It is generally thought that EOR technology costs much, so the budget for EOR in low oil price period is inhibited. For further recogonize the issue, the paper conducted a follow-up technical and economic evaluation for a EOR project of high water cut mature oil field.

LHSC is a multiple layer high pour point reservoir with severe uneven sweeping problem. The water cut is up to 95.3%. The new polymerflooding (NPF) application area is composed of 10 injection wells and 21 production wells. The injection anount was designed as 0.3 PV, and it was composed of the main slug of a novel paticle type polymer SMG and the pre slug of volume swellable particle PPG carried by polymer weak gel. During the injection process, the slug parameteres such as SMG diameter were adjusted. The numerical simulation model and economic analysis model were built up. The technical and economical competency of the project evaluated under different oil price.

From December 21, 2010 to December 31, 2016, the total EOR slug injection amount was 0.29 PV. Among the 21 producers, 19 producers obtained good effect of oil rate increase and water cut decrease. The daily oil rate was increased from 27.0 t to 58.5 t for the highest, and the water cut was decreased from 95.3% to 91.1%. The cumulative oil incremental was 3.2×104t. Numerical simulation results showed that by the end of the project, the cumulative oil incremental would be 4.35×104t, and the recovery incremental would be 4.9%. Based on the actual oil selling price of each year, the input to output ratio was calculated as 1:3.1, and the EOR cost of one barrel oil produced was 21.5 USD, while the cost of one barrel oil produced in waterflooding is 52.1 USD. Under 30 USD/bbl oil price, the input to output ratio is 1:1.4. The results show that the NPF project has good technical and economic effect, and even under extreme low oil price, it still has economic feasibility.

For the developed mature oil fields, the geological and development recognition is certain, and there are complete facility contruction. Under low oil price condition, it is obviously more economical to use novel efficient EOR technologies.The opinion of the paper may provide some reference for oil companies to make investment decision in low oil price period.

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