|        |
|--------|
|        |  |
| ý | Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 |

|        |
|--------|
|        |  |
|   | Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 |

|                         |
|-------------------------|
|                         |  |  |
| Delaware                |   | 72-1440714 |
| State of incorporation: |   | I.R.S. Employer Identification No. |

|                                         |
|-----------------------------------------|
|                                         |  |  |
| Title of each class                     |   | Name of each exchange on which registered |
| Common Stock, par value $.001 per share |   | New York Stock Exchange |

|                                   |
|-----------------------------------|
|                                   |  |  |  |  |  |  |
| Large accelerated filer | ¬¬ |   |    | Accelerated filer |   | ¬ |
| Non-accelerated filer             | ¬ | (Do not check if a smaller reporting company) |    | Smaller reporting company |   | x |
|                              |   |   |   | Emerging growth company |   | ¬ |

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|     |                         |
|-----|-------------------------|
| (a) | 1. FINANCIAL STATEMENTS |

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|        |
|--------|
|        |  |  |  |
|   |   |   |
| ** 2.1 |  |   | Plan and Agreement of Merger by and among Optima Petroleum Corporation, Optima Energy (U.S.) Corporation, its wholly-owned subsidiary, and Goodson Exploration Company, NAB Financial L.L.C., Dexco Energy, Inc., American Explorer, L.L.C. (incorporated herein by reference to Appendix G of the Proxy Statement on Schedule 14A filed July 22, 1998). |
|   |   |
| ** 2.2 |  |   | Purchase and Sale Agreement dated as of June 19, 2013, between PetroQuest Energy, L.L.C. and Hall-Houston Exploration II, L.P. (incorporated herein by reference to Exhibit 2.1 to Form 8-K filed on June 20, 2013). |
|   |   |   |
| ** 2.3 |  |   | Purchase and Sale Agreement dated as of June 19, 2013, between PetroQuest Energy, L.L.C. and Hall-Houston Exploration III, L.P. (incorporated herein by reference to Exhibit 2.2 to Form 8-K filed on June 20, 2013). |
|   |   |   |
| ** 2.4 |  |   | Purchase and Sale Agreement dated as of June 19, 2013, between PetroQuest Energy, L.L.C. and Hall-Houston Exploration IV, L.P. (incorporated herein by reference to Exhibit 2.3 to Form 8-K filed on June 20, 2013). |
|   |   |   |
| ** 2.5 |  |   | Purchase and Sale Agreement dated as of June 19, 2013, between PetroQuest Energy, L.L.C. and GOM-H Exploration, LLC (incorporated herein by reference to Exhibit 2.4 to Form 8-K filed on June 20, 2013). |
|   |   |   |
| **#2.6 |  |   | Purchase and Sale Agreement dated as of June 4, 2015, by and between PetroQuest Energy, L.L.C. and WSGP Gas Producing, LLC (incorporated herein by reference to Exhibit 2.1 to Form 10-Q filed on August 5, 2015). |
|   |   |   |
| **#2.7 |  |   | Purchase and Sale Agreement dated as of April 20, 2016, by and between PetroQuest Energy, L.L.C. and GR Woodford Properties, LLC (incorporated herein by reference to Exhibit 2.1 to Form 10-Q filed on August 3, 2016). |
|   |   |   |
| 3.1    |  |    | Certificate of Incorporation of PetroQuest Energy, Inc. (incorporated herein by reference to Exhibit 4.1 to Form 8-K filed September 16, 1998). |
|   |   |
| 3.2    |  |    | Certificate of Domestication of Optima Petroleum Corporation (incorporated herein by reference to Exhibit 4.4 to Form 8-K filed September 16, 1998). |
|   |   |
| 3.3    |  |    | Certificate of Designations, Preferences, Limitations and Relative Rights of The Series a Junior Participating Preferred Stock of PetroQuest Energy, Inc. (incorporated herein by reference to Exhibit A of the Rights Agreement attached as Exhibit 1 to Form 8-A filed November 9, 2001). |

