oil recovery

Polymer flooding can help improve sweep efficiency from oil wells. In order to maximize oil recovery, specialty chemical firms can develop better polymers and fluids for polymer floodingImage Source: Flickr user CL.Baker

Transitions can be difficult, and as once-productive oil wells are steadily depleted, it has become  increasingly important for oil companies to maximize sweep efficiency. One way to do this is through polymer flooding, a well-established enhanced oil recovery method in which soluble polymers are added to flood water in order to make it more viscous.

This improves the mobility ratio, which makes it possible to recover more oil. Recent research suggests that there are ways to improve the fluids used in polymer flooding in order to increase the efficiency of the process. Improving the chemical composition of these fluids by utilizing innovative software and informatics systems, specialty chemical firms can help oil companies maximize yield.

Identifying the Best Polymers for Polymer Flooding

Oil companies typically choose between a few common soluble, high molecular weight polymers when preparing the polymer slug to be used for flooding. Some of the most common include xanthan and hydrolyzed polyacrylamide, but these polymers are sensitive to salinity, temperature, shear, and biological degradation.1  It’s time for specialty chemical firms to start searching for better polymers. Modern software can help researchers mine existing data about polymer slugs in order to identify the most significant weaknesses of common polymers. Based on this information, they can design focused experiments and develop alternative polymers that are more effective for oil recovery.

In the past, efforts to improve polymers have stalled for economic reasons. Either the individual monomers were too expensive for widespread use, or the polymer production process cost too much.2  To overcome these problems, researchers need to be able to integrate sweep efficiency and economic data to conduct high-level cost-benefit analyses. These calculations can be facilitated by software solutions that make it possible to determine which alternative polymers are economically feasible. That way, researchers won’t waste time testing or developing polymers that are too expensive or don’t significantly improve sweep efficiency.

Finding Ways to Improve the Fluids Used in Polymer Flooding

Improving polymers is important, but specialty chemicals firms must also consider the fluid that is used in the polymer slug. Pure water may not be the best choice. Studies indicate that adding chelating agents such as sodium NTA or sodium EDTA to the slug can increase the amount of oil recovered from a well.3  Another way to improve sweep efficiency is to lower the salinity level of the polymer slug. Not only does this increase oil recovery by increasing polymer elasticity, but it also cuts costs by reducing the amount of polymer that needs to be added to the slug in order to reach the target viscosity.4  Using simulation software, scientists can model slugs that have different salinity levels or added chemicals in order to determine which ones maximize the oil recovery when combined with a certain polymer. Software can also facilitate data integration so that specialty chemical firms can factor in polymer properties and economic information when choosing between different fluid options.

Another way to increase sweep efficiency, especially in high salinity oil reservoirs, is to inject a preflush, or water slug, before the polymer slug. Studies indicate that using a solution with a high pH as the preflush can improve efficiency, but there is room for further research to find new options. Chemical researchers can examine how different chemicals for lowering the acidity can affect sweep efficiency and overall costs. Through mining existing datasets, scientists may also be able to identify other properties of the preflush that could be changed to increase its effectiveness. Using modern modeling and simulation technology, scientists can test potential preflush alternatives and integrate results with economic data to find an optimal preflush solution.

The Benefits of Collaboration Between Lab Scientists and Field Researchers

The primary way for those chemists developing more effective polymers and fluids to find out how well their solutions work in particular environments is to collaborate with researchers in the field. By considering environmental data, it may be possible for lab scientists to develop chemical combinations that are optimized to particular oil well environments. Experimental software can make it easy for lab and field scientists to share data and results in real-time so that the teams in both locations can design and conduct relevant tests and simulations. It also mediates the seamless integration of chemical, environmental, and economic data so that specialty chemical companies can develop fluids for polymer flooding that are optimized for all three factors.

BIOVIA Experiment, a laboratory informatics system for data management and analysis, and BIOVIA Materials Studio, a modeling and simulation environment, can be invaluable for chemical specialty firms that are looking to improve polymer flooding methods. These systems can help your company identify and develop polymers and fluid combinations that increase sweep efficiency and won’t be too expensive for practical use. Contact us today to learn more about the difference this software can have on your research and development processes.

  1. “Polymer Flooding,” 2016, http://www.glossary.oilfield.slb.com/Terms/p/polymer_flooding.aspx
  2. “Development of a Novel Waterflood Conformance Control System,” April 2004, https://www.onepetro.org/conference-paper/SPE-89391-MS
  3. “Improved Micellar/Polymer Flooding With High-pH Chemicals,” January 1981, https://www.onepetro.org/journal-paper/SPE-7583-PA
  4. “Improving polymer flood performance in high salinity reservoirs,” March 2014, http://www.sciencedirect.com/science/article/pii/S0920410514000266