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## Cash and Cash Equivalents 

Cash and cash equivalents include all short-term, highly liquid instruments purchased with an original maturity of three months or less. These items are carried at cost, which approximates fair value. 

## Concentration of Credit Risk 

Our financial instruments that potentially subject us to concentrations of credit risk relate primarily to cash and cash equivalents and trade accounts receivable. All cash and cash equivalents are on deposit at commercial banks or investment firms with significant financial resources. Our trade receivables are with a variety of domestic, international and national oil and gas companies. We had no clients who provided more than 10% of our revenue for the years ended December 31, 2013, 2012 and 2011. We consider our credit risk related to trade accounts receivable to be limited due to the creditworthiness and financial resources of our clients. We evaluate our estimate of the allowance for doubtful accounts on an on-going basis throughout the year. 

## Accounts Receivable 

Trade accounts receivable are recorded at their invoiced amounts and do not bear interest. We perform ongoing credit evaluations of our clients and monitor collections and payments in order to maintain a provision for estimated uncollectible accounts based on our historical collection experience and our current aging of client receivables outstanding, in addition to client’s representations and our understanding of the economic environment in which our clients operate. Based on our review we establish or adjust allowances for specific clients and the accounts receivable as a whole, and recognize expense. When an account is determined to be uncollectible, we charge the receivable to our allowance for doubtful accounts. Our allowance for doubtful accounts totaled $2.9 million and $3.5 million at December 31, 2013 and 2012, respectively. The net carrying value of accounts receivable is considered to be repre- sentative of its respective fair value. 

## Inventories 

Inventories consist of manufactured goods, materials and supplies used for sales or services to clients. Inventories are stated at the lower of cost or estimated net realizable value. Inventory costs are recorded at standard cost which approximates the first-in, first-out method. 

## Prepaid Expenses and Other Current Assets 

Prepaid expenses and other current assets are comprised primarily of current deferred tax assets, prepaid insurance, value added taxes and prepaid rents. 

## Property, Plant and Equipment 

Property, plant and equipment are carried at cost less accumulated depreciation. Major renewals and improvements are capitalized while maintenance and repair costs are charged to expense as incurred. They are depreciated using the straight-line method based on their individual estimated useful lives, except for leasehold improvements, which are depreciated over the remaining lease term, if shorter. We estimate the useful lives and salvage values of our assets based on historical data as follows: 

<img src='content_image/180406.jpg'>

When long-lived assets are sold or retired, the remaining costs and related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in income. These capitalized long-lived assets could become impaired if our operating plans or business environment changes. 

We review our long-lived assets, including definite-lived intangible assets, for impairment when events or changes in circumstances indicate that their net book value may not be recovered over their remaining service lives. Indicators of possible impairment may include significant declines in activity levels in regions where specific assets or groups of assets are located, extended periods of idle use, declining revenue or cash flow or overall changes in general market conditions. 

Whenever possible impairment is indicated, we compare the carrying value of the assets to the sum of the estimated undiscounted future cash flows expected from use, plus salvage value, less the costs of the subsequent disposition of the assets. If impairment is still indicated, we compare the fair value of the assets to the carrying amount, and recognize an impairment loss for the amount by which the carrying value exceeds the fair value. We did not record any material impairment charges relating to our long-lived assets held for use during the years ended December 31, 2013, 2012 or 2011. 