|        |
|--------|
|        |  |  |  |
| 3.4    |  |    | Certificate of Designations establishing the 6.875% Series B Cumulative Convertible Perpetual Preferred Stock, dated September 24, 2007 (incorporated herein by reference to Exhibit 3.1 to Form 8-K filed on September 24, 2007). |
|   |   |
| 3.5    |  |    | Certificate of Amendment to Certificate of Incorporation dated May 14, 2008 (incorporated herein by reference to Exhibit 3.1 to Form 8-K filed June 23, 2009). |
|   |   |
| 3.6    |  |   | Certificate of Amendment to Certificate of Incorporation dated May 18, 2016 (incorporated herein by reference to Exhibit 3.1 to Form 8-K filed on May 20, 2016). |
|   |   |   |
| 3.7    |  |   | Certificate of Amendment to Certificate of Incorporation dated May 18, 2016 (incorporated herein by reference to Exhibit 3.2 to From 8-K filed on May 20, 2016). |
|   |   |   |
| 3.8    |  |    | Bylaws of PetroQuest Energy, Inc., as amended of February 19, 2016 (incorporated herein by reference to Exhibit 3.1 to Form 8-K filed February 22, 2016). |
|   |   |
| 4.1    |  |    | Indenture, dated August 19, 2010, between PetroQuest Energy, Inc. and The Bank of New York Mellon Trust Company, N.A. (incorporated herein by reference to Exhibit 4.2 to Form 8-K filed on August 19, 2010). |

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|             |
|-------------|
|             |  |  |  |
|        |   |
| 4.2         |  |    | First Supplemental Indenture, dated August 19, 2010, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and The Bank of New York Mellon Trust Company, N.A. (incorporated herein by reference to Exhibit 4.3 to Form 8-K filed on August 19, 2010). |
|        |   |
| 4.3         |  |   | Second Supplemental Indenture, dated July 3, 2013, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and The Bank of New York Mellon Trust Company, N.A. (incorporated herein by reference to Exhibit 4.2 to Form 8-K filed on July 3, 2013). |
|        |   |   |
| 4.4         |  |   | Third Supplemental Indenture, dated October 23, 2013, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and The Bank of New York Mellon Trust Company, N.A.(incorporated herein by reference to Exhibit 4.7 to Form 10-K filed on March 6, 2015). |
|        |   |   |
| 4.5         |  |   | Fourth Supplemental Indenture, dated February 1, 2015, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and U.S. Bank National Association, as successor trustee to The Bank of New York Mellon Trust Company, N.A. (incorporated herein by reference to Exhibit 4.1 to Form 8-K filed on February 3, 2016). |
|        |   |   |
| 4.6         |  |   | Registration Rights Agreement, dated February 17, 2016, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and Seaport Global Securities LLC, as representative of the several investors named therein (incorporated herein by reference to Exhibit 4.2 to Form 8-K filed on February 18, 2016). |
|        |   |   |
| 4.7         |  |   | Indenture, dated February 17, 2016, between PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and Wilmington Trust, National Association (incorporated herein by reference to Exhibit 4.1 to Form 8-K filed on February 18, 2016). |
|        |   |   |
| 4.8         |  |   | First Supplemental Indenture, dated as of September 13, 2016, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and Wilmington Trust, National Association (incorporated herein by reference to Exhibit 4.1 to Form 8-K filed on September 14, 2016). |
|        |   |   |
| 4.9         |  |   | Registration Rights Agreement, dated July 3, 2013, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and J.P. Morgan Securities LLC, as representative of the several initial purchasers named therein (incorporated herein by reference to Exhibit 4.3 to Form 8-K filed on July 3, 2013). |
|        |   |   |
| 4.10        |  |   | Waiver of Registration Rights, dated as of September 13, 2016, among PetroQuest Energy, Inc., the Subsidiary Guarantors and Seaport Global Securities LLC (incorporated herein by reference to Exhibit 4.2 to Form 8-K filed on September 14, 2016). |
|        |   |   |
| 4.11        |  |   | Indenture, dated September 27, 2016, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, and Wilmington Trust, National Association (incorporated herein by reference to Exhibit 4.1 to Form 8-K filed on September 27, 2016). |
|        |   |   |
| 4.12        |  |   | Registration Rights Agreement, dated September 27, 2016, among PetroQuest Energy, Inc., the Subsidiary Guarantors identified therein, Jefferies LLC and Seaport Global Securities LLC (incorporated herein by reference to Exhibit 4.2 to Form 8-K filed on September 27, 2016). |
|        |   |   |
| †10.1 |  |    | PetroQuest Energy, Inc. 1998 Incentive Plan, as amended and restated effective May 14, 2008 (the “Incentive Plan”) (incorporated herein by reference to Appendix A of the Proxy Statement on Schedule 14A filed April 9, 2008). |
|        |   |
| †10.2 |  |    | Form of Incentive Stock Option Agreement for executive officers (including Charles T. Goodson, Arthur M. Mixon, III, J. Bond Clement and Edward E. Abels, Jr.) under the PetroQuest Energy, Inc. 1998 Incentive Plan (incorporated herein by reference to Exhibit 10.2 to Form 10-K filed February 27, 2009). |
|        |   |
| †10.3 |  |    | Form of Nonstatutory Stock Option Agreement under the PetroQuest Energy, Inc. 1998 Incentive Plan (incorporated herein by reference to Exhibit 10.3 to Form 10-K filed February 27, 2009). |
|        |   |

