**
**Exhibit 2.2**

WARRANT ASSIGNMENT AND ASSUMPTION AGREEMENT 

HAMMERHEAD ENERGY INC., 

DECARBONIZATION PLUS ACQUISITION CORPORATION IV, 

CONTINENTAL STOCK TRANSFER & TRUST COMPANY, 

COMPUTERSHARE INC. 

and 

COMPUTERSHARE TRUST COMPANY, N.A. 

Dated February 21, 2023 

This Assignment and Assumption Agreement (the “***Agreement***”) is entered into as of February 21, 2023 (the“***Effective Date***”), by and among Decarbonization Plus Acquisition IV Corporation, an Alberta corporation (“***DCRD***”), Hammerhead Energy Inc., an Alberta corporation (“***NewCo***”),Continental Stock Transfer & Trust Company, a New York corporation (“***Continental***”) and Computershare Inc., a Delaware corporation, and its affiliate, Computershare Trust Company, N.A., a federally chartered trustcompany (collectively, “***Computershare***”). Capitalized terms used but not otherwise defined herein shall have the meanings given to such terms in the Business Combination Agreement (as defined below). 

WHEREAS, DCRD and Continental have previously entered into the SPAC Warrant Agreement governing the terms of the SPAC Warrants; 

WHEREAS, DCRD previously transferred by way of continuation from the Cayman Islands to Alberta in accordance with the Cayman Islands CompaniesAct (as amended) and domesticated as an Alberta corporation in accordance with the applicable provisions of the Business Corporations Act (Alberta); 

WHEREAS, pursuant to the Business Combination Agreement, dated as of September 25, 2022 (as may be amended from time to time, the“***Business Combination Agreement***”), by and among DCRD, Hammerhead Resources Inc., an Alberta corporation, NewCo, and 2453729 Alberta ULC, an Alberta unlimited liability corporation, the parties intend to consummate a businesscombination, pursuant to which, among other things, DCRD will amalgamate with NewCo on or about the date hereof (the “***SPAC Amalgamation***”) and form one corporate entity (”***New SPAC***”); 

WHEREAS, in connection with the SPAC Amalgamation and pursuant to the Business Combination Agreement, each SPAC Warrant, including (a)15,812,000 warrants sold to the public in DCRD’s initial public offering (the “***DCRD IPO***” and such warrants, the “***DCRD Public Warrants***”) and (b) 12,737,500 warrants issued to Decarbonization PlusAcquisition Sponsor IV LLC, a Cayman Islands limited liability company (“***DCRD Sponsor***”), and certain of DCRD’s independent directors in connection with the DCRD IPO (the “***DCRD Private PlacementWarrants***”), will be exchanged for warrants to purchase an equal number of Class A common 
**

shares in the authorized share capital of New SPAC (“***New SPAC Class************ A Common Shares***”) (as exchanged, such DCRD Public Warrants beingreferred to as “***Public Warrants***,” such DCRD Private Placement Warrants being referred to as “***Private Placement Warrants***” and such SPAC Warrants being referred to as “***Warrants***”)and be governed by the Amended and Restated Warrant Agreement to be entered into on or about the date hereof by New SPAC and Computershare (the “***Amended and Restated Warrant Agreement***”); 

WHEREAS, in connection with the foregoing, DCRD, NewCo, Continental and Computershare wish that (i) New SPAC shall assume by way ofassignment and assumption all of the liabilities, duties and obligations of DCRD under and in respect of the SPAC Warrant Agreement, (ii) Computershare shall be appointed as successor warrant agent under the SPAC Warrant Agreement and(iii) DCRD and the Continental shall be released from all liabilities, duties and obligations under and in respect of the SPAC Warrant Agreement; and 

WHEREAS, Continental consents to the assignment and assumption of the SPAC Warrant Agreement from DCRD to New SPAC and wishes to release DCRDfrom its liabilities, duties and obligations under and in respect of the SPAC Warrant Agreement and DCRD consents to the assignment and assumption of the SPAC Warrant Agreement from Continental to Computershare and wishes to release Continental fromits liabilities, duties and obligations under and in respect of the SPAC Warrant Agreement. 

NOW, THEREFORE, the parties hereby agree as follows: 

 
1.
Assignment and Assumption. In accordance with Section 8.2 and Section 9.1 of the WarrantAgreement: 

 
 (a)
New SPAC shall be substituted for DCRD in the SPAC Warrant Agreement and shall become obligated to perform allof the liabilities, duties and obligations of DCRD under and in respect of the SPAC Warrant Agreement. New SPAC shall undertake full performance of the SPAC Warrant Agreement in the place of DCRD and shall faithfully and fully perform the SPACWarrant Agreement as if New SPAC had been the original party thereto. 

