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                                                                     Exhibit 2.2
                                 FIRST AMENDMENT
                                       TO
                          AGREEMENT AND PLAN OF MERGER


         FIRST AMENDMENT TO AGREEMENT AND PLAN OF MERGER, dated May 12, 1998
(this "Amendment"), to the Agreement and Plan of Merger, dated as of May 12,
1998, by and among Lomak Petroleum, Inc., a Delaware corporation ("Lomak"),
Domain Energy Corporation, a Delaware corporation (the "Company"), and DEC
Acquisition, Inc., a Delaware corporation ("Merger Sub").

                                   WITNESSETH:

         WHEREAS, Lomak, the Company and Merger Sub are parties to an Agreement
and Plan of Merger, dated as of May 12, 1998 (the "Original Merger Agreement"),
providing for the merger of Merger Sub with and into the Company on the terms
and conditions set forth therein; and

         WHEREAS, Lomak, the Company and Merger Sub desire to amend the Original
Merger Agreement.

         NOW, THEREFORE, in consideration of the premises and the
representations, warranties, covenants and agreements herein contained and other
valuable consideration, the receipt and adequacy whereof are hereby
acknowledged, the parties hereto hereby, intending to be legally bound,
represent, warrant, covenant and agree as follows:

         1. Capitalized terms used and not defined herein shall have the meaning
given to such terms in the Original Merger Agreement.

         2. The Company hereby represents and warrants to Lomak and Merger Sub
as follows, which representations and warranties shall be deemed to form part of
the representations and warranties of the Company included in Article IV of the
Original Merger Agreement for all purposes of the Original Merger Agreement:

                  (a) First Reserve Fund VII, Limited Partnership (the
"Principal Stockholder") is the record owner of 7,820,718 shares of Company
Common Stock;

                  (b) on the date hereof, 7,553,860 votes constituted a majority
of the outstanding voting power of Company Common Stock; and

                  (c) on the date hereof, the Principal Stockholder has
delivered a written consent to the Company approving and adopting the Original
Merger Agreement in accordance with applicable law, including without limitation
the DGCL, and such consent will, upon mailing by the Company of the notice as
described in Section 3 below, constitute the Company Stockholder Approval and no
other approvals of the stockholders of the Company other than such consent are
required to effect the Merger.


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         3. The Company will, promptly after the execution of this Amendment,
mail, in accordance with Section 228(d) of the DGCL, notice of the corporation
action without a meeting taken by the Principal Stockholder to those Company
stockholders who have not consented to such action in writing and who, if the
action had been taken at a meeting of Company stockholders, would have been
entitled to notice of the meeting if the record date for such meeting had been
the date that written consents signed by a sufficient number of holders to take
such action were delivered to the Company in accordance with Section 228(c) of
the DGCL. The covenant of the Company in this Section 3 shall be deemed to form
part of the covenants of the Company included in Article VII of the Original
Merger Agreement for all purposes of the Original Merger Agreement.

         4. All references to "Proxy Statement/Prospectus" in the Original
Merger Agreement shall be deemed in all cases in the Original Merger Agreement
to include the information statement required to be sent to the Company's
stockholders pursuant to Section 14(c) of the Exchange Act in connection with
the Principal Stockholder's consent described in this Amendment.

         5. Notwithstanding anything contained in the Original Merger Agreement
to the contrary, including without limitation Section 7.13 thereof, the Company
shall not be required to hold the Company Special Meeting.

         6. This Amendment shall constitute an Ancillary Agreement for all
purposes of the Original Merger Agreement.

         7. The validity, interpretation, construction and performance of this
Amendment shall be governed by, and construed in accordance with, the laws of
Delaware without reference to rules relating to conflicts of laws.

         8. This Amendment may be executed in one or more counterparts, all of
which shall be considered one and the same agreement, and shall become effective
when one or more counterparts have been signed by each of the parties and
delivered to each party.

         9. Except as expressly modified and amended by this Amendment, the
Original Merger Agreement shall continue in full force and effect and is hereby
ratified and confirmed in all respects.

                  [Remainder of page intentionally left blank.]

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         IN WITNESS WHEREOF, Lomak, the Company and Merger Sub have duly
executed this Amendment on the date first above written.

                                   LOMAK PETROLEUM, INC.


                                By:
                                   --------------------------------------------
                                   John H. Pinkerton
                                   President and Chief Executive Officer


                                   DEC ACQUISITION, INC.


                                By:
                                   --------------------------------------------
                                    John H. Pinkerton
                                    President


                                   DOMAIN ENERGY CORPORATION


                                By:
                                   --------------------------------------------
                                   Michael V. Ronca
                                   President and Chief Executive Officer

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