<PAGE>
 
                                                                    EXHIBIT 10.4

                SECOND AMENDMENT TO LOAN AND SECURITY AGREEMENT

     This Second Amendment to Loan and Security Agreement (the "Amendment") is
made and entered into as of June 1, 1992, by and between RED MAN PIPE & SUPPLY
CO., an Oklahoma corporation ("Borrower"), and BARCLAYS BUSINESS CREDIT, INC., a
Connecticut corporation ("Lender").

                            PRELIMINARY STATEMENTS:

     1.   Borrower and Lender entered into that certain Loan and Security
Agreement dated as of May 3, 1991, as amended by that certain First Amendment to
Loan and Security Agreement dated as of July 30, 1991, governing the terms of up
to $25,000,000 in revolving credit loans (as amended, the "Agreement").

     2.   Borrower has requested that the Agreement be amended to provide for a
term loan from Lender to Borrower.

     3.   To facilitate issuance of letters of credit for the account of
Borrower, Borrower has further requested that the Agreement be amended to
contemplate the issuance of letter of credit guaranties by Lender.

     4.   Borrower and Lender desire to amend the Agreement to make certain
other revisions more particularly described herein.

                                  AGREEMENTS:

     NOW, THEREFORE, in consideration of the agreements herein contained,
subject to the terms and conditions set forth herein, Borrower and Lender hereby
agree as follows, and agree that the amendments specified below shall be
effective from and after the date hereof and shall be incorporated into the
Agreement and shall supersede those provisions in the Agreement referenced as
follows:

     1.   DEFINITIONS.

          (a) Terms used herein and defined in the Agreement shall have the
     meanings set forth in the Agreement except as otherwise provided herein.

          (b) The definitions of "Applicable Rate", "Average Daily
     Availability", "Average Daily Loan Balance", "Borrowing Base", "Loans" and
     "Other Agreements" contained in Section 1.1 of the Agreement are hereby
     deleted, and in place thereof shall be the following:


                                      -1-
<PAGE>
 
               "Applicable Rate - the Annual Revolving Rate or the Annual Term
          Rate, as the context may require, and, for purposes of Sections 3.1(D)
          and (E) of this Agreement, shall include the Default Rate."

               "Average Daily Availability - the amount obtained by adding the
          difference between the Borrowing Base and the unpaid balance of
          Revolving Credit Loans owing by Borrower to Lender at the end of each
          day during the period in question and by dividing such sum by the
          number of days in such period."

               "Average Daily Loan Balance - the amount obtained by adding the
          unpaid balance of Revolving Credit Loans owing by Borrower to Lender
          at the end of each day for each day during the period in question and
          by dividing such sum by the number of days in such period."

               "Borrowing Base - as at any date of determination thereof, an
          amount equal to the lesser of:

               (a) the Commitment as of such date, minus the outstanding
          principal amount of the Term Loan as of such date; or

               (b) an amount up to:

                    (i)    ninety percent (90%) of the net amount (after
               deduction of such reserves as Lender deems proper and necessary
               in its sole discretion, including a reserve for sales tax
               payables) of Eligible Accounts outstanding at such date;

                    PLUS

                    (ii)   the lesser of (A) $6,000,000 or (B) sixty percent
               (60%) of the value (after deduction of such reserves as Lender
               deems proper and necessary in its sole discretion) of Eligible
               Inventory at such date consisting of tubular goods held for sale
               in the ordinary course of Borrower's business, calculated on the
               basis of the lower of cost or market;

                    PLUS

                    (iii)  the lesser of (A) the Supply Inventory Maximum in
               effect on such date or (B) the Supply Inventory Advance Rate in
               effect on


                                      -2-
<PAGE>
 
               such date multiplied by the value (after deduction of such
               reserves as Lender deems proper and necessary in its sole
               discretion) of Eligible Inventory at such date consisting of
               consumable supplies held for sale in the ordinary course of
               Borrower's business, calculated on the basis of the lower of cost
               or market;

                    MINUS (subtract from the sum of clauses (i), (ii) and (iii)
               above)

                    (iv)   an amount equal to the sum of (A) the face amount of
               all LC Guaranties and Letters of Credit issued by Lender or
               Affiliates of Lender and outstanding at such date and (B) any
               amounts which Lender may be obligated to pay in the future for
               the account of Borrower pursuant to this Agreement, the other
               Agreements or otherwise.

