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The Role of the Landman in Oil and Gas Operations

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A Primer on Saltwater Disposal Wells

Many oil and natural gas deposits are trapped in environments alongside water, and wells that are constructed to exploit these resources require techniques to handle the wastewater, also known as “saltwater,” “oilfield brine,” and “produced water,” that the extraction process brings up to the surface. Generally, the resources are mixed with the water and must be extracted. The remaining saltwater has to be carefully managed, and the Environmental Protection Agency places strict limits on its disposal. While companies are increasingly turning to injection wells, where the saltwater is recycled for use in extracting further natural gas or oil through hydraulic fracturing, the management of these fluids still requires care, and saltwater disposal wells have been designed specifically to contain them.

Generally, the goal of a saltwater disposal well is to ensure that the saltwater never interacts with the groundwater or the outside environment. In one state, Texas, the requirement for these kinds of wells states that three layers must be used: surface casing, production casing, and protection casing. The outermost layer, the surface casing, is steel and concrete that starts at the surface and descends all the way to the deepest groundwater layer. Next, the production casing takes the form of a pipe cemented to the wellbore, followed by the protection layer, with its injection tubing string. These components bring the water underground, where it remains safely stored in underground geologic formations.

What is Fracking?

Presented by Sentry Energy

In recent years, there has been a lot of interest in the process of hydraulic fracturing in the extraction of natural gas. Here, Sentry Energy explains how fracking works and why gas companies so frequently use the technique.

Also known as hydraulic fracturing, fracing, and hydrofracking, fracking is the process by which a rock layer can be cracked using fluid pressure. The process is usually used to increase the extraction rates and ultimate recovery of oil and natural gas. By opening up cracks in reservoir rock formations, energy professionals can greatly expand the yield of a given well or reservoir. Companies utilize the technique in around 90 percent of natural gas wells in the United States.

When fracking a well, gas companies inject a pressurized mixture of water, chemicals, and a proppant, such as sand, to hold the fractures open after ending the injection, so gas can travel to the surface. Hydraulic fracturing requires a very specific variety of sand. With very small, round particles of nearly pure quartz, the sand contains few impurities and does not disintegrate when pumped underground and put under the pressure inherent in the process. Companies conduct most fracking in horizontally drilled wells through shale reservoirs. Shale is particularly impermeable deep in the earth and the stimulating effects of fracking enable gas extraction. Companies create some reservoirs, such as the Bakken, Barnett Shale, Haynesville Shale, and Montney, almost exclusively through fracking and multistage completion systems.

While professionals engage in fracking in this country mostly to stimulate production in oil and gas wells, others employ the technique to stimulate groundwater wells, precondition rock for caving, enhance waste cleanup processes, dispose of waste, or measure the stress in the earth.