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|              |
|--------------|
|              |  |  |  |
| †10.4  |  |    | Form of Restricted Stock Agreement for executive officers (including Charles T. Goodson, Arthur M. Mixon, III, J. Bond Clement and Edward E. Abels, Jr.) under the PetroQuest Energy, Inc. 1998 Incentive Plan (incorporated herein by reference to Exhibit 10.4 to Form 10-K filed February 27, 2009). |
|         |   |
| †10.5  |  |    | PetroQuest Energy, Inc. Annual Incentive Plan (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed on May 13, 2010). |
|         |   |
| †10.6  |  |    | PetroQuest Energy, Inc. Annual Incentive Plan, as amended and restated (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed on June 8, 2010). |
|         |   |
| †10.7  |  |   | PetroQuest Energy, Inc. 2012 Employee Stock Purchase Plan (incorporated herein by reference to Appendix A to Schedule 14A filed March 28, 2012). |
|         |   |   |
| †10.8  |  |   | PetroQuest Energy, Inc. Long-Term Cash Incentive Plan (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed November 15, 2012). |
|         |   |   |
| †10.9  |  |   | PetroQuest Energy, Inc. 2013 Incentive Plan (incorporated herein by reference to Appendix A to the Company’s Definitive Proxy Statement on Schedule 14A filed on April 9, 2013). |
|         |   |   |
| †10.10 |  |   | Form of Award Notice of Restricted Stock Units - Employees (including Charles T. Goodson, Arthur M. Mixon, III, J. Bond Clement and Edward E. Abels, Jr.) under the PetroQuest Energy, Inc. Long-Term Cash Incentive Plan (incorporated herein by reference to Exhibit 10.2 to Form 8-K filed November 15, 2012). |
|         |   |   |
| †10.11 |  |   | Form of Award Notice of Restricted Stock Units - Outside Director/Consultant under the PetroQuest Energy, Inc. Long-Term Cash Incentive Plan (incorporated herein by reference to Exhibit 10.3 to Form 8-K filed November 15, 2012). |
|         |   |   |
| †10.12 |  |   | Form of Restricted Stock Agreement - Executive Officers (including Charles T. Goodson, Arthur M. Mixon, III, J. Bond Clement and Edward E. Abels, Jr.) under the PetroQuest Energy, Inc. 1998 Incentive Plan (incorporated herein by reference to Exhibit 10.4 to Form 8-K filed November 15, 2012). |
|         |   |   |
| †10.13 |  |   | Form of Restricted Stock Units Agreement - Employees (including Charles T. Goodson, Arthur M. Mixon, III, J. Bond Clement and Edward E. Abels, Jr.) under the PetroQuest Energy, Inc. 2013 Incentive Plan (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed November 19, 2014). |
|         |   |   |
| †10.14 |  |   | Form of Award Notice of Phantom Stock Units - Employees (including Charles T. Goodson, Arthur M. Mixon, III, J. Bond Clement and Edward E. Abels, Jr.) under the PetroQuest Energy, Inc. Long-Term Cash Incentive Plan (incorporated herein by reference to Exhibit 10.2 to Form 8-K filed November 19, 2014). |
|         |   |   |
| †10.15 |  |   | Form of Performance Unit Notice and Award- Employees (including Charles T. Goodson, Arthur M. Mixon, III, J. Bond Clement and Edward E. Abels, Jr.) under the PetroQuest Energy, Inc. Long-Term Cash Incentive Plan (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed November 21, 2014). |
|         |   |   |
| †10.16 |  |    | Amended Executive Employment Agreement dated effective as of December 31, 2008, between Charles T. Goodson and PetroQuest Energy, Inc. (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed January 6, 2009). |
|         |   |
| †10.17 |  |    | Amended Executive Employment Agreement dated effective as of December 31, 2008, between Arthur M. Mixon, III and PetroQuest Energy, Inc. (incorporated herein by reference to Exhibit 10.3 to Form 8-K filed January 6, 2009). |

