Information relative to the preparation of two polymer flood pilots in the West Central Saertu area of the giant Daqing oil field in China is presented.

The reservoir features of the West Central area of the field contribute to suggest polymer injection as an attractive process. Numerical simulations as well as economical calculations based on anticipated optimum operational conditions have confirmed this interest.

The primary scope of the reported laboratory study is the use of a new methodology for selecting the most appropriate polymer chemical structure. Three main selection criteria, namely maximum intrinsic viscosity, minimum adsorption and absence of attractive polymer-polymer interactions were considered and a Polyacrylamide containing 20% of acrylate group was chosen. This polymer was found to show high effective viscosity and low retention in core flows. A xanthan sample also suitable according to these technical criteria was not considered due to economical reasons.

The two pilot tests are being designed on these bases. The first one aims at checking the ability of polymers to reduce vertical channeling within a single layer. The second will evaluate the improvement of vertical sweep efficiency when two separate layers open in wells with single completions are subjected simultaneously to polymer injection. The well layout of each pilot and the type of information expected from the observation wells are described.

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