Building a Strong Sustainable Oasis: Our New E&P Model

January 2021

A New Tomorrow, Today

A New Tomorrow, Today Nasdaq: OAS Forward-Looking / Cautionary Statements

Forward-Looking Statements Non-GAAP Financial Measures This presentation, including the oral statements made in connection herewith, contains forward-looking statements Cash Interest, Adjusted EBITDAX, E&P Cash G&A, Free Cash Flow, Adjusted Net Income (Loss) Attributable to Oasis, Adjusted within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of Diluted Earnings (Loss) Attributable to Oasis Per Share and Recycle Ratio are supplemental financial measures that are not 1934. All statements, other than statements of historical facts, included in this presentation that address activities, presented in accordance with generally accepted accounting principles in the United States (“GAAP”). These non-GAAP measures events or developments that the Company expects, believes or anticipates will or may occur in the future are should not be considered in isolation or as a substitute for interest expense, net income (loss), operating income (loss), net cash forward-looking statements. Without limiting the generality of the foregoing, forward-looking statements contained in provided by (used in) operating activities, earnings (loss) per share or any other measures prepared under GAAP. Because Cash this presentation specifically include the expectations of plans, strategies, objectives and anticipated financial and Interest, Adjusted EBITDAX, Free Cash Flow, Adjusted Net Income (Loss) Attributable to Oasis, Adjusted Diluted Earnings (Loss) operating results of the Company, including the Company’s ability to capitalize on its emergence from restructuring Attributable to Oasis Per Share and Recycle Ratio exclude some but not all items that affect net income (loss) and may vary among and to implement its realigned initiatives and strategies, the Company's drilling program, production, derivative companies, the amounts presented may not be comparable to similar metrics of other companies. Reconciliations of these non-GAAP instruments, capital expenditure levels and other guidance included in this presentation. When used in this financial measures to their most comparable GAAP measure can be found in the annual report on Form 10-K, quarterly reports on presentation, the words "could," "should," "will,“ "believe," "anticipate," "intend," "estimate," "expect," "project," the Form 10-Q and on our website at www.oasispetroleum.com. Amounts excluded from these non-GAAP measure in future periods negative of such terms and other similar expressions are intended to identify forward- looking statements, although could be significant. not all forward-looking statements contain such identifying words. These statements are based on certain assumptions made by the Company based on management's experience and perception of historical trends, current conditions, anticipated future developments and other factors believed to be appropriate. Such statements are Cautionary Statement Regarding Oil and Gas Quantities subject to a number of assumptions, risks and uncertainties, many of which are beyond the control of the Company, The Securities Exchange Commission (the “SEC”) requires oil and gas companies, in their filings with the SEC, to disclose proved which may cause actual results to differ materially from those implied or expressed by the forward-looking reserves, which are those quantities of oil and gas, which, by analysis of geoscience and engineering data, can be estimated with statements. When considering forward-looking statements, you should keep in mind the risk factors and other reasonable certainty to be economically producible—from a given date forward, from known reservoirs, and under existing economic cautionary statements described under the headings “Risk Factors” and “Cautionary Statement Regarding Forward- conditions (using unweighted average 12-month first day of the month prices), operating methods, and government regulations—prior Looking Statements” included in the Company’s filings with the Securities and Exchange Commission. These include, to the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, but are not limited to changes in oil and natural gas prices, weather and environmental conditions, the timing of regardless of whether deterministic or probabilistic methods are used for the estimation. The accuracy of any reserve estimate planned capital expenditures, availability of acquisitions and divestitures and the ability to integrate acquisitions into depends on the quality of available data, the interpretation of such data and price and cost assumptions made by reserve engineers. its existing business, uncertainties in estimating proved reserves and forecasting production results, operational In addition, the results of drilling, testing and production activities of the exploration and development companies may justify revisions factors affecting the commencement or maintenance of producing wells, access to and terms of credit in the of estimates that were made previously. If significant, such revisions could impact the Company’s strategy and future prospects. commercial banking and other debt markets, the condition of the capital markets generally, as well as the Company's Accordingly, reserve estimates may differ significantly from the quantities of oil and natural gas that are ultimately recovered. The ability to access them, cash flows and liquidity, the proximity to, availability of, and capacity of transportation facilities, SEC also permits the disclosure of separate estimates of probable or possible reserves that meet SEC definitions for such reserves; and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments however, we currently do not disclose probable or possible reserves in our SEC filings. affecting the Company's business and other important factors. In addition, the Company’s forward-looking statements address the various risks and uncertainties associated with the extraordinary market environment and impacts Proved reserves at December 31, 2019 are estimated utilizing SEC reserve recognition standards and pricing assumptions based on resulting from the novel coronavirus 2019 pandemic and the actions of foreign oil producers to increase crude oil the trailing 12-month average first-day-of-the-month prices of $55.85 per barrel of oil and $2.62 per MMBtu of natural gas. The production and the expected impact on our business, operations, earnings, and results as well as the risks and reserve estimates for the Company are based on reports prepared by DeGolyer and MacNaughton ("D&M"). uncertainties associated with the impact of the Company’s ability to respond to such risks on its actual results. Should one or more of these risks or uncertainties occur, or should underlying assumptions prove incorrect, the Our production forecasts and expectations for future periods are dependent upon many assumptions, including estimates of Company’s actual results and plans could differ materially from those expressed in any forward-looking statements. production decline rates from existing wells and the undertaking and outcome of future drilling activity, which may be affected by significant commodity price declines or drilling cost increases. Any forward-looking statement speaks only as of the date on which such statement is made and the Company undertakes no obligation to correct or update any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by applicable law.

