Exhibit
4.6


Exhibit
A




SUPPLEMENTAL
INDENTURE (this “Supplemental Indenture”), dated as of December 14, 2005, among
Targa Gas Marketing LLC (the “Guaranteeing Subsidiary”), a subsidiary of Targa
Resources, Inc. (or its permitted successor), a Delaware corporation (the
“Company”), Targa Resources Finance Corporation, a Delaware corporation (the
“Co-Issuer”), the other Subsidiary Guarantors (as defined in the Indenture
referred to herein) and Wells Fargo Bank, National Association, as trustee under
the Indenture referred to below (the “Trustee”).




W
I T N E S S E T H




WHEREAS,
the Company and the Co-Issuer have heretofore executed and delivered to the
Trustee a senior unsecured indenture (the “Indenture”), dated as of October 31,
2005 providing for the issuance of 81⁄2% Senior Notes Due 2013 (the
“Notes”);




WHEREAS,
the Indenture provides that under certain circumstances the Guaranteeing
Subsidiary shall execute and deliver to the Trustee a supplemental indenture
pursuant to which the Guaranteeing Subsidiary shall unconditionally guarantee
all of the Company’s and the Co-Issuer’s Obligations under the Notes and the
Indenture on the terms and conditions set forth herein (the “Subsidiary
Guarantee”); and




WHEREAS,
pursuant to Section 901 of the Indenture, the Trustee is authorized to execute
and deliver this Supplemental Indenture.




NOW,
THEREFORE, in consideration of the foregoing and for other good and valuable
consideration, the receipt of which is hereby acknowledged, the Guaranteeing
Subsidiary and the Trustee mutually covenant and agree for the equal and ratable
benefit of the Holders of the Notes as follows:




1.           CAPITALIZED
TERMS.  Capitalized terms used herein without definition shall have
the meanings assigned to them in the Indenture.




2.           AGREEMENT
TO SUBSIDIARY GUARANTEE.  The Guaranteeing Subsidiary hereby agrees to
provide an unconditional Subsidiary Guarantee on the terms and subject to the
conditions set forth in the Note Subsidiary Guarantee and in the Indenture
including but not limited to Article 12 thereof.




3.           NO
RECOURSE AGAINST OTHERS.  No past, present or future director,
officer, employee, incorporator, stockholder or agent of the Guaranteeing
Subsidiary, as such, shall have any liability for any obligations of the
Company, the Co-Issuer or any Guaranteeing Subsidiary under the Notes, any Note
Guarantees, the Indenture or this Supplemental Indenture or for any claim based
on, in respect of, or by reason of, such obligations or their creation; provided
that the foregoing shall not limit any of the Company’s or the Co-Issuer’s
obligations under the Notes.  Each Holder of the Notes by accepting a
Note waives and releases all such liability.  The waiver and release
are part of the consideration for issuance of the Notes.  Such waiver
may not be effective to waive liabilities under the federal securities laws and
it is the view of the SEC that such a waiver is against public
policy.




4.           GOVERNING
LAW.  THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.




5.           COUNTERPARTS.  The
parties may sign any number of copies of this Supplemental
Indenture.  Each signed copy shall be an original, but all of them
together represent the same agreement.




6.           EFFECT
OF HEADINGS.  The Section headings herein are for convenience only and
shall not affect the construction hereof.







7.           THE
TRUSTEE.  The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture or for or in respect of the recitals contained herein, all of which
recitals are made solely by the Guaranteeing Subsidiary, the Co-Issuer and the
Company. IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed and attested, all as of the date first above
written.




Dated:
December 14, 2005









TARGA GAS MARKETING LLC





By: __/s/ Jeffrey J.
McParland______


Name:               Jeffrey
J. McParland


Title:
            Executive
      Vice President and


Chief
      Financial Officer












TARGA RESOURCES, INC.





By: __/s/ Jeffrey J.
McParland______


Name:               Jeffrey
J. McParland


Title:
            Executive
      Vice President and


Chief
      Financial Officer








TARGA
RESOURCES FINANCE CORPORATION





By: __/s/ Jeffrey J.
McParland______


Name:               Jeffrey
J. McParland


Title:
            Executive
      Vice President and


Chief
      Financial Officer








TARGA
TEXAS FIELD SERVICES LP


TARGA
LOUISIANA FIELD SERVICES LLC


TARGA
LOUISIANA INTRASTATE LLC


TARGA
RESOURCES LLC


TARGA
RESOURCES II LLC


TARGA
RESOURCES HOLDINGS GP LLC


TARGA
RESOURCES HOLDINGS LP


TARGA
RESOURCES TEXAS GP LLC


TARGA
TEXAS FIELD SERVICES LP


TARGA
MIDSTREAM GP LLC


TARGA
MIDSTREAM SERVICES LIMITED PARTNERSHIP (formerly known as Dynegy Midstream
Services, Limited Partnership)


TARGA
ENERGY PIPELINE LLC (formerly known as Dynegy Energy Pipeline,
L.L.C.)


TARGA
INTRASTATE PIPELINE LLC .


(formerly
known as Dynegy Intrastate Pipeline, L.L.C.)


TARGA
LIQUIDS GP LLC (formerly known as Dynegy Liquids G.P., L.L.C.)


TARGA
LIQUIDS MARKETING AND TRADE


(formerly
known as Dynegy Liquids Marketing and Trade)


TARGA NGL
PIPELINE COMPANY LLC


(formerly
known as Dynegy NGL Pipeline


Company,
LLC)


TARGA OPI
LLC (formerly known as Dynegy OPI, LLC)


TARGA
REGULATED HOLDINGS LLC


(formerly
known as Dynegy Regulated Holdings LLC)


MIDSTREAM
BARGE COMPANY LLC (formerly known as Midstream Barge Company
L.L.C.)










By: __/s/ Jeffrey J.
McParland______


Name:               Jeffrey
J. McParland


Title:
            Executive
      Vice President and


Chief
      Financial Officer







WELLS
FARGO BANK, NATIONAL




ASSOCIATION,
as Trustee




By:           __/s/ Joseph
O’Donnell_______




Authorized Signatory