First let me identify myself by saying I am in the oil and gas industry. That being said, I also have some experience in sequestering CO2 into subsurface formations. CO2 injection into reservoirs that contain oil is another way to get more oil and gas out of the ground that would otherwise be left behind. After primary production we normally produce around 30% of the oil in place. Then we go to what is called secondary production and get anywhere from 20 to 30% more of the original oil in place. Percentages vary depending on the type of reservoir rock we are producing from. Now we can inject slugs of water followed by slugs of CO2 into the reservoir. This sweeps more oil from around the injection wells over to the producing wells. Again, depending on the type of reservoir rock we can get upwards to another 20 to 30% of the original oil inplace. This greatly enhances the amount of oil we can produce. It is not cheap to do this, but the value of the oil out weighs the cost of gathering the CO2, compressing it and injecting it into the ground. Eventually, the CO2 "breaks through" to the producing wells. We separate the gases from the oil and water produced by the wells. We sell the oil and we re-inject the water and the CO2 to repeat the process.
While I am not a believer in man-induced global warming I am a believer in the use of CO2 as a tertiary means to produce more oil. It works and the country is better off for the technology. As for environmental damages to the groundwater, today's wells are drilled and completed to protect all groundwater sources. The industry takes it very seriously when it comes to protecting the environment despite what the national press may tell you. I've dealt with the press several times I can attest to the fact the majority have no clue what they are talking about, be it oil or other environmental issues. There are seveal layers of steel casing cemented into the ground to protect ground and surface waters. We do not want to risk endangering anyone's drinking water and we do not want to throw away money in the form of lost oil and gas or the costs to remediate contaminated soils and water. As for getting the CO2 to our wells, we can pipeline it to the fields. This is being done every day just as we pipe natural gas to your homes and businesses. We very seldom have releases to the atmosphere and should a leak occur we have blocking valves to isolate the leaks in a line until repairs can be made. It is very safe and reliable. I have no qualms about using CO2 as a means to produce more, much needed, domestic oil and we can do it safely and responsibly.