A New Tomorrow, Today Nasdaq: OAS 2 A Stronger Oasis Aligned with Shareholder Interests

Returns-Focused ESG Leadership Business Model

High Quality Assets Strong Strategic Generating Significant Direction Aligned Free Cash Flow with Shareholders

Best-in-Class The Right Team Balance Sheet to Execute

A New Tomorrow, Today Nasdaq: OAS 3 New Oasis Built for the New Environment

New Oasis New Environment Today’s Oasis has an industry leading financial profile tailored to the new environment. We are  Best-in-class balance sheet (p. 9)  Generate free cash flow and focused on generating free cash competitive shareholder returns (p. 8) flow and delivering competitive  New business model focused on shareholder returns with our low- returns  Understanding the energy transition cost assets. and its opportunities  New board of directors, with WILLISTON BASIN enhanced governance, aligned  Embracing environmental, social and 404k Net Acres | 56.1Mboepd1 with shareholders (p. 7) governance initiatives (p. 6)

 Quality asset base delivering  Alignment of management incentives significant free cash flow  Consolidation to build scale and  Material Midstream value & relevance optionality (p. 14) PERMIAN BASIN 24k Net Acres | 9.5Mboepd1

1) Production as of 3Q20 A New Tomorrow, Today Nasdaq: OAS 4 Near-Term Strategic and Financial Priorities

. Free cash flow generation (after capital program)

. Planning to return capital to shareholders this year New Business Model . Returns above cost of capital and target leverage <1.0x (Debt/EBITDA)

. Established capital allocation Board committee to systematize new business model

. Initiated extensive third-party review of cost structure and organizational efficiency Operational Excellence . Targeting new material operating cost and capital efficiencies

. Strong commitment to safety, diversity & inclusion and community

. Refreshed, diverse and independent board of experienced industry professionals ESG Leadership . Compensation will be value creation focused, and aligned with shareholders

. Further our best-in-class emissions capture

. Analysis of existing E&P portfolio for fit with new business model Portfolio Review . Review Midstream for value creation opportunities

. Opportunistically improve position through value-enhancing consolidation Industry Consolidation . Improve financial strength, investment quality, cost of capital, investment relevance

A New Tomorrow, Today Nasdaq: OAS 5 Implementing ESG Initiatives And Best Practices

