Depreciation, Amortization and Accretion Expenses
Depreciation, amortization and accretion expense for the three and nine months ended September 30, 2024 as compared with the three and nine months ended September 30, 2023 slightly increased due to higher depreciation expense related to new assets placed in service.
Abandoned Well Costs
See Item 1. Financial Statements ─ Note 4. Property, Plant and Equipment.
General and Administrative Expenses
General and administrative (“G&A”) expenses increased $3.9 million for the three months ended September 30, 2024 as compared with the three months ended September 30, 2023 primarily due to a $1.8 million increase in stock-based compensation expense, which was $4.9 million and $3.1 million for the three months ended September 30, 2024 and 2023, respectively. The remaining increase in G&A expenses during the three months ended September 30, 2024 primarily related to higher compensation and benefits expenses related to higher headcount, higher legal fees and higher IT expenses.
G&A expenses increased $9.9 million for the nine months ended September 30, 2024 as compared with the nine months ended September 30, 2023, primarily due to a $4.2 million increase in stock-based compensation expense, which was $12.6 million and $8.4 million for the nine months ended September 30, 2024 and 2023, respectively. The remaining increase in G&A expenses during the nine months ended September 30, 2024 primarily related to higher compensation and benefits expenses related to higher headcount, higher legal fees, higher IT expenses and higher office rent expense primarily related to our new corporate office lease.
Research and Development Expense
Research and development expense is related to the development of technologies for the beneficial reuse of produced water. Research and development expense decreased for the three months ended September 30, 2024 as compared with the three months ended September 30, 2023 due to Coterra Energy Inc. joining the JIP in the third quarter of 2024 and the costs being split equally among alliance members, as described above. Research and development expense increased for the nine months ended September 30, 2024 as compared with the nine months ended September 30, 2023 due to internal beneficial reuse research and development, as well as the JIP.
For the three months ended September 30, 2024 and 2023, total research and development expense related to the JIP, which is split equally among alliance members, was $2.0 million and $1.8 million, respectively. For the nine months ended September 30, 2024 and 2023, total research and development expense related to the JIP, which is split equally among alliance members, was $7.2 million and $3.9 million, respectively.
Other Operating (Income) Expense, Net
Other operating (income) expense, net includes net gains and losses on asset sales, abandoned projects, transaction costs and other expenses. See Item 1. Financial Statements ─ Note 3. Additional Financial Statement Information and Note 4. Property, Plant and Equipment.