          For purposes hereof, the net amount of Eligible Accounts at any time
          shall be the face amount of such Eligible Accounts, less any and all
          returns, discounts (which may, at Lender's option, be calculated on
          shortest terms), credits, allowances or excise taxes of any nature at
          any time issued, owing, claimed by Account Debtors, granted,
          outstanding or payable in connection with such Accounts at such time."

              "Loans - all loans and advances made by Lender pursuant to this
          Agreement, including, without limitation, all Revolving Credit Loans
          and the Term Loan."

              "Other Agreements - any and all agreements, instruments and
          documents heretofore, now or hereafter executed by Borrower or
          delivered to Lender in respect to the transactions contemplated by
          this Agreement, including, without limitation, the Term Note, the
          Guaranty, the Mortgages and the Acknowledgments, as the same may be
          modified, supplemented, extended or amended from time to time."

          (c) The following definitions are hereby added to Section 1.1 of the
     Agreement:

              "Annual Revolving Rate - as defined in Section 3.1(A) of this
          Agreement."


                                      -3-
<PAGE>
 
              "Annual Term Rate - as defined in Section 3.1(A) of this
          Agreement."

              "LC Guaranty - a guaranty executed by Lender at Borrower's
          request and in Lender's sole discretion in favor of a Person who has
          issued a Letter of Credit."

              "Letter of Credit - a letter of credit at any time issued for the
          account of Borrower.

              "Loan Documents - this Agreement and the Other Agreements."

              "Mortgages - the mortgages and/or deeds of trust to be executed
          by Borrower on or about a Term Loan Closing Date in favor of Lender
          and by which Borrower shall grant and convey to Lender, as security
          for the obligations, Liens upon the Real Property."

              "Real Property - those certain parcels of real Property to be
          purchased by Borrower from Superior Supply Company, and more
          particularly described on Exhibit "L" attached hereto."

              "Revolving Credit Loans - a Loan made by Lender as provided in
          Section 2.1(A) of this Agreement."

              "Term Loan - the Loan described in Section 2.1(B) of this
          Agreement."

              "Term Loan Closing Date - each date on which all of the
          conditions precedent to an advance under the Term Loan are satisfied
          and an advance under the Term Loan is made.

              "Term Note - the term note to be executed by Borrower on or about
          the first Term Loan Closing Date in favor of Lender to evidence the
          Term Loan, which shall be in the form of Exhibit "K" attached hereto."

     2.   THE LOANS. Section 2.1 of the Agreement is hereby deleted, and in
place thereof shall be the following:

          "2.1.  THE LOANS AND LC GUARANTIES.

                 (A) Provided that no Default or Event of Default has occurred,
                 Lender will make Revolving Credit Loans to Borrower from time
                 to time, in amounts as requested by Borrower, up to a maximum


