X0306 4 2020-10-01 0 0001486159 Oasis Petroleum Inc. OAS 0001502361 Lorentzatos Nickolas J 1001 FANNIN ST, STE 1500 HOUSTON TX 77002 0 1 0 0 Executive VP, GC & Corp. Sec. Common Stock 2020-10-01 4 S 0 271073 0.23 D 108086 D On the Form 4 filed by the Reporting Person on March 4, 2019, a total of 472 shares of Common Stock were incorrectly reported as having been withheld to satisfy tax withholding obligations in connection with the vesting and settlement of certain performance share units. As a result, the number shown in this column reflects an additional 472 shares of Common Stock that were beneficially owned and sold by the Reporting Person since such shares were not actually withheld to satisfy tax withholding obligations. Represents weighted average price of open market same day sales. Sales of shares took place at actual prices ranging from $0.21 to $0.24 per share. Full information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, Oasis Petroleum Inc. or an Oasis Petroleum Inc. shareholder. /s/ Nickolas J. Lorentzatos 2020-10-02