Acidizing

What Is Acidizing?

In the oil and gas extraction industry, acidizing is a technique used to extend the useful life of an oil and gas well. The process of acidizing involves pumping acid into the well in order to dissolve the rocks that line the contours of the well. 

Acidizing increases production rates by creating channels into the rock through which the oil and gas can flow into the reservoir. An additional benefit of acidizing a well is that it can help dissolve any loose debris found in the well.

How Acidizing Works

Acidizing is often employed to extract the remaining resources from oil wells that have reached the end of their productive lives. Indeed, because it is a relatively expensive process to employ, acidizing will only be used once simpler methods, such as primary recovery techniques, have been fully utilized. If the price of oil is not sufficiently high to justify the investment, a company may forego acidizing and simply move on to a younger well that can produce oil and gas more cheaply.

According to the American Petroleum Institute, the basic practice of acidizing has been widespread for nearly 120 years. In the 1930s, its popularity waned as a result of the damage it could do to the steel linings of the wells. In subsequent years, however, corrosion inhibitor technologies were developed that effectively prevented this damage. This has led acidizing to once again be widely used in the oil and gas services industry.

Acidizing may be more useful than hydraulic fracturing in some situations. Hydraulic fracturing–also called fracking–is a process that creates channels in underground rock formations by injecting a mixture of water and fracking chemicals into the well at very high pressures. Unlike hydraulic fracturing, acidizing does not require the same high-pressure injections. Rather, acidizing relies on the acid substance to dissolve any permeable sediments in the well.

In regions where underground shale deposits are not uniformly arranged–for example in regions with substantial tectonic activity, such as the state of California–acidizing may prove to be more effective at unlocking oil deposits than hydraulic fracturing. However, in some cases, both methods are used in tandem. This process is known as acid fracking.

Special Considerations

The types and concentrations of acids used in the acidizing process are often not disclosed by the companies that manufacture them, although hydrochloric and hydrofluoric acids have been known to be used. Because of this ambiguity, it can be difficult to accurately assess the safety and environmental risks associated with the practice.

One area of special concern is the potential impact that the practice of acidizing can have on the groundwater in the surrounding area. Damage to well linings could potentially lead to acidizing chemicals spilling into surrounding water sources, potentially threatening the local ecosystem or surrounding population centers.

Despite these potential risks, acidizing faces fewer regulations than other oil and natural gas production techniques. Some states, such as California, have passed legislation to increase regulation on the practice and potentially impact individuals who are heavily invested in oil and gas exploration companies.