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                                                                    EXHIBIT 5.1


                     [PORTER & HEDGES, L.L.P. LETTERHEAD]



                                  June 6, 1997




DI Industries, Inc.
10370 Richmond Avenue, Suite 600
Houston, Texas 77042-4136

     Re: Opinion as to legality of Senior Notes due 2007

Ladies & Gentlemen:

     We have examined the articles of incorporation, the bylaws, and the
corporate proceedings of DI Industries, Inc., a Texas corporation (the
"Company"), and certain of its subsidiaries relating to the registration under
the Securities Act of 1933, as amended, of $125,000,000 aggregate principal
amount of Senior Notes due 2007 (the "Notes") (including guarantees by certain
of the Company's domestic subsidiaries (the "Guarantees")), to be issued
pursuant to an Indenture between the Company and Texas Commerce Bank National
Association, as Trustee (the "Indenture"), and the qualification of the
Indenture under the Trust Indenture Act of 1939, as amended, on behalf of the
Company, for the purpose of sale of the Notes to the underwriters for offering
to the public. In giving this opinion, we have made such other examinations as
we deem necessary in the premises and from such examinations we are of the
opinion that:

     1.   Upon execution and delivery, the Indenture will have been duly
          authorized by all necessary corporate action, and it will constitute
          a legal, valid, and binding instrument enforceable in accordance with
          its terms, except as enforcement may be limited by bankruptcy,
          insolvency, or other laws relating to or affecting enforcement of
          creditors' rights generally, and except that remedies of specific
          performance and other forms of equitable relief are subject to
          certain equitable defenses and to the discretion of the court.



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DI Industries, Inc.
June 6, 1997
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          2.   When issued and sold, the Notes and the Guarantees will have 
               been duly authorized by all necessary corporate action, and when
               authenticated, delivered to and paid for by the underwriters,
               will be legal, valid, and binding obligations of the Company and
               the affected subsidiaries, respectively, entitled to the
               benefits of the Indenture and enforceable in accordance with its
               and their terms, except as enforcement may be limited by
               bankruptcy, insolvency or other laws relating to or affecting
               enforcement of creditors' rights generally, and except that
               remedies of specific performance and other forms of equitable
               relief are subject to certain equitable defenses and to the
               discretion of the court.

         We consent to the use of this opinion as an exhibit to the
Registration Statement and to the reference to our firm under the caption
"Legal Matters" in the Prospectus included as a part of the Registration
Statement.

         This opinion is conditioned upon the Registration Statement being
declared effective and upon compliance by the Company with all applicable
provisions of the Securities Act of 1933, as amended, and such state securities
rules, regulations and laws as may be applicable.


                                                Very truly yours,


                                                /s/ PORTER & HEDGES, L.L.P.

                                                PORTER & HEDGES, L.L.P.