– The following table summarizes our future estimated office lease payments for periods subsequent to December 31, 2018. The leases pertain to approximately 15,000 square feet of space for our corporate headquarters in Midland, Texas, approximately 3,700 square feet of office space for our accounting offices in Tulsa, Oklahoma and approximately 2,000 square feet of office space for our field office in Andrews, Texas. The Company incurred lease expenses of $524,060, $543,770 and $527,582 for the years ended December 31, 2018, 2017 and 2016, respectively. The following table reflects the future minimum lease payments under the operating leases as of December 31, 2018.