a production measure, strictly speaking. In order to solve the limitation that polymer flooding can only be used in the near-well area.…”

Experimental Investigation on a Novel Particle Polymer for Enhanced Oil Recovery in High Temperature and High Salinity Reservoirs

“…Conventional and mature EOR technologies based primarily on polymer (HPAM) include polymer flooding, surfactantpolymer flooding (SP), alkaline-surfactant-polymer flooding (ASP), and crosslinked polymer gel flooding. ese technologies have achieved significant success worldwide [1][2][3][4][5][6][7][8][9]. However, the temperature and salinity resistance of the polymer is limited, and as a continuous phase high viscosity fluid, its mechanism of oil displacement is also contradictory [10][11][12][13][14][15][16][17].…”