What We Do

Energy Industry in Transition

Global carbon emissions from fossil fuels have significantly increased over the last century, especially in the last 50 years. Since 1970, carbon dioxide (“CO2”) emissions have increased by about 90%, with fossil fuel combustion and industrial processes contributing about 78% of the total greenhouse gas (“GHG”) emissions increase from 1970 to 2011.3 In 2019, United States GHG emissions totaled 6,558,000 metric tons (“MT”) of CO2e.4

A circular diagram showing how Milestone is working to reach its goal of net-zero.

Energy companies are under pressure from investors and the public to reduce their GHG emissions and advance the transition to a low-carbon economy. It will take multiple concurrent paths to drive towards net zero and achieve the aggressive goals that have been set.

Currently, energy waste is not a significant part of the net-zero conversation. We are working to change that. Milestone provides an immediately available, proven, and low-cost means to channel energy waste and reduce carbon impact during the exploration and production of energy. Our solutions give energy producers another lever to pull in their pursuit of net-zero goals.

A diagram of prisms meausring global emissions by source and oil and gas share.

*Organization for Economic Operation and Development (OECD), EIA, European Commission Join Research Center

Changing the Perspective on Energy Waste

Drilling fluids, produced water, and other wastes are inevitable byproducts in the exploration, development, and production of oil and gas. This waste is regulated at the state level by agencies, including the Texas Railroad Commission (“TXRRC”) and the New Mexico Oil Conservation Division (“NMOCD”), and is exempt from hazardous designation under the Resource Conservation and Recovery Act of 1978 (“RCRA”). These energy waste streams contain hydrocarbons, water, chlorides, and heavy metals that emit GHG when exposed to air and sunlight. If not handled properly, energy waste contaminates soil and groundwater.5

A circular diagram showing all the components that make up energy waste.

While most technologies and processes at drilling sites have advanced, waste management practices have not. E&P companies habitually employ reserve pits and land application to dispose of waste. Although regulations in certain states permit these practices, these outdated methods pose enormous environmental and economic risks to our E&P customers and the communities in which they operate. E&P companies frequently bury liquid and solid wastes in reserve pits near drilling sites. These pits often have no protective liners installed and are not monitored for integrity on an ongoing basis. Through a process called land application, oilfield waste is spread in a six-inch layer over a portion of a farm or ranch and tilled into the soil. This common, traditional practice can emit 300 MT CO2e per new well drilled.6  

Milestone provides solutions that allow our E&P customers to mitigate the risk of soil and groundwater contamination and reduce operational carbon impacts. Our business gives energy companies a path to go beyond minimum regulatory compliance with a better, cleaner way to address this waste.

Milestone manages a variety of energy waste streams for its customers, including drilling fluid (“mud”), drill cuttings, other slurries, produced and flowback waters, production tank bottoms, and contaminated soils. Milestone’s customers primarily generate these waste streams in the drilling, completion, and production phases of the oil and gas extraction lifecycle.

An aerial view of reserve pits in the Permian Basin

An  aerial view of reserve pits in the Permian Basin.

Maps Data: Google, ©2021

Drilling Waste

E&P companies pump drilling mud down the drill string to lubricate the bit during downhole rotation. Drilling mud is comprised of an oil or water base, emulsifiers, brine, dispersants, and/or gels. As the bit rotates, circulation and pressure of the fluid system moves rock fragments up the wellbore to the surface, where it is processed in a nearby reserve pit (or in a series of storage and separation tanks in a “closed-loop” regulatory system). Approximately 20% of drilling mud is recycled back into the fluid system for future use. Depending on the jurisdiction, the remainder is either disposed of onsite through land application or transported to a permitted disposal facility. 

Milestone’s slurry injection facilities are designed to handle drilling waste that is primarily liquid in nature. Our surface equipment extracts a small fraction of residual solids from the mud and slurry volume we receive, which we send to our landfills or others located nearby. Our landfills handle both solid and liquid waste streams. To prevent leakage at our landfills, we utilize a dehydration or bulking process for liquid waste streams before disposing of them.

Completion and Production Waste

Most E&P companies use a reservoir stimulation technique called hydraulic fracturing, commonly known as frac’ing. Frac’ing involves pumping a mixture of water, chemicals, and sand at high pressures into the productive reservoir through perforations in the wellbore. The resulting production stream—comprised of hydrocarbons, completion fluid “flowback” and produced saltwater—flows to the surface, where hydrocarbons are separated from the waste byproducts. E&P companies often send a portion of produced saltwater and flowback to an in-field water treatment facility for reuse in future frac’ing operations. Sediment and water regularly accumulate at the bottom of storage tanks and require periodic removal (called “tank bottoms.”) Our customers send drilling mud, tank bottoms, other slurries, produced saltwater, and flowback, to one of our Class II underground injection control (“UIC”) wells for disposal.7 Milestone’s slurry injection facilities carry both UIC Class II and solid waste management permits issued by the TXRRC and NMOCD.

Pump in Midland, Texas

3Source: https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data

4Source: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks

5 Source: Guidelines for Commercial Exploration and Production Waste Management Facilities, March 2001: https://www.api.org/-/media/Files/EHS/Environmental_Performance/E_P_Waste_Guidelines.pdf

6 Assumes a horizontal well design with three strings of casing, 10,000-foot productive lateral length, and 60% recycling of oil-based drilling mud. See methodology for measuring the carbon content and conversion to GHG emissions in CO2e in Appendix II.

7 Vacuum trucks are used for transportation of produced water and flowback if production tank batteries are not connected to a water pipeline system.