Environmental, Health and Safety Human Capital Governance

. Best in Class Gas Capture . Comprehensive benefits including health . New Board of Directors care for employees at every level in the – Flared gas percentage ~2/3 less than organization and retirement plan dollar – 83% independent peer average in North Dakota matching – Diverse industry-leading experts across – Capture gas for other operators, multiple disciplines . Oasis Academy for Success learning reducing industry-wide emissions system supports job-specific training – Declassified Board

. Strong record of fluid and emission . Soft skill and leadership development and . Established Nominating, Environmental, containment training Social & Governance Committee to . Environmental impact of our operations . Committed to our Communities oversee ESG policies and initiatives complemented by control of extensive . Directors to be elected by a majority of infrastructure – Deeply involved in the areas in which we work and are active votes rather than plurality . 16% per year reduction in reportable spills . Special meetings may be called by (2015-2019) – Employees involved in broad range of charitable organizations in ND & TX shareholders representing 25% or more of outstanding shares – Work with NextOp to attract US Military veterans for open positions at Oasis . No supermajority voting requirements

. Implemented compensation practices aligned with shareholders Note: More details on our ESG initiatives can be found on the Oasis website: www.oasispetroleum.com

A New Tomorrow, Today Nasdaq: OAS 6 New Board Driving Our Strategic Plan

Independent, Douglas E. Samantha F. John D. N. John Robert J. Cynthia L. Brooks Holroyd Jacobi Lancaster, Jr. McNally Walker experienced and

OAS Roles / Board Chair Lead Independent; Chair of Comp; Comp; A&R; Chair of A&R; aligned with Committees1 and CEO Chair of NESG1; A&R NESG NESG Comp NESG shareholders Industry Leadership - Marathon Oil - Golden Advisors - Javelin Energy - Oyster Creek - EQT - Occidental - Energy XXI - Lantana Energy - Jacobi-Johnson - Riverstone - EQM Midstream - Goldman Sachs - Yates Petroleum - TPG Sixth Street - Covey Park - CSFB - Precision Drilling 83% Independent - Aurora Oil & Gas - Denham - Warrior Energy - Royal Dutch Shell - Simmons & Co . New Board provides an updated perspective Current and Previous - California Resources - Gulfport Energy - Pioneer Energy - Liberty Oilfield - Warrior Energy - Sempra Energy Board(s) - Chaparral Energy - Comstock Resources - Magellan Midstream - Dalbo Holdings . 33% of directors are - Madalena Energy - Cobalt International - EQT women - Energy XXI - Summit Midstream - Yates - Aurora Oil & Gas Average of 30+ years Current or past public of industry experience company CEO or C-suite ✓ ✓ ✓ ✓ . Leadership roles across E&P/Midstream ✓ ✓ ✓ ✓ ✓ ✓ upstream, midstream, Operations oil services, investing, Capital ✓ ✓ ✓ ✓ ✓ ✓ banking, advising and Allocation/Investment finance Environmental, health and safety management ✓ ✓ ✓ ✓

Mergers and acquisitions ✓ ✓ ✓ ✓ ✓ ✓

A New Tomorrow, Today 1) NSEG - Nominating, Environmental, Social & Governance Committee, A&R – Audit and Reserves. Comp – Compensation Nasdaq: OAS 7 Generating Significant Cash Flow to Benefit Shareholders

25% 1,2,4,5 22% 2021E FCF Yield

20% 19% Invest well within cash flow 17% 17% 16% . Rigorous capital discipline focused 15% 13% on corporate level returns 11% 10% . Reinvestment rate significantly below 9% 10% 8% cash flow 6% . Production growth an output rather 5% 4% than an input Return capital to shareholders 0% . Board evaluating return to shareholder alternatives and -5% opportunities -5% . Potential to pay a meaningful -10% -9% dividend

-15% Maintain strong balance sheet and low leverage . Leverage target: <1x . Current leverage ratio: 0.6x6 Significant FCF Yield and Leverage Below Targeted Levels

