Optimizing Small Volume of Block Co-Polymers Used for Enhanced Oil Recovery

Optimizing Small Volume of Block Co-Polymers Used for Enhanced Oil Recovery

Read how DLS-based optical microrheology can be used to determine the rheological behavior of polymer solutions and the impact of tracer particle chemistry on the measured microrheological response.

Introduction

Enhanced Oil Recovery (EOR) is gaining increasing attention due to the shortage of current oil resources and difficulties in finding new oil fields. With traditional methods, only about 20–40% of oil is extracted from a newly drilled oil reservoir leaving 60–80% oil in the reservoir. With EOR technology, an additional 20% oil can be obtained from the reservoir. Polymers, especially surfactant and hydrogel polymers play an important role in the application of EOR technology [1]. The most common polymer used for this application is from the polyacrylamide group. These EOR fluids are used to implement polymer flooding - the injection of a solution into porous rock surrounding a drilled well, to recover residual oil.

The rheological properties of the EOR fluid play a critical role in the overall performance of these fluids. Quick rheological measurements over a wide frequency range are often required.  In addition, especially in the case of newly synthesized polymers that are being tested for EOR applications, sample volumes available for testing are limited. Microrheology, which involves tracking the motion of dispersed tracer particles of known size by Dynamic Light Scattering (DLS), is a new and emerging technique that can be utilized to further scope the rheological performance of enhanced oil recovery (EOR) fluids such as hydrolyzed polyacrylamide and xanthan gum solutions. An additional benefit is that only small volumes of sample are required to give access to a rheological response over a wide frequency range [2, 3].