 
 (b)
Computershare shall be substituted for Continental in the SPAC Warrant Agreement and shall be vested with thesame powers, rights, liabilities, duties, obligations and responsibilities as if it had been originally named as warrant agent under the SPAC Warrant Agreement; provided that, in no event shall Computershare be liable for the actions or omissions ofContinental under the SPAC Warrant Agreement prior to this assignment and assumption. Computershare undertakes full performance of the SPAC Warrant Agreement in the place of Continental. In furtherance of the foregoing, DCRD hereby waives therequirement in Section 8.2.1 of the SPAC Warrant Agreement that the successor warrant agent be a New York corporation with its principal office in the Borough of Manhattan, City and State of New York. 

 
 (c)
Continental and DCRD shall be irrevocably and unconditionally released from their liabilities, duties andobligations under and in respect of the SPAC Warrant Agreement, and their respective rights against each other under and in respect of the SPAC Warrant Agreement shall be cancelled. 

 
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 (d)
New SPAC shall owe to Computershare all the rights that were, immediately prior to the assignment andassumption, owed to Continental under and in respect of the SPAC Warrant Agreement. 

 
 (e)
Computershare shall perform and discharge all liabilities, duties and obligations under and in respect of theSPAC Warrant Agreement and be bound by its terms in every way as if New SPAC had been the original party thereto in place of DCRD. 

 
 (f)
New SPAC shall perform and discharge all liabilities, duties and obligations under and in respect of the SPACWarrant Agreement and be bound by its terms in every way as if Computershare had been the original party thereto in place of Continental. 

 
2.
Amendment and Restatement of Warrant Agreement. At the effective time of the SPAC Amalgamation, pursuantto Section 9.8 of the SPAC Warrant Agreement, New SPAC and Computershare shall enter into the Amended and Restated Warrant Agreement to reflect that, effective upon consummation of the SPAC Amalgamation, each Public Warrant and PrivatePlacement Warrant will entitle the holder to purchase New SPAC Class A Common Shares in accordance with the terms and subject to the conditions set forth in the Amended and Restated Warrant Agreement. 

 
3.
Release of DCRN and Continental from Liabilities. In consideration of this assignment and assumption,DCRD and Continental shall be released and discharged of all liabilities, duties and obligations to perform under the SPAC Warrant Agreement as of the date hereof, and shall be fully relieved of all liability to New SPAC or Computershare arising outof the SPAC Warrant Agreement. 

 
4.
Effectiveness. This Agreement shall be effective as of the Effective Date. 

 
5.
Governing Law. This Agreement shall be governed by, and construed in accordance with, the laws of theState of New York, as such laws are applied to contracts entered into and performed in such State without resort to that State’s conflict-of-laws rules.

 
6.
Counterparts. This Agreement may be executed in counterparts, each of which shall be deemed to be anoriginal, but all of which together shall constitute one and the same instrument. Execution and delivery of this Agreement by email or exchange of facsimile copies bearing the facsimile signature of a party hereto shall constitute a valid andbinding execution and delivery of this Agreement by such party. 

 
7.
Successors and Assigns. All the covenants and provisions of this Agreement shall bind and inure to thebenefit of each party’s respective successors and assigns. 

[*Signature Page Follows*] 

 
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IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed as ofthe date first above written. 

 
**DECARBONIZATION PLUS ACQUISITION IV CORPORATION**By: /s/ Peter HaskopoulosName: Peter HaskopoulosTitle: Chief Financial Officer, Chief Accounting Officer and Secretary
 

 
SIGNATUREPAGETO

ASSIGNMENTAND ASSUMPTION AGREEMENT

**CONTINENTAL STOCK TRANSFER & TRUST COMPANY**By: /s/ Steven VacanteName: Steven VacanteTitle: Vice President
 

 
SIGNATURE PAGETO

ASSIGNMENTAND ASSUMPTION AGREEMENT

**HAMMERHEAD ENERGY INC.**By: /s/ Michael KohutName: Michael KohutTitle: Senior Vice President and Chief Financial Officer
 

 
SIGNATURE PAGETO

ASSIGNMENTAND ASSUMPTION AGREEMENT

**COMPUTERSHARE INC.**

**COMPUTERSHARE TRUST COMPANY, N.A., as Warrant Agent**
By: /s/ Collin EkeoguName: Collin EkeoguTitle: Manager, Corporate Actions
 

 
SIGNATURE PAGE

TOASSIGNMENTAND ASSUMPTION AGREEMENT