Flaring of gas wells is one of those processes connected with natural gas development that most people find rather fascinating, but many don’t well understand. Even fewer have heard of what is already gradually replacing flaring and will soon totally replace it; something called green completions. Questions, therefore, abound. The majority of these questions center on why flaring or green completions are necessary.
The water used during the process is held in the formation, after a well is hydraulically fractured. NaturalGasNOW.org is published from the Marcellus Shale region where the shale is so dry the shale starts to imbibe this water. If left in the formation too long, the water absorbed into the rock will cause it to swell–think of a dry sponge sitting in a pool of liquid. The pathways for the natural gas to move are cut off as the rock swells; the overall production of the well diminishes.
The well is opened up to allow water to flow back to surface so it is not imbibed. However, natural gas also surfaces with the water. Venting natural gas directly into the atmosphere is not an option because natural gas or methane (CH4) is a known greenhouse gas. Moreover, under certain weather conditions, natural gas can concentrate in a single area creating a hazardous situation. Therefore, a method is needed to control this surfacing gas.
Flaring is commonly used in situations when no pipeline line is available to flow the gas to sales. During the process of flaring, the rising gas and water are effectively separated and the gas is burned off. Through combustion of natural gas, CO2 and H2O are created but CO2, though a greenhouse gas like CH4, is less impactful on the environment and poses no hazard.
If a pipeline is available to take gas to sales, the natural gas is not flared off. instead, it is separated from the water and put it to a pipeline (see above). This method is called “cleaning up into sales” in industry parlance, “reduced emissions completions” to regulators and “green completions” to others. Researchers from the University of Texas at Austin, in 2012, observed 67% of wells already sent methane to sales. Northeastern Pennsylvania gas companies have also been using this technique ever more steadily. Here is an example of the portable equipment often used in the field.
What makes this method a greener alternative to flaring is that no unnecessary green house gases of any kind are emitted while the well flows back its water. Gas companies also prefer this method of green completions for the simple reason that it captures more natural gas to sell. Here’s the basic process compared to flaring: