Deposits of oil and natural gas in porous layers of rock and shale often occur alongside large quantities of saltwater. In order to bring these resources to the surface for further production, oil and gas companies must first remove the surrounding saltwater, which is also known as produced water or oilfield brine. This liquid contains high levels of salt as well as industrial compounds and hydrocarbons. While there are various ways to dispose of the saltwater and flowback fluid resulting from hydraulic fracturing, improper disposal may pose a threat to subterranean and aboveground fresh water.
Firms may choose to recycle the saltwater via evaporation or distillation. However, these processes often require a significant, consistent flow of water in order to serve as financially viable disposal strategies. While this is possible in regions with a large number of producing wells and an established saltwater pipeline infrastructure, recycling does not account for 100 percent of saltwater disposal, thus necessitating additional disposal methods.
Oil and gas companies may opt to use saltwater disposal wells, injecting the saltwater into non-producing underground formations of porous rock. This practice requires layers of impermeable strata both above and below the disposal well to protect shallow fresh water and is used extensively throughout Texas, where it falls under the jurisdiction of the Railroad Commission of Texas. The agency has mandated that saltwater disposal wells must contain several layers of cement and steel to protect usable fresh water at shallow depths, and it has outlined three distinct layers of well casing. The commission also restricts the establishment of saltwater disposal wells to locations that already contain naturally occurring saltwater.
In 2014, an international leader in pipeline maintenance and emission management introduced an innovative new strategy for detecting oil and gas pipeline leaks. Based in Belgium, The Sniffers has worked to detect and analyze leaks in pipelines and industrial equipment since 1991. It recently launched its dogs division, employing a team of trained canines to facilitate hazard detection around the world. Each dog receives certification from Technischer Ueberwachungsverein, a German safety assessment organization, after successfully completing 40 simulations in natural settings. Working in pairs, The Sniffers’ dogs are able to cover large distances and traverse rural and agricultural terrain, in addition to offering shorter leak detection times and increased accuracy. While most state-of-the-art oil and gas leak-detection tools measure pollutants at parts per million, The Sniffers’ dog division is capable of detecting leaks at parts per billion.
Since the division’s inception, The Sniffers’ leak-detection dogs have examined thousands of kilometers of varying terrain, including mountains, rivers, highways, and suburban developments. In addition to locating safety hazards related to oil and gas production, the canines can also detect explosives, narcotics, and underground short circuits. They have been successful in detecting water leaks in Japan, and have worked to detect illegal pipeline tapping in Georgia, where they identified the first illegal tap in less than four hours.
Approximately half of the earth’s remaining oil reserves exist in limestone reservoirs. Using three-dimensional X-ray technology to study the ways in which oil and other liquids flow through rock, scientists from the University of Edinburgh and Heriot-Watt have conducted research that may increase our potential to recover oil from these deep rock formations.
Published in Proceedings of the National Academy of Sciences, the study received support from Petrobas and BG Group. The team of scientists and engineers carried out the research as part of the International Centre for Carbonate Reservoirs program, eventually discovering a previously undetected naturally occurring characteristic of oil that may aid its recovery from subterranean rock deposits. Researchers detected the process occurring within limestone’s complex pore structure, noting that it allowed oil droplets trapped in porous rock to move more easily though pore networks. During the process, flowing water breaks oil droplets into small fragments, thus making it easier to recover.
This development could increase oil reservoir yields and is especially applicable to operations in complex, multi-scale reservoir pore systems, such as those found in the pre-salt carbonate oil fields of Brazil. It also has the potential to help treat contamination in natural aquifers and aid the development of carbon capture and storage techniques.
In the oil and gas industry, a Pugh Clause allows lessors to relinquish ownership of land not undergoing production activities at the end of the primary lease term or at the end of continuous drilling operations. It derives its name from Lawrence Pugh, a Louisiana lawyer who first drafted the clause in 1947 in response to the Louisiana Supreme Court’s decision in Hunter v. Shell Oil Co., which held that production from a leased unit will maintain the lease in force for all leased land, even for regions that are not contiguous or producing oil, gas, or minerals.
Also known as a freestone rider, a Pugh Clause allows lessors to avoid maintaining ownership of a lease’s full acreage while only producing on a small portion of the land. In such a situation, a lessor would receive no production revenue or royalties from undeveloped land, but would still maintain indefinite ownership of the undeveloped acreage under the original lease terms. A Pugh Clause prevents this anomaly by allowing for the termination of ownership of land that is not producing oil, gas, or minerals and is not otherwise maintained by the lease. Additionally, it exists in two variations. A vertical Pugh Clause releases all land below a specified depth or particular producing zone, while a horizontal Pugh Clause facilitates the release of lands lying outside of a producing unit, at both the surface and all depths.