Ann: Annual Report, page-14

All things being equal, the Amortisation Expense should normally follow the BOE Production Numbers, as the asset/infrastructure is amortised in line with the income/production it generates.

My analysis shows that Amortisation Expense has increased from around $9 per BOE produced for 2021FY and 2022FY to $13 per BOE produced in 2023FY - almost a 40% increase.

It may be that:
a) The amortisation expense charged for 2021FY & 2022FY was understated for some reason and that a "Catch Up" was done in 2023FY.
b) The cost of the infrastructure/assets has gone up significantly due to various inflation/supply issues, with no increase in the BOE that the infrastructure/assets will produce over their life.
c) BRK have adopted an amortisation model that increases the allocation of expenses in the earlier years of a well, with a subsequent reduction in expenses in the latter years of the well.

I have asked a similar question on the Investor Website.