1) FactSet consensus and Oasis Petroleum Cleansing Materials 2) Peer FCF defined as consolidated/estimated cash from operations minus CapEx. Peer Group: CDEV, CLR, CPE, LPI, MTDR, NOG, PDCE, PE, QEP, RRC, SM, WLL WPX 3) “OAS” reflects unlevered FCF estimates from Cleansing Materials filed 9/30/2020 adjusted for cash interest/taxes 4) OAS share count reflects 20MM shares outstanding plus 2.4MM shares associated with management incentive program (see slide 18 for portion allocated). All share prices as of 12/31/2020 5) Oasis to provide 2021 guidance concurrent with 4Q2020 reporting 6) 12/31/2020 figures reflect unaudited estimates of Oasis’s debt and cash balance as of that date and may differ from the cash and cash equivalents and long-term debt balances in the Company’s audited financial statements prepared in accordance with GAAP A New Tomorrow, Today Nasdaq: OAS 8 Best-in-Class Balance Sheet Supports New Business Model

Net Debt / Annualized 3Q20 Unhedged EBITDAX1

7 6.3 6 2 5.2 New Capital Structure Highlights 5 4.6 Equity 3.8 4 3.5 3.7 AVERAGE: 3.1X . 20MM shares of common stock 2.8 2.9 3 2.5 . 60MM shares authorized 1.8 2.0 2 . 2.4MM shares reserved for LTIP (see slide 18 for portion 1.0 OAS 1 0.6 Target: allocated) <1.0X . 1.6MM warrants – exercise price of $94.57 0 OAS A B C D E F G H I J K L Debt and Cash3

. $575MM RBL facility

Robust Hedging Program Minimizes Downside Risk . $260MM drawn on 12/31/2020

. LIBOR + 300-400 bps with 100 bps floor WTI Oil Hedging 2021 2022 2023 . $6.8MM of LCs Mbopd 29.0 19.0 14.0 st Weighted Avg WTI Swap Price $42.09 $42.74 $43.68 . 1 redetermination – 4/1/2021 . Matures – May 2024 HH Gas Hedging MMBtu/d Price . Leverage ratio covenant < 3.0x EBITDAX (TTM) Dec '20 - Dec '21 10,000 $2.92 . $10.7MM of cash on 12/31/2020 Dec '20 - Jun'22 30,000 $2.82

. 1) Peer Group: CDEV, CLR, CPE, LPI, MTDR, NOG, PDCE, PE, QEP, SM, WLL WPX 2) Excludes OMP capital structure, as OAS and OMP debt are not cross collateralized and guarantors under OAS credit facility are not responsible for OMP debt 3) 12/31/2020 figures reflect unaudited estimates of Oasis’s debt and cash balance as of that date and may differ from the cash and cash equivalents and long-term debt balances in the Company’s audited financial statements prepared in accordance with GAAP A New Tomorrow, Today Nasdaq: OAS 9 Driving Better Margins And Increased Capital Productivity

Aggressively Managing Proactive E&P Cash G&A 2020 Capital Budget Costs per Boe in 20201 Reductions2 ($MM) Reductions3 ($MM)

$21.59 % $1.37 17 $595 $3.38 $17.92 27% $575 % $2.16 58 $2.17

$9.12

$6.84 $67 $248

$49 $243

$7.72 $6.75

2Q20 3Q20 2020 Budget Current Run Rate Original Plan New Plan E&P E&P LOE E&P GM&T & Diffs Low High E&P Cash G&A Production Taxes

1) See appendix for details. E&P Costs do not include any benefit from midstream cash flows that return to Oasis, which are reflected in chart “Midstream Cash Flows to OAS.” 2) Cash G&A excludes restructuring and professional fees as well as costs associated with RIF in 2020 3) Reflects E&P & Other Capital: Other capital includes administrative capital, but excludes capitalized interest. E&P CapEx excludes acquisitions

