DOE completes SPR degassing program

The U.S. Energy Department has completed a 2-year program to remove excess natural gas that had accumulated in parts of the Strategic Petroleum Reserve. Removal of the gas will permit the 563 million bbl SPR, which is held in four salt dome cavern locations along the Gulf Coast, to be drawn down at a rate of nearly 4 million b/d. In 1993, DOE discovered that methane from the surrounding salt formations had intruded into about 172 million bbl of oil that had been stored the longest.

Jan. 19, 1998

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The U.S. Energy Department has completed a 2-year program to remove excess natural gas that had accumulated in parts of the Strategic Petroleum Reserve.

Removal of the gas will permit the 563 million bbl SPR, which is held in four salt dome cavern locations along the Gulf Coast, to be drawn down at a rate of nearly 4 million b/d.

In 1993, DOE discovered that methane from the surrounding salt formations had intruded into about 172 million bbl of oil that had been stored the longest.

The dissolved gas posed a potential safety problem when the oil was pumped to the surface during a drawdown. Exposed to atmospheric pressure, methane vapors could escape and possibly explode. The condition limited the SPR drawdown rate to 2 million b/d for a while.

In August 1995, DOE began pumping the affected oil to the surface, degasifying it, and reinjecting it. The operation was completed Dec. 13, 1997, about 4 months ahead of schedule.

The department said it may need to cycle stored oil through degassing equipment about every 10 years.

Changing SPR sites

DOE also is in the last stages of transferring crude from the Weeks Island SPR site near New Iberia, La. It is being decommissioned due to intrusion of surface water, and DOE has removed all but 2 million bbl of the 72 million bbl once stored there.

Early this year, it will complete a remotely controlled, underground skimming operation that is removing a 5-in. thick layer of oil floating on brine that has been injected into the cavern.