Carbon Accounting and Data Integrity

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Environmental Overview

+ Carbon Accounting and Data Integrity

Helping our customers achieve net-zero goals requires effective carbon accounting and data collection processes to help them make decisions to manage their energy waste that align with good environmental stewardship objectives. Milestone’s focus on responsible energy waste management delivers emissions-reducing results. Over the last few years, we have worked towards refining our carbon accounting and data collection methods to accurately measure and communicate the benefit we provide to customers.

In 2020, Milestone conducted a sequestration analysis of samples collected from our slurry injection stream to determine the average total petroleum hydrocarbon (TPH) content. The analysis examined the carbon dioxide equivalent sequestration impact of our slurry injection disposal practices in comparison to the traditional practice of land application disposal. Through collaboration with an independent third-party consulting firm, we developed a methodology for estimating this comparison.

Overview of GHG protocol scopes and emissions across the value chain

*Greenhouse Gas Protocol, Corporate Value Chain (Scope 3) Accounting and Reporting Standard. Source


Managing Emissions across the Value Chain

In 2021, we continued this collaboration to implement a comprehensive waste sampling protocol that offers Milestone and our customers improved insight in understanding the GHG impact of all E&P waste. We collected, analyzed, and verified samples categorized by waste types, i.e., produced water, flowback, oil-based mud, water-based mud, tank bottoms, etc. Based on analysis of these samples, the average barrel of slurry waste (i.e., excluding produced saltwater and flowback water) injected by Milestone contains approximately 49 kilograms of CO2e per barrel (kg CO2e/bbl).3 One hundred percent of the TPH contained in our injection stream is permanently sequestered in deep, further refined, secure formations.

During 2022, Milestone further refined the implemented program, with the help of nationally recognized environmental consultants, to align our process and procedures with international best carbon accounting practices. We also expanded the role of our financial accounting firm, who performed certain agreed upon procedures as part of our triple-verified process.

See Appendix III in our 2021 Sustainability Report for an executive summary of the study we previously conducted, which outlines our measurement methodology for the emissions and sequestration impacts of our slurry injection process.4

3 Per our historical volume data, approximately 3.5% of slurry receipt volume consists of non-injectable solids (e.g., cuttings) that are removed via surface equipment and sent offsite for disposal.

4 The methodology in Appendix III in our 2021 Sustainability Report is based on TPH content for waste received in 2021. Milestone incorporated TPH sampling results from 2022 to quantify emissions and sequestration impacts for 2022.