A New Tomorrow, Today Nasdaq: OAS 10 Compelling Valuation for OAS Shareholders

OAS EV($MM)1,4 OAS Adjusted EBITDAX($MM)2 Compelling Valuation3 3Q20A Annualized OAS EBITDAX Ex-hedges EV/EBITDAX (2021E) $1,079 $432 8

7 6.7 $249 OMP $53 OAS RBL Distributions 6 5.5 5.6 5.7 5.2 5.3 Drawn Less 5 4.5 Cash Retained 4.3 3.8 3.8 midstream $79 4 3.7 3.2 3.3 3 2.5 2

1

0 $830 E&P OAS Market EBITDAX $300 Capitalization Attractive EV/EBITDAX Valuation Compared to E&P Peers at ~4.5x3

3Q20

1) Market cap reflects 20MM shares + 2.4 MM shares associated with management incentive program (see slide 18 for portion allocated) x price on 12/31/20; OAS has $260MM drawn on RBL with $10.7MM of cash as of 12/31/2020 2) See Definitions of all non-GAAP measures and reconciliations to their most comparable GAAP measure can be found on the Oasis website at www.oasispetroleum.com. E&P EBITDAX excludes midstream ownership credits which are included in consolidated GAAP financials. DevCo portion of EBITDAX reflects retained interest in Bobcat and Beartooth DevCos. OMP distributions reflect distributions for Oasis’s ownership of OMP units and OMP GP. 3) OAS EBITDAX is 3Q20 annualized and defined as E&P EBITDAX + OMP distributions + DevCo EBITDA, peers based on 2021E (from Factset); Peer Group: CDEV, CLR, CPE, LPI, MTDR, NOG, PDCE, PE, QEP, RRC, SM, WLL WPX. As of 12/31/20 4) 12/31/2020 figures reflect unaudited estimates of Oasis’s debt and cash balance as of that date and may differ from the cash and cash equivalents and long-term debt balances in the Company’s audited financial statements prepared in accordance with GAAP A New Tomorrow, Today Nasdaq: OAS 11 Bakken – Cornerstone Asset

Competitive Advantages 404k Net Acres . Contiguous core asset with . Strong FCF from proven / 87% of OAS production and highly predictable asset 56.1 strong cash margins base Mboepd1 . One of the largest . Peer leading well cost and % producers and acreage performance 92 holders Operated2

71% 10+ Years of Top-Tier Inventory Working Interest2 Drives Free Cash Flow

1) Production as of 3Q20 2) Percent operated and working interest is based on producing wells

A New Tomorrow, Today Nasdaq: OAS 12 Permian – Premier, Multi-Stacked Oil Focused Asset

Competitive Advantages 24k Net Acres . Repeatable, capital efficient . Strong inventory and compelling deployment economics

9.5 . Advantaged geologic position Mboepd1 . Optimizing parent-child . Oil-rich and multi-stacked pay relationships and flow back % zones 99 . Improving well costs & overall 2 Operated – 80%+ oil mix capital efficiency 92% Extensive Multi-Stacked Inventory in the Core Working Interest2 of the Delaware Basin

1) Production as of 3Q20 2) Percent operated and working interest is based on producing wells

A New Tomorrow, Today Nasdaq: OAS 13 Midstream Position Generates FCF and Creates Optionality

Oasis Midstream Partners (OMP) Position

. Significant (~68%) ownership position in top tier midstream company

. OMP is a leading owner, developer, operator and acquirer of a diversified portfolio of midstream assets in North America

. Generates significant distributions with strong coverage and balance sheet

. Third party customers provide significant revenue and additions will be a priority for future

Retained Midstream Interests

. Receives meaningful cash flow from retained DevCo ownership interest

Evaluating Optimal Structure and Value Creation Options

A New Tomorrow, Today Nasdaq: OAS 14 A Stronger Oasis Aligned with Shareholder Interests