|              |
|--------------|
|              |  |  |  |
| †10.18 |  |    | Amended Executive Employment Agreement dated effective as of December 31, 2008, between J. Bond Clement and PetroQuest Energy, Inc. (incorporated herein by reference to Exhibit 10.21 to Form 10-K filed February 27, 2009). |
|         |   |

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|              |
|--------------|
|              |  |  |  |
| †10.19 |  |   | Executive Employment Agreement dated February 1, 2014 between PetroQuest Energy, Inc. and Edward E. Abels, Jr. (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed February 5, 2014). |
|         |   |   |
| †10.20 |  |    | Form of Amended Termination Agreement between the Company and each of its executive officers, including Charles T. Goodson, Arthur M. Mixon, III, and J. Bond Clement (incorporated herein by reference to Exhibit 10.6 to Form 8-K filed January 6, 2009). |
|         |   |   |
| †10.21 |  |   | Termination Agreement dated February 1, 2014 between PetroQuest Energy, Inc. and Edward E. Abels, Jr. (incorporated herein by reference to Exhibit 10.2 to Form 8-K filed February 5, 2014). |
|         |   |   |
| †10.22 |  |    | Form of Indemnification Agreement between PetroQuest Energy, Inc. and each of its directors and executive officers, including Charles T. Goodson, Arthur M. Mixon, III, , J. Bond Clement, Edward E. Abels, Jr., William W. Rucks, IV, E. Wayne Nordberg, J. Gerard Jolly, W.J. Gordon, III and Charles F. Mitchell, II (incorporated herein by reference to Exhibit 10.21 to Form 10-K filed March 13, 2002). |
|         |   |
| †10.23 |  |    | Form of Surrender and Cancellation Agreement for Directors and Executive Officers (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed on September 16, 2010). |
|         |   |
| †10.24 |  |   | PetroQuest Energy, Inc. 2016 Long Term Incentive Plan (incorporated herein by reference to Appendix A to the Company's Definitive Proxy Statement on Schedule 14A filed on April 7, 2016). |
|         |   |   |
| 10.25        |  |   | Collateral Trust Agreement, dated February 17, 2016, among PetroQuest Energy, Inc., the guarantors from time to time party thereto, Wilmington Trust, National Association, as Trustee, the other Parity Lien Debt Representatives from time to time party thereto and Wilmington Trust, National Association, as Collateral Trustee (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed on February 18, 2016). |
|         |   |   |
| 10.26        |  |   | Intercreditor Agreement, dated February 17, 2016, by and between JPMorgan Chase Bank, N.A., as Priority Lien Agent, and Wilmington Trust, National Association, as Second Lien Collateral Trustee (incorporated herein by reference to Exhibit 10.2 to Form 8-K filed on February 18, 2016). |
|         |   |   |
| 10.27        |  |   | Multidraw Term Loan Agreement, dated as of October 17, 2016, among PetroQuest Energy, Inc., PetroQuest Energy, L.L.C., Franklin Custodian Funds - Franklin Income Fund, and Wells Fargo Bank, National Association, as administrative agent (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed on October 17, 2016). |
|         |   |   |
| ## 10.28     |  |   | Lease Acquisition Agreement, effective as of December 18, 2017, between Navitas Oil & Gas, LLC and PetroQuest Energy, L.L.C. (incorporated herein by reference to Exhibit 10.28 to Form 10-K filed on March 8, 2018). |
|         |   |   |
| 14.1         |  |    | Code of Business Conduct and Ethics (incorporated herein by reference to Exhibit 14.1 to Form 10-K filed on March 8, 2018). |
|         |   |
| 21.1         |  |    | Subsidiaries of the Company (incorporated by reference to Exhibit 21.1 to Form 10-K filed on March 8, 2018). |
|         |   |
| 23.1         |  |    | Consent of Independent Registered Public Accounting Firm (incorporated herein by reference to Exhibit 23.1 to Form 10-K filed on March 8, 2018). |
|         |   |
| 23.2         |  |    | Consent of Ryder Scott Company, L.P. (incorporated herein by reference to Exhibit 23.2 to Form 10-K filed on March 8, 2018). |
|         |   |   |
| 31.1         |  |    | Certification of Chief Executive Officer pursuant to Rule 13-a-14(a) / Rule 15d-14(a), promulgated under the Securities Exchange Act of 1934, as amended (incorporated herein by reference to Exhibit 31.1 to Form 10-K filed on March 8, 2018). |
|         |   |   |
| 31.2         |  |    | Certification of Chief Financial Officer pursuant to Rule 13-a-14(a) / Rule 15d-14(a), promulgated under the Securities Exchange Act of 1934, as amended (incorporated herein by reference to Exhibit 31.2 to Form 10-K filed on March 8, 2018). |
|         |   |   |

