11. ASSET RETIREMENT OBLIGATIONS

The following table summarizes the changes in our asset retirement obligations:



Accretion is recorded in the line item “Depreciation, depletion and amortization” on our condensed consolidated statements of operations.

We are required under the Etame PSC to conduct regular abandonment studies to update the estimated costs to abandon the offshore wells, platforms and facilities on the Etame Marin block.  In 2018, we recorded a downward revision of $6.5 million to the ARO liability as a result of a change in the expected timing of the abandonment costs when the period of exploitation under the Etame PSC was extended to at least September 16, 2028 as discussed further in Note 10.  The most recently completed abandonment study was in November 2018.