CLB 2018 Annual Report

F-16 2018 2017 Original life in years Gross Carrying Value Accumulated Amortization Gross Carrying Value Accumulated Amortization Acquired trade secrets 2-20 $ 3,604 $ 2,110 $ 3,390 $ 1,765 Acquired patents and trademarks 4-15 9,697 3,115 5,406 2,274 Agreements not to compete 2-5 1,149 759 839 782 Acquired trade names Indefinite 4,588 — 4,582 — Total intangibles, net $ 19,038 $ 5,984 $ 14,217 $ 4,821 Our estimated amortization expense relating to these intangibles for the next five years is summarized in the following table (in thousands): 2019 $ 1,322 2020 $ 1,120 2021 $ 911 2022 $ 888 2023 $ 593 8. GOODWILL The changes in the carrying amount of goodwill for each reportable segment for the years ended December 31, 2018 and 2017 were as follows (in thousands): Reservoir Description Production Enhancement Total Balance at December 31, 2016 $ 99,484 $ 79,560 $ 179,044 Goodwill acquired during the year — — — Balance at December 31, 2017 99,484 79,560 179,044 Goodwill allocated to discontinued operations — (915) (915) Goodwill acquired during the year — 41,283 41,283 Balance at December 31, 2018 $ 99,484 $ 119,928 $ 219,412 9. LONG-TERM DEBT, NET We have no capital lease obligations. Debt at December 31, 2018 and 2017 is summarized in the following table (in thousands): 2018 2017 Senior Notes $ 150,000 $ 150,000 Credit Facility 142,000 78,000 Total debt 292,000 228,000 Less: Debt issuance costs (2,230) (1,011) Long-term debt, net $ 289,770 $ 226,989 In 2011, we issued two series of senior notes with an aggregate principal amount of $150 million ("Senior Notes") in a private placement transaction. Series A consists of $75 million in aggregate principal amount of notes that bear interest at a fixed rate of 4.01% and are due in full on September 30, 2021. Series B consists of $75 million in aggregate principal amount of notes that bear interest at a fixed rate of 4.11% and are due in full on September 30, 2023. Interest on each series of the Senior Notes is payable semi-annually on March 30 and September 30. On June 19, 2018, we entered into an agreement to amend our revolving credit facility ("Credit Facility"). To appropriately size the facility, the aggregate borrowing commitment was reduced from $400 million to $300 million. The Credit Facility provides an option to increase the commitment under the Credit Facility by an additional $100 million to bring the total