Returns-Focused ESG Leadership Business Model

High Quality Assets Strong Strategic Generating Significant Direction Aligned Free Cash Flow with Shareholders

Best-in-Class The Right Team Balance Sheet to Execute

A New Tomorrow, Today Nasdaq: OAS 15 Appendix

A New Tomorrow, Today Nasdaq: OAS 16 Highly Experienced Management Team

. Senior management team with extensive expertise in the oil and gas industry NIKO DOUG BROOKS TAYLOR REID MICHAEL LOU Board Chair & Chief President & Chief LORENTZATOS EVP & Chief Financial Officer . Deep knowledge of Executive Officer Operating Officer EVP General Counsel and Corporate Secretary Oasis’ business

. 39 years of oil & gas . COO since inception . CFO or similar . GC since 2010 industry experience in 2007 capacities since 2009 . Brings differentiated . 21 years of oil & gas and advanced skills in . Previously CEO at . 35 years of oil & gas . 23 years of oil & gas industry experience Yates Petroleum, industry experience industry experience identification, acquisition Aurora Oil and Gas . Senior Counsel with and execution of and Energy XXI . Multiple positions at . 10 years energy Targa Resources, resource conversion Conoco Phillips and investment banking ConocoPhillips and opportunities . Multiple positions at Burlington Resources Burlington Resources Marathon Oil . CFO of private E&P company

A New Tomorrow, Today Nasdaq: OAS 17 NEO Compensation Aligned with Shareholders

Compensation Guiding Principles1,2 . Promote strong pay for performance alignment; realized gains will be predicated on both absolute and relative shareholder value creation Vesting schedule . Offer significant, front-loaded potential wealth creation opportunities, contingent upon delivering . Award and vesting schedules longer superior absolute and relative shareholder value (no grants expected in 2022 or 2023) than industry peers . Motivates and engages management to better navigate over the long-term in a volatile industry . Time horizon consistent with and macro market environment assessing long-term value creation % of Vesting Type Description Total Time

3 Dependent on absolute TSR measured 3-4 Returns driven Leveraged Stock Unit 50% against specific return objectives years . Superior absolute and relative TSR performance required (respectively) – Dependent on relative TSR measured 3-4 for awards to be earned Relative PSU against peers (50%) and a broad market 25% years

PSUs PSUs index (50%) Broad market benchmark 4 years . Component of PSU award tied to Time Vested Promotes retention of key executives 25%

ratable broad market index RSUs . Benchmarking the company against Cash Compensation Changes broader universe of investment alternatives . Executive base salaries reduced

1) Full details of compensation program can be found in form 8-K filed with SEC on January 21, 2021; 167,012 RSU shares have been granted to board and NEOs and 191,148 PSUs/LSUs have been granted to NEOs 2) PSU = Performance Share Unit, TSR = Total Shareholder Return, LSU = Leveraged Stock Unit, RSU = Restricted Stock Unit 3) PSUs – TSR grants will be measured on a three-year basis (50%) and four-year basis (50%)

A New Tomorrow, Today Nasdaq: OAS 18 Incentives Aligned with Long-Term Value Creation1 Vesting Schedule Time-Based 100% 25% 25% 25% 25% RSUs RSUs - 4 year ratable vesting

50% 100% Relative TSR Relative TSR PSU - Peers PSUs vs. . 50% 3 year and 50% 4 year vesting Industry Peers 50% 100% . Measured on cumulative TSR over period vs peers

Relative TSR 50% 100% PSUs vs. Relative TSR PSU - Index General . 50% 3 year and 50% 4 year vesting Industry Index 50% 100% . Measured on cumulative TSR over period vs general market index peers 50% 100% Absolute TSR Absolute TSR PSU/LSU PSUs/LSUs 50% 100% . 50% 3 year and 50% 4 year vesting . Measured on absolute TSR following four quarterly measurement periods Jan. 2021 Jan. 2022 Jan. 2023 Jan. 2024 Jan. 2025 prior to vesting periods Initial Grant No Grant No Grant Normal Grant TBD Normal Grant TBD Longer Vesting Schedules and Stringent Returns Criteria Differentiate Oasis’s Compensation Program

