Our customers are primarily oil and natural gas exploration and production companies, which are collectively exposed to oil and natural gas commodity price risk. Our customers require services from us at various stages of the exploration and production process. Accordingly, we have aggregated our trade receivables by segment. We utilize an accounts receivable aging schedule and historical credit loss information to estimate expected credit losses. We evaluate our accounts receivable periodically through review of historical collection experience, current aging status of the customer accounts, financial condition of our customers, and the overall economic environment of the oil and gas industry. Any customers that have experienced a deterioration in credit quality are removed from the pool and evaluated individually.

During 2021, we reversed $1.5 million of our credit loss provision related to certain customers who had previously experienced a deterioration in credit quality. Since initially recording loss provisions for these receivables, we have collected portions of the accounts that were deemed uncollectible. During 2022, we wrote-off $5.6 million of our credit loss provision related to certain customers, as we reached final settlements.

The allowance for credit losses related to accounts receivable as of December 31, 2021 and 2022, and changes for the periods ended December 31, 2021 and 2022 are as follows (in thousands):


Balance at December 31, 2020	$	10,842
Provision for expected credit losses		(1,500	)
Write-offs		(849	)
Balance at December 31, 2021		8,493
Write-offs		(5,618	)
Balance at December 31, 2022	$	2,875