Results of a Polymer Flooding Pilot in the Tambaredjo Heavy Oil Field, Suriname

Abstract

A polymer flood pilot has been ongoing since September 2008 in Suriname in the heavy oil Tambaredjo field operated by Staatsolie. Initially, the pilot consisted of one injection well and four producers and was later expanded to three injection wells and nine direct offset production wells (all vertical).The Tambaredjo oil field is the largest oil field in Suriname and has been producing since 1982. The field contains approximately 525 MMSTB STOOIP of 16°API oil with an initial viscosity of 300 -600 cP at reservoir conditions. Primary recovery (Ϯ 30% OOIP) is relatively high given the oil viscosity; this is believed to be due to a combination of compaction drive, edge water drive in the northern part of the field and limited bottom water influx in other areas, and perhaps foamy oil behavior. In spite of this high primary recovery, large quantities of oil remain in the reservoir, making it an attractive target for EOR.Due to the relatively thin pay, thermal methods have not been considered for the reservoir but on the other hand polymer flood was judged suitable. The oil viscosity is high but still lower than in other successful projects for instance in Canada while other reservoir characteristics are also suitable: low reservoir temperature and low water salinity allow the use of standard HPAM polymer, and high permeability is beneficial for injectivity. Moreover, the reservoir is highly heterogeneous, which has presented some challenges to the process.Initially, a polymer viscosity of 45 cP was injected which was later increased, first to 85 cP and then to 125 cP in order to improve the sweep efficiency. The overall response to polymer injection has been positive even if some wells have not responded positively to the injection, and incremental recovery (over primary) to date is estimated at on average 11% STOOIP. Due to the unconfined nature of the pattern some wells adjacent to the pilot have also shown response to injection.Given the success of the project, work is currently under way for an expansion of the polymer flood to encompass 33 additional injection wells.The paper presents the results of the pilot and describes the operations and challenges encountered during the project, in particular during the injection of the higher viscosity polymer. The combination of high reservoir heterogeneity, use of hydraulically fractured vertical wells and high polymer viscosity injected contribute to make this pilot an interesting field case.

Historical and recent observations in polymer floods: An update review

“…The injection strategy considered a variable injection rate (160-450 bbl/d) and an increase of polymer viscosity/concentration (45 cp @ 1,000 ppm; 85 cp @ 1,350 ppm and; 125 cP @ 2,300 ppm) over time. As of 2016, polymer had been injected in approximately 75% of the PV of the Tambaredjo pilot project reporting good oil response as recently reported by Delamaide et al (2016).…”

“…Generally, this type of reservoir shows an increase in productivity as a response of polymer injection being El Corcobo Field (Hryc et al, 2013), Pelican Lake / Brintnell project (Delamaide et al, 2014b), Tambaredjo Field (Delamaide et al, 2016) some good examples of this behavior. However, increases in oil rates observed during polymer injection can mask slight decrease in total fluid production, especially in horizontal producers such as in Medicine Hat Glauconitic C Pool (Batonyi et al, 2016) and Suffield Caen (Liu et al, 2012) polymer floods.…”

“…Tambaredjo field is a heavy (16°API and 300-1,100 cP) oil and relatively unconsolidated sandstone reservoir in Suriname (Delamaide et al, 2016; R., Mogollón, J. L., Bergwijn, S., Graanoogst, F., & Ramdajal, R., 2010; Manichand, R. N., Moe, K. P., Gil, L., Quillien, B., & Seright, R. S., 2013;Manichand and Seright, 2014;Moe, Manichand & Seright, 2012). Tambaredjo is described as a highly heterogeneous reservoir with a permeability contrast higher than 10:1 (T1 sand is a free crossflow reservoir).…”

Compaction and Dilation Effects on Polymer Flood Performance

“…Compaction played a major role during primary production of 20% OOIP from the Tambaredjo field in Suriname. In this field, a polymer flood pilot project was implemented, and an expansion of the polymer flood is under consideration (Moe Soe Let et al 2012, Manichand et al 2013, Manichand and Seright 2014, Delamaide et al 2016. During simulations, a compressibility of 5.6×10 -4 psi -1 was used to match reservoir behavior for this field.…”

“…During simulations, a compressibility of 5.6×10 -4 psi -1 was used to match reservoir behavior for this field. Individual production-well responses to the polymer flood varied greatly throughout the pilot project (Moe Soe Let et al 2012, Delamaide et al 2016. Most likely, reservoir heterogeneity was dominantly responsible for this variation.…”