1) Full details of compensation program can be found in form 8-K filed with SEC on January 21, 2021

A New Tomorrow, Today Nasdaq: OAS 19 Oasis 3Q20 Financial and Operational Results See slide 19 for reconciliations Financial Highlights ($MM) Key Operating Statistics ($MM) Oil Revenues 155.1 Oil Production (Bopd) 43,748 Gas Revenues 14.8 Gas Production (Mcfpd) 130,981 Total Oil & Gas Revenue 169.9 Total Production (Boepd) 65,578 Other Services Margin (0.0) NYMEX WTI ($/Bbl) 40.96 Realized Oil Price 38.52 Purchased Oil and Gas margin (2.6) Realized Hedges 80.2 NYMEX Henry Hub ($/mmBtu) 1.99 Other Income / non-cash adjustments 1.6 Realized Gas Price 1.23 Operating Costs Operating Costs per boe E&P LOE 41.4 E&P LOE 6.85 E&P GM&T 22.3 E&P GM&T 3.69 E&P Cash G&A 1 13.1 E&P Cash G&A1 2.17 Production Taxes 13.0 Production Taxes 2.16 Total E&P Operating Costs 89.8 Total Operating Costs 14.88 Adjusted E&P EBITDAX 159.2 Adjusted E&P EBITDAX per boe 26.39 Cash distributions from midstream ownership 33.1 Other adjustments 2 (4.1) OAS Adjusted EBITDAX 3 188.2 Balance Sheet 12/31/20 ($MM)6 unless otherwise noted OAS Unhedged Adjusted EBITDAX 108.0 Borrowing Base 575.0 4 OAS CapEx Borrowing under revolver 260.0 E&P CapEx 8.7 LCs 6.8 Midstream CapEx from retained DevCo ownership (1.2) Total Revolver Exposure 268.8 Total CapEx 7.4 Other Debt (9/30/20) 6.3 Pro forma interest 5 3.1 Total Debt 273.1 Free Cash Flow Cash 10.7 Hedged 177.7 Liquidity 318.9 Unhedged 97.5 Estimated Annual Interest 5 12.5

1) Excludes litigation contingency of $22.75MM and $26.3MM of restructuring related expenses Leverage (12/31/20 Net Debt to 3Q20 Annualized OAS Adjusted EBITDAX) 2) In accordance with OAS credit facility to capture cash flows not associated with OMP Hedged 0.4x 3) OAS adjusted EBITDAX conforms to definition of EBITDAX in OAS credit facility and excludes OMP EBITDA 4) Excludes capitalized interest. Midstream CapEx reflects adjustments to prior reporting periods Unhedged 0.6x 5) Assumes interest based on Exit Revolver Exposure for entire period 6) 12/31/2020 figures reflect unaudited estimates of Oasis’s debt and cash balance as of that date and may differ from the cash and cash equivalents and long-term debt balances in the Company’s audited financial statements prepared in accordance with GAAP A New Tomorrow, Today Nasdaq: OAS 20 Reconciliation from Consolidated Financial Statements to E&P Business Adjusting for midstream benefits and credits $MM except per unit

