Since the advent of shale development twenty years ago, producers have struggled to come up with an enhanced oil recovery process that proved itself economically.

Any technique that could boost oil recovery from the current 10 – 11 percent of oil-in-place for shale wells up to the mid-teens while keeping the cost down would be “the golden ticket,” said an engineering consultant.

Recently, an EOR pilot program at Occidental Petroleum in the company’s field near Hobbs, NM, was described in an article published by Bloomberg. In the pilot, several dozen wells are used to inject a water and carbon dioxide mix into the shale in order to push crude through the formation.

Water, steam, CO2 , NO2 and natural gas have all been used in EOR test programs for the past decade to find the right combination of pressure, temperature, and chemistry needed to economically coax additional barrels out of tight shale formations. Until now, the attempts have proven either inconclusive or uneconomic.

According to the news report, the company expects to increase recovery to 17 – 18 percent as a conservative estimate. “When you consider the scale of the Permian, to do that will be amazing,” said Vicki Hollub, Occidental CEO.

The company’s pilot project is testing both push-and-pull EOR where the water-CO2 mix is injected in one well and oil pumped at another, and testing a single well for injection and recovery. Chevron is also testing shale EOR in the Permian, the report noted.

Chevron is said to have extensive experience with EOR in mature oil fields in California.

Using carbon dioxide in EOR carries the added benefit of sequestering a greenhouse gas from the atmosphere.

In January, Occidental reported it partnered with Chevron to financially support a Canadian clean energy company in developing a low-cost method for pulling CO2 from the air for use in EOR projects.

Such technology “opens a pathway to producing fully carbon-neutral or even net-negative fuels,” according to a release from Occidental.

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