Oil/gas drilling and the environment

By Engr. Edgar Mana-ay

The fossil fuel industry or oil and gas drilling, where Texas is at the forefront, is not disappearing any time soon but in fact, will increase in the next 20 years despite its deleterious effects on the environment.

The issue of climate change (read: global warming) due to carbon emission from the use of fossil fuels has never been scientifically settled. To the consternation of global warming advocates, society cannot put its act together as shown by the failure in the various UN-sponsored conferences of nations known as Conference of Parties now on its 26th meeting (COP 26) to reduce oil and gas consumption.

If we slash the use of oil and gas too quickly, we will cause economic hardships on the poor and trigger protests like the Yellow Vest movement in France. But if we don’t also cut consumption fast enough, global warming advocates say we will heat the planet and create a climate disaster unless the world can totally shift to clean energy such as solar and wind which this writer believes is not possible in the next 100 years.

Before that transition and while there is still a boom in oil and gas, the industry should not evade from its responsibility to reduce emission and all forms of pollution to the environment in its process of getting the oil and gas under the earth. It should also take it as a responsibility and opportunity to lead the transition to a cleaner, more efficient and more sustainable, lower carbon society.

One of the environmental resources greatly affected by fracking drilling (refer to my previous articles on fracking) is water. Oil and gas wells drilled in the Permian Basin in West Texas produces almost 5 million barrels (1 barrel is 159 liters) of oil per day plus a substantial amount of natural gas. A shallow sea that existed millions of years ago, the Permian Basin of West Texas and Southeastern New Mexico, is the US’s largest and most active oil field today.

During the first two months of an oil well’s life, most of the water that comes out of the surface is used during the drilling and hydraulic fracturing process known in the industry as “flow back.” BUT after that, most of the water that comes out with the oil and gas comes from the geological formation itself that has been fractured to release the trapped oil, gas and water and this amounts to about 4 TO 10 BARRELS OF ANCIENT, SALTY AND CONTAMINATED WATER OUT OF THE HOLE FOR EVERY BARREL OF OIL PRODUCED!

According to the U.S. Department of Energy, beginning February when the Permian Basin starts producing 4.8 million barrels per day of oil, the region is expected to receive about 15 million barrels of wastewater per day. Why is this so? Hundreds of millions of years ago, the sedimentary basin had trapped/preserved hydrocarbon materials (plants, trees, animals) and water at the same time. Because of the long residence time at very deep strata of 12,000 ft. or more,  this ancient trapped water becomes very salty (termed as connate water) at TDS or total dissolved solids of more than 50,000 while DOH standard for drinking water is only 500 TDS and seawater normally is at 20,000 TDS. During fracking operation, this water cannot just be discharged in a nearby river (even if there is one) or flood surrounding land because it is pollutant laden and brine in nature. I had the experience of drilling in Bislig, Surigao Sur where very salty water came out at depth of only 400 ft. resulting in the destruction of a hectare of rice fields nearby.

This writer had also drilled two wells in Pavia at a relatively shallow depth of only 200 ft. but encountered mild salty water (about 2,000 TDS). The probability of saltwater intrusion from the sea towards Pavia is very low and probably (?) this might be ancient water. The accurate residence time of water in an aquifer can only be confirmed with the use of environmental isotope hydro-geology by applying the law of radioactive decay. The radioactive isotopes of water: tritium- 3H, carbon- 14C and chlorine- 36Cl together with the noble inert gasses (Ne, Ar, Kr, Xe) are useful in providing an estimate of aquifer residence time. The combined interpretation of environmental isotope and noble gas data will assist in the reconstruction of paleoenvironmental conditions existing at that time and give insights into the history of aquifer evolution, hence its age in years.

In the disposal of this tremendous amount of very salty and polluted wastewater, the fracking industry started with re-injecting it back deep underground at disposal sites known as saltwater disposable wells at more than 12,000 ft. depth. While it will not affect shallow freshwater aquifer, many believed it is causing the minor earthquakes now prevalent in the Permian Basin drilling area. Because of this, the oil and gas industry is now trying a new on-site disposal method called the Carrier Gas Concentration (CGC) technology. The equipment is modular can be installed alongside a well.

CGC technology is basically receiving the wastewater, filter out oil, natural gas, chemicals, and other contaminants. The water is then heated at the low-pressure environment (if you are in an airplane 10,000 ft. above sea level, water boils at only 90 degrees C and not at 100°C) to the point of evaporation and the resulting steam is released to the atmosphere. No need to go into rain seeding because 10 to 15 million barrels of water vapor or “clouds” a day are pumped into the atmosphere.

Everything else is left behind as super-concentrated brine that can be either disposed of or used to plug wells at the end of their life. The released steam becomes part of the water vapor in the atmosphere or clouds in simple terms and will later go back to earth as rain. So far rain received in the area does not contain polluting compounds from oil such as benzene, cadmium, formaldehyde, hexane, toluene, and lead.