2Q20 3Q20 Consolidated($) Adjustment1 ($) E&P($) Consolidated($) Adjustment1($) E&P($) Revenue 12.8 (5.6) 7.1 24.5 (9.7) 14.8 Gas Revenue Price per MCF 1.32 (0.58) 0.74 2.04 (0.81) 1.23 LOE 29.6 8.4 38.0 29.4 12.0 41.4 Lease Operating Expense LOE per Boe 6.01 1.71 7.72 4.87 1.99 6.85 Gathering, Marketing, and GM&T 23.8 1.8 25.5 20.3 2.0 22.3 Transport GM&T per Boe 4.83 0.36 5.19 3.37 0.33 3.69 Cash G&A 28.8 (8.4) 20.4 39.4 (26.3) 13.1 E&P Cash G&A Cash G&A per Boe 4.77 (1.39) 3.38 6.54 (4.37) 2.17 Per Unit($) Per Unit($) NYMEX WTI ($/Bbl) 27.35 40.96 Realized Oil Price 24.45 38.52 Oil Differential per Bbl 2.90 2.44 NYMEX Henry Hub ($/mmBtu) 1.75 1.99 Differentials Realized Gas Price per Mcf 0.74 1.23 Gas Differential per Mcf 1.01 0.76 Total Differential 3.93 3.15 GM&T 5.19 3.69 Differential + GMT 9.12 6.84 $MM($) Oasis Consolidated EBITDAX 186.7 Less: OMP DevCo EBITDAX 57.9 EBITDAX Reconciliation to OAS Add: EBITDAX Attributable to OAS 19.8 credit agreement Add: Cash Distributions from OMP to OAS 13.3 Add: Adjustment (1) 26.3 EBITDAX per OAS credit agreement 188.2

1) Adjustment to Gas Revenue, LOE, GM&T are related to midstream credits for consolidating purposes. G&A and EBITDAX adjustments are related to restructuring costs incurred in 2Q20 and 3Q20. Note that G&A does not include litigation contingency of $22.75MM accrued in 3Q20

A New Tomorrow, Today Nasdaq: OAS 21 Oasis and OMP Financial Highlights1,2

OAS & OMP Leverage ($MM) OMP Financial Highlights – 3Q20 Actuals ($MM)

OAS OMP Bighorn Bobcat Beartooth Panther Total

Revolving credit facility Gross Operating Income $16.7 $22.5 $6.5 $1.7 $47.4 Capacity $575.0 $575.0 Gross Depreciation & $3.5 $4.1 $2.3 $0.6 $10.5 Outstanding Borrowings 260.0 $487.5 Impairment Surety bonds 2.3 $2.5 Gross Midstream EBITDA $20.2 $26.6 $ 8.8 $2.3 $57.9 Letters of credit 6.8 $0.0 OMP Ownership 100% 35% 70% 100% Finance lease liabilities 4.1 $0.3 Net OMP EBITDA $20.2 $9.5 $6.2 $2.3 $38.2 Total debt 273.1 $490.3 less: Cash PubCo Expenses $0.9 Cash 10.7 $34.7 Net OMP EBITDA (net of PubCo expenses) $37.3 Net Debt $262.4 $455.6 less: Cash interest $2.5 3Q20 EBITDAX (OAS is unhedged) $108.0 $37.3 less: Maintenance CapEx $0.8 Leverage (Net Debt to Annualized EBITDAX) 0.6x 3.05x Distributable Cash Flow $34.1 Declared Distribution LP $18.3 GP $1.0 Total Declared Distribution $19.3 Coverage 1.8x Guided Coverage for 3Q20 ~1.6-1.7x

1) Debt is calculated in accordance with respective credit facility definitions. OAS and OMP debt are not cross collateralized and guarantors under OAS credit facility are not responsible for OMP debt. OAS revolver, cash, and LCs, are as of 12/31/20 and surety bonds and finance lease liabilities are as of 9/30/20. OMP net debt as of 9/30/20 2) 12/31/2020 figures reflect unaudited estimates of Oasis’s debt and cash balance as of that date and may differ from the cash and cash equivalents and long-term debt balances in the Company’s audited financial statements prepared in accordance with GAAP

A New Tomorrow, Today Nasdaq: OAS 22 Contact Information

Oasis 1001 Fannin Street, Suite 1500 Houston, Texas, 77002 Main: (281) 404-9500 Owner Relations (Toll Free): (855) 209-8370 Investor Relations: Douglas E. Brooks (CEO) Michael Lou (CFO) Bob Bakanauskas (Director, IR) (281) 404-9600 www.OasisPetroleum.com

A New Tomorrow, Today 23 Nasdaq: OAS