Oil and gas reservoirs are usually found in porous rocks, which also contain saltwater. This saltwater, which accompanies the oil and gas to the surface, can be disposed in two ways: 1) Returned by fluid injection into the reservoir where it originated for secondary or enhanced oil recovery; or 2) Injected into underground porous rock formations not productive of oil or gas, and sealed above and below by unbroken, impermeable strata. Saltwater disposal wells use this second method to manage saltwater.
Operators are responsible for disposing of produced water and frac fluid. Frac fluid is used to fracture and stimulate natural gas wells in certain areas of Texas, such as the Barnett Shale natural gas play near Fort Worth. Water or frac fluid is used to fracture tight shale to release gas trapped in the shale.
Specifically, a disposal well’s construction standards require three layers of casing to ensure groundwater is protected. The first protection layer is surface casing—a steel pipe that is encased in cement that reaches from the ground surface to below the deepest usable quality groundwater level. Surface casing acts as a protective sleeve through which deeper drilling occurs. The second protection layer is the production casing—a pipe placed in the wellbore to the well’s total depth and permanently cemented in place. The third protection layer is the injection tubing string and packer that conducts the injected water down through the injection tubing string and production casing to perforations at the bottom of the well to inject the water into an underground formation. With this well construction, all three protection layers must fail at the same time to impact groundwater.
If a permit is technically complete, it may be administratively approved by the Railroad Commission’s technical staff. However, if a permit is protested, a hearing is required to be held and based on evidence presented during the hearing, a staff proposal for decision (PFD) recommending approval or denial of the permit will be issued. The staff PFD then goes to the three Railroad Commissioners for final consideration.
FOR MORE INFORMATION ON Salt Water Disposal Well Ownership Go To ENERGY EQUITY GROUP.