Scaling Up Smart Water

Rassenfoss, Stephen (JPT Emerging Technology Senior Editor)

OnePetro 

Middle East Special Section

For nearly a decade, Saudi Aramco has been studying how altering the chemical makeup of seawater injected into its reservoirs can increase production. The result is an increasingly complex view of the interactions caused by the makeup of seawater that explains why seawater does more than just add pressure and help sweep the remaining oil out of a reservoir.

The goal is to cost-effectively maximize production by altering the chemistry of seawater. Hundreds of technical papers have been written on the potential benefits of reducing the salinity in seawater injected into formations.

More recently there has been a growing body of work on how other ingredients found in seawater—particularly sulfate, calcium, and magnesium—can add to oil output by freeing oil from reservoir rock.

Saudi Aramco has focused its research, dating back to 2008, on how seawater is able to increase production from carbonate reservoirs. Two recent technical papers from Saudi Aramco show that it has begun considering how it might modify its water treatment system to turn seawater into “smart water” (SPE 179564), and also offers an update on laboratory studies investigating how the active ingredients in seawater affect oil production (SPE 179590).

What is clear from those papers and other sources is that seawater, which Saudi Aramco turned to as a cheap option to scarce fresh water, can enhance the amount of oil ultimately recovered from the ground. The research also suggests that it can make seawater more effective by altering its chemical makeup, turning it into smart water. But this option is neither simple nor cheap.

Reducing the salinity of the extremely salty seawater used by Saudi Aramco would require desalination on a massive scale. Further changes to make it smart water add processing steps and may require new technology to reduce the energy required and to overcome the fact that available water treatment methods were not designed to selectively remove ingredients from water.

Turning seawater into smart water is a logical next step for the company, which has long been processing seawater on a huge scale to maintain production from its fields. Its Al-Qurayyah Sea Water Plant processes millions of barrels a day of seawater, removing small particles, microorganisms, and oxygen. Now the company has begun considering whether to add further processing steps to apply what it has learned about seawater chemistry by fine-tuning the makeup of the water.