2021 ] CARBON CAPTURE , UTILIZATION , AND SEQUESTRATION 51
B . Primary Disposal and Sequestration Processes and Select CO 2 Infrastructure
As noted above , a CCUS system must not only capture and separate CO 2 but also either store , dispose of , or utilize the captured CO 2 to prevent its release into the atmosphere . All of these methods require the CO 2 to be captured before release into the atmosphere in order to eliminate or decrease harmful CO 2 emissions that would have otherwise occurred . This portion of the paper will examine : ( 1 ) the application of CO 2 for EOR operations , ( 2 ) CO 2 EOR as an environmental mitigation strategy , ( 3 ) the application of CO 2 for sequestration proprojects , and ( 4 ) a review of select CO 2 infrastructure .
1 . Application of CO 2 for EOR Operations
Today , the most common commercial use for CO 2 is its application for EOR operations in the oil and gas industry . An oil field ’ s development occurs in several phases . Once the field is initially brought online , the natural pressure from the reservoir pushes the oil to the surface (“ primary recovery ”). However , as the oil is produced , the reservoir ’ s natural pressure decreases , and recovery becomes more difficult . As operators lose pressure from their reservoir , they deploy a process called “ secondary recovery .” During secondary recovery , operators inject substances ( mostly water ) into the reservoir to help maintain the pressure so that oil continues to flow to the surface . Although this process is called secondary recovery , as noted below , advances in horizontal drilling and hydraulic fracturing now allow many operators to use these methods as part of their initial development process . Much like primary recovery , the increased pressure achieved after the deployment of secondary recovery operations eventually dissipates , and in some instances ( dependent upon reservoir and field characteristics ), this pressure may be restored with the injection of gas ( including CO 2 ) into the applicable reservoir or field . This process is known as “ tertiary recovery .”
Despite developments in hydraulic fracturing and other enhanced recovery techniques , it is estimated that between 70 %– 85 % of the oil originally in place at the time of discovery will remain stranded in the reservoir . 35 One solution is to pump pressurized CO 2 into the depleted reservoir . As a result , a new fluid is formed with lower viscosity and surface tension , and the remaining oil deposits are more easily displaced . 36 In other words , the CO 2 scours the geological
35 . L . STEPHEN MELZER , CARBON DIOXIDE ENHANCED OIL RECOVERY ( CO2 EOR ): FACTORS INVOLVED IN ADDING CARBON CAPTURE , UTILIZATION AND STORAGE ( CCUS ) TO ENHANCED OIL RECOVERY 3 ( Feb . 2012 ), https :// carboncapturecoalition . org / wpcontent / uploads / 2018 / 01 / Melzer _ CO2EOR _ CCUS _ Feb2012 . pdf .
36 . JAMES P . MEYER , SUMMARY OF CARBON DIOXIDE ENHANCED OIL RECOVERY ( CO2 EOR ) IN-
JECTION WELL TECHNOLOGY 1 , https :// www . api . org /~/ media / Files / EHS / climate-change / Summarycarbon-dioxide-enhanced-oil-recovery-well-tech . pdf .