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|        |
|--------|
|        |  |  |  |
| *31.3  |  |   | Certification of Chief Executive Officer pursuant to Rule 13-a-14(a) / Rule 15d-14(a), promulgated under the Securities Exchange Act of 1934, as amended. |
|   |   |   |
| *31.4  |  |   | Certification of Chief Financial Officer pursuant to Rule 13-a-14(a) / Rule 15d-14(a), promulgated under the Securities Exchange Act of 1934, as amended. |
|   |   |   |
| 32.1   |  |    | Certification pursuant to 18 U.S.C. Section 1350, as adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, of Chief Executive Officer (incorporated herein by reference to Exhibit 32.1 to Form 10-K filed on March 8, 2018). |
|   |   |   |
| 32.2   |  |    | Certification pursuant to 18 U.S.C. Section 1350, as adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, of Chief Financial Officer (incorporated herein by reference to Exhibit 32.2 to Form 10-K filed on March 8, 2018). |
|   |   |   |
| 99.1   |  |    | Reserve report letter as of December 31, 2017, as prepared by Ryder Scott Company, L.P. (incorporated herein by reference to Exhibit 99.1 to Form 10-K filed on March 8, 2018). |

|         |
|---------|
|         |  |  |
| 101.INS |    | XBRL Instance Document (incorporated herein by reference to Exhibit 101.INS to Form 10-K filed on March 8, 2018). |
|    |   |   |
| 101.SCH |   | XBRL Taxonomy Extension Schema Document (incorporated herein by reference to Exhibit 101.SCH to Form 10-K filed on March 8, 2018). |
|    |   |   |
| 101.CAL |   | XBRL Taxonomy Extension Calculation Linkbase Document (incorporated herein by reference to Exhibit 101.CAL to Form 10-K filed on March 8, 2018). |
|    |   |   |
| 101.DEF |   | XBRL Taxonomy Definitions Linkbase Document (incorporated herein by reference to Exhibit 101.DEF to Form 10-K filed on March 8, 2018). |
|    |   |   |
| 101.LAB |   | XBRL Taxonomy Extension Label Linkbase Document (incorporated herein by reference to Exhibit 101.LAB to Form 10-K filed on March 8, 2018). |
|    |   |   |
| 101.PRE |   | XBRL Taxonomy Extension Presentation Linkbase Document (incorporated herein by reference to Exhibit 101.PRE to Form 10-K filed on March 8, 2018). |

|    |
|----|
|    |  |
| *  | Filed herewith. |
| ** | The registrant agrees to furnish supplementally a copy of any omitted schedule to the Agreements to the SEC upon request. |

|         |
|---------|
|         |  |
| † | Management contract or compensatory plan or arrangement |
| #       | Confidential treatment has been granted for portions of this exhibit. Omissions are designated with brackets containing asterisks. As part of our confidential treatment request, a complete version of this exhibit was filed separately with the SEC. |
| ##      | Confidential treatment has been requested for portions of this exhibit. Omissions are designated with brackets containing asterisks. As part of our confidential treatment request, a complete version of this exhibit has been filed separately with th SEC. |

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|        |
|--------|
|        |  |  |  |
|   | PETROQUEST ENERGY, INC. |
|   |   |   |
|   | By: |   | /s/ J. Bond Clement |
|   |   |   | J. Bond Clement |
|   |   |   | Executive Vice President, Chief Financial Officer, Treasurer |