                                      -4-
<PAGE>
 
          principal amount at any time outstanding equal to the Borrowing Base
          at such time. It is expressly understood and agreed that Lender may
          use the Borrowing Base as a maximum ceiling on Revolving Credit Loans
          outstanding to Borrower at any time. If the unpaid balance of the
          Revolving Credit Loans should exceed the Borrowing Base or any other
          limitation set forth in this Agreement, such Revolving Credit Loans
          shall nevertheless constitute obligations that are secured by the
          Collateral and entitled to all benefits thereof. Insofar as Borrower
          may request and Lender may be willing in its discretion to make
          Revolving Credit Loans to Borrower at a time when the unpaid balance
          of Revolving Credit Loans exceeds, or would exceed with the making of
          any such Revolving Credit Loan, the Borrowing Base (any such Revolving
          Credit Loan or Loans being herein referred to individually as an
          "Overadvance" and collectively as "Overadvances", Lender shall enter
          such Overadvances as debits in the Loan Account. All Overadvances
          shall be repaid ON DEMAND. In consideration of Lender making any
          Overadvance to Borrower, Borrower agrees to pay to Lender,
          contemporaneously with the making of such overadvance, an amount equal
          to one percent (1%) of the Overadvance, provided that the payment of
          such amount does not cause the interest ON the obligations to exceed
          the Maximum Legal Rate. The Revolving Credit Loans shall be used
          solely (i) for the satisfaction of existing Indebtedness of Borrower
          to F&M Bank and Trust Company of Tulsa, oklahoma, (ii) for the
          satisfaction of certain trade payables and other unsecured
          indebtedness owed to trade creditors of Borrower, (iii) for Borrower's
          general operating capital needs to the extent not inconsistent with
          the provisions of this Agreement, and (iv) for the payment of any of
          the fees specified in Section 3.2 of this Agreement and, to the extent
          approved by Lender, to the payment of any costs associated with the
          closing of the transactions contemplated by this Agreement.

                 (B) Subject to the terms and conditions of this Agreement,
          Lender agrees to make a term loan to Borrower in the aggregate
          principal amount of up to $500,000, which shall bear interest and be
          repayable in accordance with the terms of the Term Note and shall be
          secured by the Collateral. The Term Loan may be advanced in two
          advances in the amounts of up to $385,000 and $115,000, respectively.
          The proceeds of the first advance shall be used by Borrower solely for
          the purpose of


                                      -5-
<PAGE>
 
          purchasing the Real Property other than the Real Property located in
          Conroe, Texas, and the proceeds of the second advance shall be used
          solely for the purpose of purchasing real Property.

                 (C) Provided that no Default or Event of Default has
          occurred, Borrower may request from time to time that Lender provide
          LC Guaranties to support Letters of Credit to be issued for the
          account of Borrower, not to exceed the face amount of $500,000
          outstanding at any time. Borrower acknowledges that execution of any
          LC Guaranty requested by Borrower shall be in the sole discretion of
          Lender, and that any Letter of Credit will be subject to the terms,
          conditions and requirements of the Person issuing such Letter of
          Credit. If at any time Lender is called upon under an LC Guaranty to
          reimburse to the issuer of any Letter of Credit any draft drawn upon
          such Letter of Credit, Borrower shall be deemed to have borrowed, as
          of the date of such reimbursement, a Revolving Credit Loan in the
          amount of such reimbursement."

     3.   INTEREST AND CHARGES.

          (a) Section 3.1(A) of the Agreement is hereby deleted, and in place
     thereof shall be the following:

                    "(A) The principal amount of the Term Loan outstanding from
          day-to-day shall bear interest, calculated daily at a fluctuating rate
          per annum equal to the lesser of (i) 2.5% above the Base Rate (the
          "Annual Term Rate"), or (ii) the Maximum Legal Rate. The principal
          amount of the Revolving Credit Loans outstanding from day-to-day shall
          bear interest, calculated daily at a fluctuating rate per annum equal
          to the lesser of (i) 2.0% (or such lesser percentage as may be
          provided by subsection (H) hereof) above the Base Rate (the "Annual
          Revolving Rate"), or (ii) the Maximum Legal Rate."

          (b) All references in Section 3.1(H) of the Agreement to the
     "Applicable Rate" are hereby amended to be references to the "Annual
     Revolving Rate."

     4.   FEES. The following Sections 3.2(D) and 3.2(E) are hereby added to the
Agreement:

                    "(D)  Term Loan Closing Fee.  On or before the first Term
          Loan Closing Date, Borrower shall pay to Lender a Term Loan closing
          fee of $5,000, which shall be


                                      -6-
<PAGE>
 
     deemed fully earned and nonrefundable at the first Term Loan Closing Date
     and shall be paid concurrently with the first advance under the Term Loan.
     Such fee shall compensate Lender for the costs associated with the
     origination, structuring, processing, approving and closing of the Term
     Loan, including, but not limited to, administrative, out-of-pocket, general
     overhead and lost opportunity costs, but not including any expenses for
     which Borrower has agreed to reimburse Lender pursuant to any other
     provision of this Agreement (for example, reasonable attorney's fees
     incurred by Lender) or any other Agreement."

