Polymer Injectivity Design Tanjung Field Zone-C- Indonesia

Abstract

Understanding the polymer behavior in porous media is a critical step to achieve successful operation of polymer flooding. Shear-thinning, shear-thickening and Newtonian behavior of polymer solution will affect its ability to enter the porous media, which is commonly known as injectivity characteristic. Therefore, injectivity test is a mandatory activity to further study the rheology of polymer in porous media.
Tanjung structure is geologically located in northern Barito Basin. It has seven productive zones including six sandstone zones A, B, C, D, E, F and one volcanic zone P. This field began production in 1961 and reached peak primary production of 50,253 STB/D in 1963. Currently, Tanjung Field Zone-C is proposed as a candidate for polymer flooding application using polymer Flopaam 3630S based on extensive evaluation in laboratory scale. To further characterize its behavior in Tanjung Zone-C reservoir, a-month injectivity test is planned. In this study, we present the step-by-step activity to design the proper injectivity test for Tanjung Field Zone-C reservoir.
Polymer is a Non-Newtonian fluid whose viscosity decreases in increasing shear rate. It is different with water behavior whose viscosity is stable over various shear rate. Rheometer measurement that was conducted for early investigation of polymer rheology can only characterize the shear-thinning regime of polymer behavior over various shear rate.
However, in porous media, shear-thickening and mechanical degradation are critical phenomena which affect the ability of polymer to enter the porous media and perforated layer. Therefore, core injectivity experiments were conducted as an attempt to capture the shear-thinning, shear-thickening and mechanical degradation behavior of polymer in porous media. Because shear-thinning is a fluid characteristic, shear-thinning in rheometer and core injectivity test should be match.
By combining the rheometer and core injectivity test to validate reservoir simulation, one can obtain the proper method to be implemented in the field test. Finally, these proposed method can be used to improve field injectivity test design which will be implemented this year.