Preliminary Assessment of Tambaredjo Heavy Oilfield Polymer Flooding Pilot Test

Abstract

Abstract The literature screening criteria for polymer flooding established the maximum oil viscosity at 150 cP; however, oil price increases and technology improvements have encouraged pilot tests in heavy oilfields. This paper shows the results of an ongoing polymer flooding pilot test in an inverted 5-spot well pattern in an onshore field in Suriname. The reservoir is fluvial deltaic with 900 ft depth in the pilot area. The oil viscosity is 400 cP at 97°F. The objective of the pilot test is to demonstrate that the production rate and recovery factor can be increased economically to extend the productive life and profits of the oilfield. Polymer flooding began after laboratory, numerical simulation, and preliminary economical evaluations indicated its feasibility. The analysis of reservoir-related parameters showed that uncertainties in long-term injectivity, polymer stability, wells communication, and fluid fingering-channeling cause a high-risk index. Therefore, a detailed subsurface surveillance and monitoring program was prepared and implemented. This program was guided by way forward road maps that target injection, flooding performance, and production assessment, and are based on a "plan, do, check, and act" approach. To date, 0.22 pore volume (PV) of the well pattern has been injected. The bottomhole pressure (BHP) of the four producer wells has increased by 1.7 to 2.7 times, showing the communication with the injector well, hence, after production has been adjusted to maintain the BHP between 75 to 100 psi. The injectivity is greater than the value estimated for profitability. Polymer breakthrough occurred in two of the 5-spot wells after approximately one year of injection, as forecasted in the reservoir simulation. A slight increase in the pattern oil production and water-cut reduction has been observed. Therefore, incremental oil production is expected in the forthcoming months.