               "(E)  LC Guaranty Fee. Borrower agrees to pay to Lender a monthly
     LC Guaranty Fee, equal to 2.5% per annum of the face amount of the Letters
     of Credit (if any) outstanding during such month for which Lender has
     issued LC Guaranties. The LC Guaranty Fee shall be payable monthly in
     arrears, beginning July 1, 1992 and continuing regularly thereafter during
     the term of this Agreement and upon the termination hereof. Such LC
     Guaranty Fee shall be in addition to any fee charged by the issuer of any
     Letter of Credit."

     5.   PAYMENTS.  All references in Section 3.4 of the Agreement to "Loan" or
"Loans" are hereby amended to be references to "Revolving Credit Loan" or
"Revolving Credit Loans" and Section 3.4 is further amended by adding thereto
the following subsection (D):

               "(D) Notwithstanding Section 3.5, any payment received on the
     Loans by Lender from or on behalf of Borrower shall first be applied to the
     payment of any principal and interest then due and payable under either
     Loan in such manner as Lender shall determine in its sole discretion, with
     the balance of any such payment being applied by Lender pursuant to the
     provisions of Section 3.5. Borrower hereby irrevocably authorizes Lender,
     in Lender's sole discretion and without any obligation, to advance to
     Borrower, and to charge to the Loan Account hereunder as a Revolving Credit
     Loan, a sum sufficient on any date to pay all principal and interest then
     due and owing on any Loan.

     6.   APPLICATION OF PAYMENTS AND COLLECTIONS. A new sentence is hereby
added to the end of Section 3.5 of the Agreement, which sentence shall read as
follows:

     "In no event shall such credit balance be applied or be deemed to have been
     applied as a prepayment of the Term Loan unless as requested by Borrower,
     but Lender may offset such credit balance against the obligations upon or
     after the occurrence of an Event of Default."


                                      -7-
<PAGE>
 
     7.   CONDITIONS PRECEDENT. The following Section 10.3 is hereby added to
the Agreement:

          "10.3 CONDITIONS TO ADVANCES UNDER TERM LOAN. Notwithstanding any
     other provision of this Agreement or any of the other Agreements, and
     without affecting in any manner the rights of Lender under the other
     Sections of this Agreement (including, without limitation, Sections 10.1
     and 10.2), it is understood and agreed that Lender will not make any
     advance under the Term Loan unless and until each of the following
     additional conditions has been and continues to be satisfied, all in form
     and substance satisfactory to Lender and its counsel:

               (A) Borrower shall have executed and delivered to Lender the Term
     Note;

               (B) Borrower shall have provided evidence that Borrower has
     purchased, or will purchase with the proceeds of such advance, the Real
     Property to be purchased as described in Section 2.1(B) hereof, free and
     clear of any and all Liens, other than the Lien created by the Mortgages;

               (C) Borrower shall have executed and delivered to Lender the
     Mortgages covering the Real Property to be purchased, which Mortgages shall
     have been recorded with the appropriate filing officers or shall be duly
     recorded immediately after acquisition of the Real Property by Borrower;

               (D) Borrower shall have delivered to Lender, at Borrower's
     expense, mortgagee title insurance policies (or commitments to issue
     mortgagee title insurance policies, provided Borrower simultaneously pays
     all premiums and satisfies all conditions necessary for issuance of such
     policies) issued by a title insurance company satisfactory to Lender
     insuring Lender as mortgagee; such policies shall be in form and substance
     satisfactory to Lender and shall insure a valid first Lien in favor of
     Lender on the Real Property to be purchased, subject only to those
     exceptions acceptable to Lender and its counsel;

               (E) Borrower shall have delivered to Lender such other documents,
     including, without limitation, surveys of the Real Property to be
     purchased, certificates of corporate resolutions and incumbency of
     officers, opinions of counsel, and other documents and instruments as
     Lender and its counsel may reasonably request relating to the Real
     Property, the Term Note and the Mortgages;


                                      -8-
<PAGE>
 
               (F) The first Term Loan Closing Date must occur on or before June
     15, 1992 and the second Term Loan Closing Date must occur on or before
     September 30, 1992."

     8.   EXHIBITS. All references in the Agreement (as amended hereby) to
Exhibits "J", "K" and "L" shall hereafter be deemed to be references to Exhibits
"J", "K" and "L", respectively, attached hereto.

     9.   CONDITIONS. The obligation of Lender to be bound by the provisions of
this Amendment shall be subject to the fulfillment of the following conditions
precedent on or before the date hereof:

          (a) Lender shall have received the following, duly executed by each
     party thereto, other than Lender:

              (i)   this Amendment; and

              (ii)  all other documents Lender may reasonably request with
          respect to any matter relevant to this Amendment or the transactions
          contemplated hereby.

          (b) Borrower and Guarantor shall have performed and complied with all
     agreements and conditions contained in the Agreement and the other
     Agreements which are required to be performed or complied with by Borrower
     or Guarantor before or on the date hereof.

          (c) The representations and warranties contained in the Agreement, as
     amended hereby, and the other Agreements shall be true and correct in all
     material respects as of the date hereof, with the same force and effect as
     though made on and as of this date.

          (d) No material adverse change shall have occurred in the business
     operations, financial condition or prospects of Borrower or Guarantor, and
     no material adverse litigation shall be pending or, to the knowledge of
     Borrower or Guarantor, threatened, against Borrower or Guarantor.

          (e) All corporate and legal proceedings and all documents required to
     be completed and executed by the provisions of, and all instruments to be
     executed in connection with the transactions contemplated by, this
     Amendment and any related agreements shall be satisfactory in form and
     substance to Lender.

     10.  EXISTING DEFAULTS. As of the date hereof, there exist Events of
Default under the Agreement. The execution of this Amendment is not intended to,
and shall not be deemed, a waiver of any such existing Events of Default.

                                      -9-
<PAGE>
 
     11.  EXPENSES. Borrower shall pay all out-of-pocket expenses arising in
connection with the preparation, execution, delivery and administration of this
Amendment, including, but not limited to, all reasonable legal fees and expenses
incurred by Lender.

     12.  CONTINUED EFFECT. Except to the extent amended hereby, all terms,
provisions and conditions of the Agreement and all of the other Agreements shall
continue in full force and effect and shall remain enforceable and binding in
accordance with their respective terms.

     13.  COUNTERPARTS. This Amendment may be executed in any number of
counterparts, each of which shall for all purposes be deemed an original and all
of which are identical. All parties need not execute the same counterpart.

     14.  FINAL AGREEMENT.  THIS WRITTEN AMENDMENT AND THE OTHER LOAN DOCUMENTS
REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY
EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE
PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

     EXECUTED as of the date first above written.

                              RED MAN PIPE & SUPPLY CO.

                              By: /s/ DEE PAIGE
                              Name: DEE PAIGE
                              Title: VICE PRESIDENT OF FINANCE


                              BARCLAYS BUSINESS CREDIT, INC.

                              By: /s/ JOY L.  BARTHOLOMEW
                              Name: JOY L.  BARTHOLOMEW
                              Title: Regional Vice President



                                      -10-
<PAGE>
 
The undersigned Guarantor, having guaranteed to Lender the payment of the
obligations, as such term is defined in the Unconditional Limited Guaranty (the
"Guaranty") executed by Guarantor on May 3, 1991, hereby acknowledges, confirms,
and agrees that (i) the execution and delivery of this Amendment does not alter,
affect, diminish, release or reduce his liability under the Guaranty, (ii) the
Guaranty is in full force and effect to secure the Obligations described
therein, and (iii) the obligations secured by the Guaranty include, without
limitation, any Term Loan advanced pursuant to the terms of this Amendment.



                              /s/ LEWIS B.  KETCHUM
                              LEWIS B. KETCHUM


                                     -11-